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Posted to commits@htrace.apache.org by st...@apache.org on 2015/06/18 00:23:08 UTC

[5/5] incubator-htrace git commit: HTRACE-183 Have go build into the target dir rather than under src

HTRACE-183 Have go build into the target dir rather than under src

Move go from src/go to go.

Change where htraced looks for the web dir from ../../web to ../web.

Have gobuild.py create a symlink to the web dir at src/web beside
the go dir so can do in-situ development.


Project: http://git-wip-us.apache.org/repos/asf/incubator-htrace/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-htrace/commit/42b2f6a2
Tree: http://git-wip-us.apache.org/repos/asf/incubator-htrace/tree/42b2f6a2
Diff: http://git-wip-us.apache.org/repos/asf/incubator-htrace/diff/42b2f6a2

Branch: refs/heads/master
Commit: 42b2f6a2c22046fe5da348c301d49521f1501bf9
Parents: a560a55
Author: stack <st...@duboce.net>
Authored: Wed Jun 17 14:51:42 2015 -0700
Committer: stack <st...@duboce.net>
Committed: Wed Jun 17 15:22:43 2015 -0700

----------------------------------------------------------------------
 htrace-htraced/go/Godeps/Godeps.json            |  30 +
 htrace-htraced/go/format.sh                     |  40 +
 htrace-htraced/go/gobuild.sh                    | 119 +++
 .../go/src/org/apache/htrace/client/client.go   | 245 +++++
 .../go/src/org/apache/htrace/client/hclient.go  | 157 +++
 .../go/src/org/apache/htrace/common/log.go      | 296 ++++++
 .../go/src/org/apache/htrace/common/log_test.go | 122 +++
 .../go/src/org/apache/htrace/common/process.go  |  67 ++
 .../go/src/org/apache/htrace/common/query.go    | 126 +++
 .../src/org/apache/htrace/common/query_test.go  |  50 +
 .../go/src/org/apache/htrace/common/rest.go     |  29 +
 .../go/src/org/apache/htrace/common/rpc.go      |  81 ++
 .../go/src/org/apache/htrace/common/span.go     | 140 +++
 .../src/org/apache/htrace/common/span_test.go   |  66 ++
 .../src/org/apache/htrace/common/test_util.go   |  74 ++
 .../go/src/org/apache/htrace/conf/config.go     | 266 +++++
 .../src/org/apache/htrace/conf/config_keys.go   |  86 ++
 .../src/org/apache/htrace/conf/config_test.go   | 138 +++
 .../go/src/org/apache/htrace/conf/xml.go        |  61 ++
 .../go/src/org/apache/htrace/htrace/cmd.go      | 317 ++++++
 .../go/src/org/apache/htrace/htrace/file.go     | 138 +++
 .../src/org/apache/htrace/htrace/file_test.go   | 164 +++
 .../go/src/org/apache/htrace/htrace/graph.go    | 116 +++
 .../src/org/apache/htrace/htrace/graph_test.go  |  84 ++
 .../go/src/org/apache/htrace/htrace/queries.go  | 161 +++
 .../org/apache/htrace/htraced/client_test.go    | 206 ++++
 .../src/org/apache/htrace/htraced/datastore.go  | 999 +++++++++++++++++++
 .../org/apache/htrace/htraced/datastore_test.go | 514 ++++++++++
 .../go/src/org/apache/htrace/htraced/hrpc.go    | 251 +++++
 .../go/src/org/apache/htrace/htraced/htraced.go | 140 +++
 .../org/apache/htrace/htraced/mini_htraced.go   | 165 +++
 .../go/src/org/apache/htrace/htraced/rest.go    | 308 ++++++
 .../go/src/org/apache/htrace/test/random.go     |  72 ++
 .../go/src/org/apache/htrace/test/util.go       |  33 +
 htrace-htraced/pom.xml                          |  16 +-
 htrace-htraced/src/go/Godeps/Godeps.json        |  30 -
 htrace-htraced/src/go/format.sh                 |  40 -
 htrace-htraced/src/go/gobuild.sh                | 116 ---
 .../go/src/org/apache/htrace/client/client.go   | 245 -----
 .../go/src/org/apache/htrace/client/hclient.go  | 157 ---
 .../src/go/src/org/apache/htrace/common/log.go  | 296 ------
 .../go/src/org/apache/htrace/common/log_test.go | 122 ---
 .../go/src/org/apache/htrace/common/process.go  |  67 --
 .../go/src/org/apache/htrace/common/query.go    | 126 ---
 .../src/org/apache/htrace/common/query_test.go  |  50 -
 .../src/go/src/org/apache/htrace/common/rest.go |  29 -
 .../src/go/src/org/apache/htrace/common/rpc.go  |  81 --
 .../src/go/src/org/apache/htrace/common/span.go | 140 ---
 .../src/org/apache/htrace/common/span_test.go   |  66 --
 .../src/org/apache/htrace/common/test_util.go   |  74 --
 .../src/go/src/org/apache/htrace/conf/config.go | 266 -----
 .../src/org/apache/htrace/conf/config_keys.go   |  86 --
 .../src/org/apache/htrace/conf/config_test.go   | 138 ---
 .../src/go/src/org/apache/htrace/conf/xml.go    |  61 --
 .../src/go/src/org/apache/htrace/htrace/cmd.go  | 317 ------
 .../src/go/src/org/apache/htrace/htrace/file.go | 138 ---
 .../src/org/apache/htrace/htrace/file_test.go   | 164 ---
 .../go/src/org/apache/htrace/htrace/graph.go    | 116 ---
 .../src/org/apache/htrace/htrace/graph_test.go  |  84 --
 .../go/src/org/apache/htrace/htrace/queries.go  | 161 ---
 .../org/apache/htrace/htraced/client_test.go    | 206 ----
 .../src/org/apache/htrace/htraced/datastore.go  | 999 -------------------
 .../org/apache/htrace/htraced/datastore_test.go | 514 ----------
 .../go/src/org/apache/htrace/htraced/hrpc.go    | 251 -----
 .../go/src/org/apache/htrace/htraced/htraced.go | 140 ---
 .../org/apache/htrace/htraced/mini_htraced.go   | 165 ---
 .../go/src/org/apache/htrace/htraced/rest.go    | 308 ------
 .../src/go/src/org/apache/htrace/test/random.go |  72 --
 .../src/go/src/org/apache/htrace/test/util.go   |  33 -
 pom.xml                                         |   4 +-
 70 files changed, 5871 insertions(+), 5868 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/Godeps/Godeps.json
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/Godeps/Godeps.json b/htrace-htraced/go/Godeps/Godeps.json
new file mode 100644
index 0000000..47aa90e
--- /dev/null
+++ b/htrace-htraced/go/Godeps/Godeps.json
@@ -0,0 +1,30 @@
+{
+    "ImportPath": "git-wip-us.apache.org/repos/asf/incubator-htrace.git",
+    "GoVersion": "go1.3.1",
+    "Deps": [
+        {
+            "ImportPath": "github.com/alecthomas/kingpin",
+            "Rev": "afafa8aab106d31c9dc8f5e562b3f30f6246c3d4"
+        },
+        {
+            "ImportPath": "github.com/alecthomas/units",
+            "Rev": "6b4e7dc5e3143b85ea77909c72caf89416fc2915"
+        },
+        {
+            "ImportPath": "github.com/gorilla/context",
+            "Rev": "215affda49addc4c8ef7e2534915df2c8c35c6cd"
+        },
+        {
+            "ImportPath": "github.com/gorilla/mux",
+            "Rev": "e444e69cbd2e2e3e0749a2f3c717cec491552bbf"
+        },
+        {
+            "ImportPath": "github.com/jmhodges/levigo",
+            "Rev": "2c43dde93d0e056173706534afd514fcbc1dd578"
+        },
+        {
+            "ImportPath": "github.com/ugorji/go/codec",
+            "Rev": "08bbe4aa39b9f189f4e294b5c8408b5fa5787bb2"
+        }
+    ]
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/format.sh
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/format.sh b/htrace-htraced/go/format.sh
new file mode 100755
index 0000000..46aa5b1
--- /dev/null
+++ b/htrace-htraced/go/format.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+#
+# Reformats the HTrace code.
+#
+# ./format.sh               Reformats all code.
+#
+
+die() {
+    echo $@
+    exit 1
+}
+
+# Check for gofmt.  It should be installed whenever the go developement tools
+# are installed.
+which gofmt &> /dev/null
+[ $? -ne 0 ] && die "You must install the gofmt code reformatting formatting tool."
+
+# Find go sources.  We assume no newlines or whitespace in file names.
+SCRIPT_DIR="$(cd "$( dirname $0 )" && pwd)"
+find "${SCRIPT_DIR}/src" -noleaf -xdev -name '*.go' | xargs -L 1 gofmt -w

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/gobuild.sh
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/gobuild.sh b/htrace-htraced/go/gobuild.sh
new file mode 100755
index 0000000..259e6a7
--- /dev/null
+++ b/htrace-htraced/go/gobuild.sh
@@ -0,0 +1,119 @@
+#!/usr/bin/env bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+#
+# Builds the HTrace server code.
+#
+# ./gobuild.sh                Builds the code.
+# ./gobuild.sh test           Builds and runs all unit tests.
+# ./gobuild.sh bench          Builds and runs all benchmarks
+#
+
+die() {
+    echo $@
+    exit 1
+}
+
+ACTION=install
+if [ $# -gt 0 ]; then
+    ACTION="${1}"
+    shift
+fi
+RELEASE_VERSION=${RELEASE_VERSION:-unknown}
+
+# Set up directories.  The build/ directory is where build dependencies and
+# build binaries should go.
+SCRIPT_DIR="$(cd "$( dirname $0 )" && pwd)"
+export GOBIN="${SCRIPT_DIR}/build"
+mkdir -p "${GOBIN}" || die "failed to mkdir -p ${GOBIN}"
+cd "${GOBIN}" || die "failed to cd to ${SCRIPT_DIR}"
+export GOPATH="${GOBIN}:${SCRIPT_DIR}"
+
+# Use the unsafe package when possible to get greater speed.  For example,
+# go-codec can bypass the overhead of converting between []byte and string in
+# some cases when using unsafe.
+TAGS="-tags unsafe"
+
+# Check for go
+which go &> /dev/null
+if [ $? -ne 0 ]; then
+    cat <<EOF
+You must install the Golang programming language.
+
+If you are using Debian, try "apt-get install golang".
+For Red Hat, try "yum install go".
+For other distributions and operating systems use your packaging tool.
+EOF
+exit 1
+fi
+
+# Check for libleveldb.so
+if [ -x "/sbin/ldconfig" ]; then
+    # Suse requires ldconfig to be run via the absolute path
+    ldconfig=/sbin/ldconfig
+else
+    which ldconfig &> /dev/null
+    [ $? -eq 0 ] && ldconfig=ldconfig
+fi
+if [ -n "${ldconfig}" ]; then
+    if "${ldconfig}" -p | grep -q libleveldb; then
+        :
+    else
+        echo "You must install the leveldb-devel package (or distro-specific equivalent.)"
+        exit 1
+    fi
+fi
+
+case $ACTION in
+clean)
+    rm -rf -- "${GOBIN}" ${SCRIPT_DIR}/pkg
+    ;;
+install)
+    # Ensure that we have the godep program.
+    PATH="${PATH}:${GOBIN}"
+    which godep &> /dev/null
+    if [ $? -ne 0 ]; then
+        echo "Installing godep..."
+        go get github.com/tools/godep || die "failed to get godep"
+    fi
+
+    # Download dependencies into the build directory.
+    echo "godep restore..."
+    godep restore || die "failed to set up dependencies"
+
+    # Discover the git version
+    GIT_VERSION=$(git rev-parse HEAD)
+    [ $? -eq 0 ] || GIT_VERSION="unknown"
+
+    # Inject the release and git version into the htraced ldflags.
+    FLAGS="-X main.RELEASE_VERSION ${RELEASE_VERSION} -X main.GIT_VERSION ${GIT_VERSION}"
+    go install ${TAGS} -ldflags "${FLAGS}" -v org/apache/htrace/... "$@"
+    # Make a symlink to web src dir so can do development in-situ out
+    # of build dir. This is ugly but blame go build.
+    ln -fs "../src/web" "${GOBIN}/../"
+    ;;
+bench)
+    go test org/apache/htrace/... ${TAGS} -test.bench=. "$@"
+    ;;
+*)
+    go ${ACTION} org/apache/htrace/... ${TAGS} "$@"
+    ;;
+esac

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/client/client.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/client/client.go b/htrace-htraced/go/src/org/apache/htrace/client/client.go
new file mode 100644
index 0000000..6a62e81
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/client/client.go
@@ -0,0 +1,245 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package client
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"org/apache/htrace/common"
+	"org/apache/htrace/conf"
+)
+
+// A golang client for htraced.
+// TODO: fancier APIs for streaming spans in the background, optimize TCP stuff
+
+func NewClient(cnf *conf.Config) (*Client, error) {
+	hcl := Client{}
+	hcl.restAddr = cnf.Get(conf.HTRACE_WEB_ADDRESS)
+	hcl.hrpcAddr = cnf.Get(conf.HTRACE_HRPC_ADDRESS)
+	return &hcl, nil
+}
+
+type Client struct {
+	// REST address of the htraced server.
+	restAddr string
+
+	// HRPC address of the htraced server.
+	hrpcAddr string
+
+	// The HRPC client, or null if it is not enabled.
+	hcr *hClient
+}
+
+// Get the htraced server information.
+func (hcl *Client) GetServerInfo() (*common.ServerInfo, error) {
+	buf, _, err := hcl.makeGetRequest("server/info")
+	if err != nil {
+		return nil, err
+	}
+	var info common.ServerInfo
+	err = json.Unmarshal(buf, &info)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error: error unmarshalling response "+
+			"body %s: %s", string(buf), err.Error()))
+	}
+	return &info, nil
+}
+
+// Get information about a trace span.  Returns nil, nil if the span was not found.
+func (hcl *Client) FindSpan(sid common.SpanId) (*common.Span, error) {
+	buf, rc, err := hcl.makeGetRequest(fmt.Sprintf("span/%016x", uint64(sid)))
+	if err != nil {
+		if rc == http.StatusNoContent {
+			return nil, nil
+		}
+		return nil, err
+	}
+	var span common.Span
+	err = json.Unmarshal(buf, &span)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error unmarshalling response "+
+			"body %s: %s", string(buf), err.Error()))
+	}
+	return &span, nil
+}
+
+func (hcl *Client) WriteSpans(req *common.WriteSpansReq) error {
+	if hcl.hrpcAddr == "" {
+		return hcl.writeSpansHttp(req)
+	}
+	hcr, err := newHClient(hcl.hrpcAddr)
+	if err != nil {
+		return err
+	}
+	defer hcr.Close()
+	return hcr.writeSpans(req)
+}
+
+func (hcl *Client) writeSpansHttp(req *common.WriteSpansReq) error {
+	var w bytes.Buffer
+	var err error
+	for i := range req.Spans {
+		var buf []byte
+		buf, err = json.Marshal(req.Spans[i])
+		if err != nil {
+			return errors.New(fmt.Sprintf("Error serializing span: %s",
+				err.Error()))
+		}
+		_, err = w.Write(buf)
+		if err != nil {
+			return errors.New(fmt.Sprintf("Error writing span: %s",
+				err.Error()))
+		}
+		_, err = w.Write([]byte{'\n'})
+		//err = io.WriteString(&w, "\n")
+		if err != nil {
+			return errors.New(fmt.Sprintf("Error writing: %s",
+				err.Error()))
+		}
+	}
+	customHeaders := make(map[string]string)
+	if req.DefaultPid != "" {
+		customHeaders["htrace-pid"] = req.DefaultPid
+	}
+	_, _, err = hcl.makeRestRequest("POST", "writeSpans",
+		&w, customHeaders)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Find the child IDs of a given span ID.
+func (hcl *Client) FindChildren(sid common.SpanId, lim int) ([]common.SpanId, error) {
+	buf, _, err := hcl.makeGetRequest(fmt.Sprintf("span/%016x/children?lim=%d",
+		uint64(sid), lim))
+	if err != nil {
+		return nil, err
+	}
+	var spanIds []common.SpanId
+	err = json.Unmarshal(buf, &spanIds)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error: error unmarshalling response "+
+			"body %s: %s", string(buf), err.Error()))
+	}
+	return spanIds, nil
+}
+
+// Make a query
+func (hcl *Client) Query(query *common.Query) ([]common.Span, error) {
+	in, err := json.Marshal(query)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error marshalling query: %s", err.Error()))
+	}
+	var out []byte
+	var url = fmt.Sprintf("query?query=%s", in)
+	out, _, err = hcl.makeGetRequest(url)
+	if err != nil {
+		return nil, err
+	}
+	var spans []common.Span
+	err = json.Unmarshal(out, &spans)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error unmarshalling results: %s", err.Error()))
+	}
+	return spans, nil
+}
+
+var EMPTY = make(map[string]string)
+
+func (hcl *Client) makeGetRequest(reqName string) ([]byte, int, error) {
+	return hcl.makeRestRequest("GET", reqName, nil, EMPTY)
+}
+
+// Make a general JSON REST request.
+// Returns the request body, the response code, and the error.
+// Note: if the response code is non-zero, the error will also be non-zero.
+func (hcl *Client) makeRestRequest(reqType string, reqName string, reqBody io.Reader,
+	customHeaders map[string]string) ([]byte, int, error) {
+	url := fmt.Sprintf("http://%s/%s",
+		hcl.restAddr, reqName)
+	req, err := http.NewRequest(reqType, url, reqBody)
+	req.Header.Set("Content-Type", "application/json")
+	for k, v := range customHeaders {
+		req.Header.Set(k, v)
+	}
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, -1, errors.New(fmt.Sprintf("Error: error making http request to %s: %s\n", url,
+			err.Error()))
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, resp.StatusCode,
+			errors.New(fmt.Sprintf("Error: got bad response status from %s: %s\n", url, resp.Status))
+	}
+	var body []byte
+	body, err = ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, -1, errors.New(fmt.Sprintf("Error: error reading response body: %s\n", err.Error()))
+	}
+	return body, 0, nil
+}
+
+// Dump all spans from the htraced daemon.
+func (hcl *Client) DumpAll(lim int, out chan *common.Span) error {
+	defer func() {
+		close(out)
+	}()
+	searchId := common.SpanId(0)
+	for {
+		q := common.Query{
+			Lim: lim,
+			Predicates: []common.Predicate{
+				common.Predicate{
+					Op:    "ge",
+					Field: "spanid",
+					Val:   searchId.String(),
+				},
+			},
+		}
+		spans, err := hcl.Query(&q)
+		if err != nil {
+			return errors.New(fmt.Sprintf("Error querying spans with IDs at or after "+
+				"%s: %s", searchId.String(), err.Error()))
+		}
+		if len(spans) == 0 {
+			return nil
+		}
+		for i := range spans {
+			out <- &spans[i]
+		}
+		searchId = spans[len(spans)-1].Id + 1
+	}
+}
+
+func (hcl *Client) Close() {
+	if hcl.hcr != nil {
+		hcl.hcr.Close()
+	}
+	hcl.restAddr = ""
+	hcl.hcr = nil
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/client/hclient.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/client/hclient.go b/htrace-htraced/go/src/org/apache/htrace/client/hclient.go
new file mode 100644
index 0000000..608dd59
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/client/hclient.go
@@ -0,0 +1,157 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package client
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"github.com/ugorji/go/codec"
+	"io"
+	"net"
+	"net/rpc"
+	"org/apache/htrace/common"
+)
+
+type hClient struct {
+	rpcClient *rpc.Client
+}
+
+type HrpcClientCodec struct {
+	rwc    io.ReadWriteCloser
+	length uint32
+}
+
+func (cdc *HrpcClientCodec) WriteRequest(req *rpc.Request, msg interface{}) error {
+	methodId := common.HrpcMethodNameToId(req.ServiceMethod)
+	if methodId == common.METHOD_ID_NONE {
+		return errors.New(fmt.Sprintf("HrpcClientCodec: Unknown method name %s",
+			req.ServiceMethod))
+	}
+	mh := new(codec.MsgpackHandle)
+	mh.WriteExt = true
+	w := bytes.NewBuffer(make([]byte, 0, 2048))
+	enc := codec.NewEncoder(w, mh)
+	err := enc.Encode(msg)
+	if err != nil {
+		return errors.New(fmt.Sprintf("HrpcClientCodec: Unable to marshal "+
+			"message as msgpack: %s", err.Error()))
+	}
+	buf := w.Bytes()
+	if len(buf) > common.MAX_HRPC_BODY_LENGTH {
+		return errors.New(fmt.Sprintf("HrpcClientCodec: message body is %d "+
+			"bytes, but the maximum message size is %d bytes.",
+			len(buf), common.MAX_HRPC_BODY_LENGTH))
+	}
+	hdr := common.HrpcRequestHeader{
+		Magic:    common.HRPC_MAGIC,
+		MethodId: methodId,
+		Seq:      req.Seq,
+		Length:   uint32(len(buf)),
+	}
+	err = binary.Write(cdc.rwc, binary.LittleEndian, &hdr)
+	if err != nil {
+		return errors.New(fmt.Sprintf("Error writing header bytes: %s",
+			err.Error()))
+	}
+	_, err = cdc.rwc.Write(buf)
+	if err != nil {
+		return errors.New(fmt.Sprintf("Error writing body bytes: %s",
+			err.Error()))
+	}
+	return nil
+}
+
+func (cdc *HrpcClientCodec) ReadResponseHeader(resp *rpc.Response) error {
+	hdr := common.HrpcResponseHeader{}
+	err := binary.Read(cdc.rwc, binary.LittleEndian, &hdr)
+	if err != nil {
+		return errors.New(fmt.Sprintf("Error reading response header "+
+			"bytes: %s", err.Error()))
+	}
+	resp.ServiceMethod = common.HrpcMethodIdToMethodName(hdr.MethodId)
+	if resp.ServiceMethod == "" {
+		return errors.New(fmt.Sprintf("Error reading response header: "+
+			"invalid method ID %d.", hdr.MethodId))
+	}
+	resp.Seq = hdr.Seq
+	if hdr.ErrLength > 0 {
+		if hdr.ErrLength > common.MAX_HRPC_ERROR_LENGTH {
+			return errors.New(fmt.Sprintf("Error reading response header: "+
+				"error message was %d bytes long, but "+
+				"MAX_HRPC_ERROR_LENGTH is %d.",
+				hdr.ErrLength, common.MAX_HRPC_ERROR_LENGTH))
+		}
+		buf := make([]byte, hdr.ErrLength)
+		var nread int
+		nread, err = cdc.rwc.Read(buf)
+		if uint32(nread) != hdr.ErrLength {
+			return errors.New(fmt.Sprintf("Error reading response header: "+
+				"failed to read %d bytes of error message.", nread))
+		}
+		if err != nil {
+			return errors.New(fmt.Sprintf("Error reading response header: "+
+				"failed to read %d bytes of error message: %s",
+				nread, err.Error()))
+		}
+		resp.Error = string(buf)
+	} else {
+		resp.Error = ""
+	}
+	cdc.length = hdr.Length
+	return nil
+}
+
+func (cdc *HrpcClientCodec) ReadResponseBody(body interface{}) error {
+	mh := new(codec.MsgpackHandle)
+	mh.WriteExt = true
+	dec := codec.NewDecoder(io.LimitReader(cdc.rwc, int64(cdc.length)), mh)
+	err := dec.Decode(body)
+	if err != nil {
+		return errors.New(fmt.Sprintf("Failed to read response body: %s",
+			err.Error()))
+	}
+	return nil
+}
+
+func (cdc *HrpcClientCodec) Close() error {
+	return cdc.rwc.Close()
+}
+
+func newHClient(hrpcAddr string) (*hClient, error) {
+	hcr := hClient{}
+	conn, err := net.Dial("tcp", hrpcAddr)
+	if err != nil {
+		return nil, errors.New(fmt.Sprintf("Error contacting the HRPC server "+
+			"at %s: %s", hrpcAddr, err.Error()))
+	}
+	hcr.rpcClient = rpc.NewClientWithCodec(&HrpcClientCodec{rwc: conn})
+	return &hcr, nil
+}
+
+func (hcr *hClient) writeSpans(req *common.WriteSpansReq) error {
+	resp := common.WriteSpansResp{}
+	return hcr.rpcClient.Call(common.METHOD_NAME_WRITE_SPANS, req, &resp)
+}
+
+func (hcr *hClient) Close() {
+	hcr.rpcClient.Close()
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/log.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/log.go b/htrace-htraced/go/src/org/apache/htrace/common/log.go
new file mode 100644
index 0000000..305ecf3
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/log.go
@@ -0,0 +1,296 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"errors"
+	"fmt"
+	"org/apache/htrace/conf"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+// A logSink is a place logs can be written to.
+type logSink struct {
+	path     logPath
+	file     *os.File
+	lock     sync.Mutex
+	refCount int // protected by logFilesLock
+}
+
+// Write to the logSink.
+func (sink *logSink) write(str string) {
+	sink.lock.Lock()
+	defer sink.lock.Unlock()
+	_, err := sink.file.Write([]byte(str))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error logging to '%s': %s\n", sink.path, err.Error())
+	}
+}
+
+// Unreference the logSink.  If there are no more references, and the logSink is
+// closeable, then we will close it here.
+func (sink *logSink) Unref() {
+	logFilesLock.Lock()
+	defer logFilesLock.Unlock()
+	sink.refCount--
+	if sink.refCount <= 0 {
+		if sink.path.IsCloseable() {
+			err := sink.file.Close()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error closing log file %s: %s\n",
+					sink.path, err.Error())
+			}
+		}
+		logSinks[sink.path] = nil
+	}
+}
+
+type logPath string
+
+// An empty LogPath represents "stdout."
+const STDOUT_LOG_PATH = ""
+
+// Convert a path to a logPath.
+func logPathFromString(path string) logPath {
+	if path == STDOUT_LOG_PATH {
+		return logPath("")
+	}
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to get absolute path of %s: %s\n",
+			path, err.Error())
+		return logPath(path)
+	}
+	return logPath(absPath)
+}
+
+// Convert the path to a human-readable string.
+func (path logPath) String() string {
+	if path == "" {
+		return "(stdout)"
+	} else {
+		return string(path)
+	}
+}
+
+// Return true if the path is closeable.  stdout is not closeable.
+func (path logPath) IsCloseable() bool {
+	return path != STDOUT_LOG_PATH
+}
+
+func (path logPath) Open() *logSink {
+	if path == STDOUT_LOG_PATH {
+		return &logSink{path: path, file: os.Stdout}
+	}
+	file, err := os.OpenFile(string(path), os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		sink := &logSink{path: STDOUT_LOG_PATH, file: os.Stdout}
+		fmt.Fprintf(os.Stderr, "Failed to open log file %s: %s\n",
+			path, err.Error())
+		return sink
+	}
+	return &logSink{path: path, file: file}
+}
+
+var logFilesLock sync.Mutex
+
+var logSinks map[logPath]*logSink = make(map[logPath]*logSink)
+
+func getOrCreateLogSink(pathStr string) *logSink {
+	path := logPathFromString(pathStr)
+	logFilesLock.Lock()
+	defer logFilesLock.Unlock()
+	sink := logSinks[path]
+	if sink == nil {
+		sink = path.Open()
+		logSinks[path] = sink
+	}
+	sink.refCount++
+	return sink
+}
+
+type Level int
+
+const (
+	TRACE Level = iota
+	DEBUG
+	INFO
+	WARN
+	ERROR
+)
+
+var levelToString map[Level]string = map[Level]string{
+	TRACE: "TRACE",
+	DEBUG: "DEBUG",
+	INFO:  "INFO",
+	WARN:  "WARN",
+	ERROR: "ERROR",
+}
+
+func (level Level) String() string {
+	return levelToString[level]
+}
+
+func (level Level) LogString() string {
+	return level.String()[0:1]
+}
+
+func LevelFromString(str string) (Level, error) {
+	for k, v := range levelToString {
+		if strings.ToLower(v) == strings.ToLower(str) {
+			return k, nil
+		}
+	}
+	var levelNames sort.StringSlice
+	levelNames = make([]string, len(levelToString))
+	var i int
+	for _, v := range levelToString {
+		levelNames[i] = v
+		i++
+	}
+	sort.Sort(levelNames)
+	return TRACE, errors.New(fmt.Sprintf("No such level as '%s'.  Valid "+
+		"levels are '%v'\n", str, levelNames))
+}
+
+type Logger struct {
+	sink  *logSink
+	Level Level
+}
+
+func NewLogger(faculty string, cnf *conf.Config) *Logger {
+	path, level := parseConf(faculty, cnf)
+	sink := getOrCreateLogSink(path)
+	return &Logger{sink: sink, Level: level}
+}
+
+func parseConf(faculty string, cnf *conf.Config) (string, Level) {
+	facultyLogPathKey := faculty + "." + conf.HTRACE_LOG_PATH
+	var facultyLogPath string
+	if cnf.Contains(facultyLogPathKey) {
+		facultyLogPath = cnf.Get(facultyLogPathKey)
+	} else {
+		facultyLogPath = cnf.Get(conf.HTRACE_LOG_PATH)
+	}
+	facultyLogLevelKey := faculty + conf.HTRACE_LOG_LEVEL
+	var facultyLogLevelStr string
+	if cnf.Contains(facultyLogLevelKey) {
+		facultyLogLevelStr = cnf.Get(facultyLogLevelKey)
+	} else {
+		facultyLogLevelStr = cnf.Get(conf.HTRACE_LOG_LEVEL)
+	}
+	level, err := LevelFromString(facultyLogLevelStr)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error configuring log level: %s.  Using TRACE.\n")
+		level = TRACE
+	}
+	return facultyLogPath, level
+}
+
+func (lg *Logger) Trace(str string) {
+	lg.Write(TRACE, str)
+}
+
+func (lg *Logger) Tracef(format string, v ...interface{}) {
+	lg.Write(TRACE, fmt.Sprintf(format, v...))
+}
+
+func (lg *Logger) Debug(str string) {
+	lg.Write(DEBUG, str)
+}
+
+func (lg *Logger) Debugf(format string, v ...interface{}) {
+	lg.Write(DEBUG, fmt.Sprintf(format, v...))
+}
+
+func (lg *Logger) Info(str string) {
+	lg.Write(INFO, str)
+}
+
+func (lg *Logger) Infof(format string, v ...interface{}) {
+	lg.Write(INFO, fmt.Sprintf(format, v...))
+}
+
+func (lg *Logger) Warn(str string) error {
+	lg.Write(WARN, str)
+	return errors.New(str)
+}
+
+func (lg *Logger) Warnf(format string, v ...interface{}) error {
+	str := fmt.Sprintf(format, v...)
+	lg.Write(WARN, str)
+	return errors.New(str)
+}
+
+func (lg *Logger) Error(str string) error {
+	lg.Write(ERROR, str)
+	return errors.New(str)
+}
+
+func (lg *Logger) Errorf(format string, v ...interface{}) error {
+	str := fmt.Sprintf(format, v...)
+	lg.Write(ERROR, str)
+	return errors.New(str)
+}
+
+func (lg *Logger) Write(level Level, str string) {
+	if level >= lg.Level {
+		lg.sink.write(time.Now().Format(time.RFC3339) + " " +
+			level.LogString() + ": " + str)
+	}
+}
+
+//
+// A few functions which can be used to determine if a certain level of tracing
+// is enabled.  These are useful in situations when evaluating the parameters
+// of a logging function is expensive.  (Note, however, that we don't pay the
+// cost of string concatenation and manipulation when a log message doesn't
+// trigger.)
+//
+
+func (lg *Logger) TraceEnabled() bool {
+	return lg.Level >= TRACE
+}
+
+func (lg *Logger) DebugEnabled() bool {
+	return lg.Level >= DEBUG
+}
+
+func (lg *Logger) InfoEnabled() bool {
+	return lg.Level >= INFO
+}
+
+func (lg *Logger) WarnEnabled() bool {
+	return lg.Level >= WARN
+}
+
+func (lg *Logger) ErrorEnabled() bool {
+	return lg.Level >= ERROR
+}
+
+func (lg *Logger) Close() {
+	lg.sink.Unref()
+	lg.sink = nil
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/log_test.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/log_test.go b/htrace-htraced/go/src/org/apache/htrace/common/log_test.go
new file mode 100644
index 0000000..b415ce2
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/log_test.go
@@ -0,0 +1,122 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"org/apache/htrace/conf"
+	"os"
+	"strings"
+	"testing"
+)
+
+func newLogger(faculty string, args ...string) *Logger {
+	cnfBld := conf.Builder{Defaults: conf.DEFAULTS}
+	cnf, err := cnfBld.Build()
+	if err != nil {
+		panic(fmt.Sprintf("failed to create conf: %s", err.Error()))
+	}
+	cnf2 := cnf.Clone(args...)
+	lg := NewLogger(faculty, cnf2)
+	return lg
+}
+
+func TestNewLogger(t *testing.T) {
+	lg := newLogger("foo", "log.level", "TRACE")
+	lg.Close()
+}
+
+func verifyLines(t *testing.T, rdr io.Reader, lines []string) {
+	scanner := bufio.NewScanner(rdr)
+	lineIdx := 0
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, lines[lineIdx]) {
+			t.Fatalf("Error on line %d: didn't find substring '%s' in line '%s'\n",
+				(lineIdx + 1), lines[lineIdx], line)
+		}
+		lineIdx++
+	}
+	if err := scanner.Err(); err != nil {
+		t.Fatal(err.Error())
+	}
+}
+
+func TestFileLogs(t *testing.T) {
+	tempDir, err := ioutil.TempDir(os.TempDir(), "testFileLogs")
+	if err != nil {
+		panic(fmt.Sprintf("error creating tempdir: %s\n", err.Error()))
+	}
+	defer os.RemoveAll(tempDir)
+	logPath := tempDir + conf.PATH_SEP + "log"
+	lg := newLogger("foo", "log.level", "DEBUG",
+		"foo.log.level", "INFO",
+		"log.path", logPath)
+	lg.Tracef("Non-important stuff, ignore this.\n")
+	lg.Infof("problem with the foobar\n")
+	lg.Tracef("More non-important stuff, also ignore this.\n")
+	lg.Infof("and another problem with the foobar\n")
+	logFile, err := os.Open(logPath)
+	if err != nil {
+		t.Fatalf("failed to open file %s: %s\n", logPath, err.Error())
+	}
+	verifyLines(t, logFile, []string{
+		"problem with the foobar",
+		"and another problem with the foobar",
+	})
+	logFile.Close()
+	lg.Close()
+}
+
+func TestMultipleFileLogs(t *testing.T) {
+	tempDir, err := ioutil.TempDir(os.TempDir(), "testMultipleFileLogs")
+	if err != nil {
+		panic(fmt.Sprintf("error creating tempdir: %s\n", err.Error()))
+	}
+	defer os.RemoveAll(tempDir)
+	logPath := tempDir + conf.PATH_SEP + "log"
+	fooLg := newLogger("foo", "log.level", "DEBUG",
+		"foo.log.level", "INFO",
+		"log.path", logPath)
+	fooLg.Infof("The foo needs maintenance.\n")
+	barLg := newLogger("bar", "log.level", "DEBUG",
+		"foo.log.level", "INFO",
+		"log.path", logPath)
+	barLg.Debugf("The bar is open\n")
+	fooLg.Errorf("Fizz buzz\n")
+	logFile, err := os.Open(logPath)
+	if err != nil {
+		t.Fatalf("failed to open file %s: %s\n", logPath, err.Error())
+	}
+	fooLg.Tracef("Fizz buzz2\n")
+	barLg.Tracef("Fizz buzz3\n")
+	verifyLines(t, logFile, []string{
+		"The foo needs maintenance.",
+		"The bar is open",
+		"Fizz buzz",
+		"Fizz buzz3",
+	})
+	logFile.Close()
+	fooLg.Close()
+	barLg.Close()
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/process.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/process.go b/htrace-htraced/go/src/org/apache/htrace/common/process.go
new file mode 100644
index 0000000..d138178
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/process.go
@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"bufio"
+	"org/apache/htrace/conf"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func LoadApplicationConfig() *conf.Config {
+	cnf, dlog := conf.LoadApplicationConfig()
+	lg := NewLogger("conf", cnf)
+	defer lg.Close()
+	if lg.Level <= DEBUG {
+		// Print out the debug information from loading the configuration.
+		scanner := bufio.NewScanner(dlog)
+		for scanner.Scan() {
+			lg.Debugf(scanner.Text() + "\n")
+		}
+	}
+	return cnf
+}
+
+func InstallSignalHandlers(cnf *conf.Config) {
+	fatalSigs := []os.Signal{
+		os.Interrupt,
+		os.Kill,
+		syscall.SIGINT,
+		syscall.SIGABRT,
+		syscall.SIGALRM,
+		syscall.SIGBUS,
+		syscall.SIGFPE,
+		syscall.SIGILL,
+		syscall.SIGQUIT,
+		syscall.SIGSEGV,
+		syscall.SIGTERM,
+	}
+	sigChan := make(chan os.Signal, len(fatalSigs))
+	signal.Notify(sigChan, fatalSigs...)
+	lg := NewLogger("exit", cnf)
+	go func() {
+		sig := <-sigChan
+		lg.Errorf("Terminating on signal: %v\n", sig)
+		lg.Close()
+		os.Exit(1)
+	}()
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/query.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/query.go b/htrace-htraced/go/src/org/apache/htrace/common/query.go
new file mode 100644
index 0000000..8c9128f
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/query.go
@@ -0,0 +1,126 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"encoding/json"
+)
+
+//
+// Represents queries that can be sent to htraced.
+//
+// Each query consists of set of predicates that will be 'AND'ed together to
+// return a set of spans.  Predicates contain an operation, a field, and a
+// value.
+//
+// For example, a query might be "return the first 100 spans between 5:00pm
+// and 5:01pm"  This query would have two predicates: time greater than or
+// equal to 5:00pm, and time less than or equal to 5:01pm.
+// In HTrace, times are always expressed in milliseconds since the Epoch.
+// So this would become:
+// { "lim" : 100, "pred" : [
+//   { "op" : "ge", "field" : "begin", "val" : 1234 },
+//   { "op" : "le", "field" : "begin", "val" : 5678 },
+// ] }
+//
+// Where '1234' and '5678' were replaced by times since the epoch in
+// milliseconds.
+//
+
+type Op string
+
+const (
+	CONTAINS               Op = "cn"
+	EQUALS                 Op = "eq"
+	LESS_THAN_OR_EQUALS    Op = "le"
+	GREATER_THAN_OR_EQUALS Op = "ge"
+	GREATER_THAN           Op = "gt"
+)
+
+func (op Op) IsDescending() bool {
+	return op == LESS_THAN_OR_EQUALS
+}
+
+func (op Op) IsValid() bool {
+	ops := ValidOps()
+	for i := range ops {
+		if ops[i] == op {
+			return true
+		}
+	}
+	return false
+}
+
+func ValidOps() []Op {
+	return []Op{CONTAINS, EQUALS, LESS_THAN_OR_EQUALS, GREATER_THAN_OR_EQUALS,
+		GREATER_THAN}
+}
+
+type Field string
+
+const (
+	SPAN_ID     Field = "spanid"
+	DESCRIPTION Field = "description"
+	BEGIN_TIME  Field = "begin"
+	END_TIME    Field = "end"
+	DURATION    Field = "duration"
+)
+
+func (field Field) IsValid() bool {
+	fields := ValidFields()
+	for i := range fields {
+		if fields[i] == field {
+			return true
+		}
+	}
+	return false
+}
+
+func ValidFields() []Field {
+	return []Field{SPAN_ID, DESCRIPTION, BEGIN_TIME, END_TIME, DURATION}
+}
+
+type Predicate struct {
+	Op    Op     `json:"op"`
+	Field Field  `json:"field"`
+	Val   string `val:"val"`
+}
+
+func (pred *Predicate) String() string {
+	buf, err := json.Marshal(pred)
+	if err != nil {
+		panic(err)
+	}
+	return string(buf)
+}
+
+type Query struct {
+	Predicates []Predicate `json:"pred"`
+	Lim        int         `json:"lim"`
+	Prev       *Span       `json:"prev"`
+}
+
+func (query *Query) String() string {
+	buf, err := json.Marshal(query)
+	if err != nil {
+		panic(err)
+	}
+	return string(buf)
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/query_test.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/query_test.go b/htrace-htraced/go/src/org/apache/htrace/common/query_test.go
new file mode 100644
index 0000000..2697d9c
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/query_test.go
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"testing"
+)
+
+func TestValidOps(t *testing.T) {
+	for i := range ValidOps() {
+		op := ValidOps()[i]
+		if !op.IsValid() {
+			t.Fatalf("op %s was in ValidOps, but IsValid returned false.\n", op)
+		}
+	}
+	invalidOp := Op("completelybogus")
+	if invalidOp.IsValid() {
+		t.Fatalf("op %s was invalid, but IsValid returned true.\n", invalidOp)
+	}
+}
+
+func TestValidFields(t *testing.T) {
+	for i := range ValidFields() {
+		field := ValidFields()[i]
+		if !field.IsValid() {
+			t.Fatalf("field %s was in ValidFields, but IsValid returned false.\n", field)
+		}
+	}
+	invalidField := Field("completelybogus")
+	if invalidField.IsValid() {
+		t.Fatalf("field %s was invalid, but IsValid returned true.\n", invalidField)
+	}
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/rest.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/rest.go b/htrace-htraced/go/src/org/apache/htrace/common/rest.go
new file mode 100644
index 0000000..b898ca4
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/rest.go
@@ -0,0 +1,29 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+// Info returned by /server/info
+type ServerInfo struct {
+	// The server release version.
+	ReleaseVersion string
+
+	// The git hash that this software was built with.
+	GitVersion string
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/rpc.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/rpc.go b/htrace-htraced/go/src/org/apache/htrace/common/rpc.go
new file mode 100644
index 0000000..fe50a44
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/rpc.go
@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+// The 4-byte magic number which is sent first in the HRPC header
+const HRPC_MAGIC = 0x43525448
+
+// Method ID codes.  Do not reorder these.
+const (
+	METHOD_ID_NONE        = 0
+	METHOD_ID_WRITE_SPANS = iota
+)
+
+const METHOD_NAME_WRITE_SPANS = "HrpcHandler.WriteSpans"
+
+// Maximum length of the error message passed in an HRPC response
+const MAX_HRPC_ERROR_LENGTH = 4 * 1024 * 1024
+
+// Maximum length of HRPC message body
+const MAX_HRPC_BODY_LENGTH = 64 * 1024 * 1024
+
+// A request to write spans to htraced.
+type WriteSpansReq struct {
+	DefaultPid string
+	Spans      []*Span
+}
+
+// A response to a WriteSpansReq
+type WriteSpansResp struct {
+}
+
+// The header which is sent over the wire for HRPC
+type HrpcRequestHeader struct {
+	Magic    uint32
+	MethodId uint32
+	Seq      uint64
+	Length   uint32
+}
+
+// The response which is sent over the wire for HRPC
+type HrpcResponseHeader struct {
+	Seq       uint64
+	MethodId  uint32
+	ErrLength uint32
+	Length    uint32
+}
+
+func HrpcMethodIdToMethodName(id uint32) string {
+	switch id {
+	case METHOD_ID_WRITE_SPANS:
+		return METHOD_NAME_WRITE_SPANS
+	default:
+		return ""
+	}
+}
+
+func HrpcMethodNameToId(name string) uint32 {
+	switch name {
+	case METHOD_NAME_WRITE_SPANS:
+		return METHOD_ID_WRITE_SPANS
+	default:
+		return METHOD_ID_NONE
+	}
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/span.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/span.go b/htrace-htraced/go/src/org/apache/htrace/common/span.go
new file mode 100644
index 0000000..b276844
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/span.go
@@ -0,0 +1,140 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+//
+// Represents a trace span.
+//
+// Compatibility notes:
+// When converting to JSON, we store the 64-bit numbers as hexadecimal strings rather than as
+// integers.  This is because JavaScript lacks the ability to handle 64-bit integers.  Numbers above
+// about 55 bits will be rounded by Javascript.  Since the Javascript UI is a primary consumer of
+// this JSON data, we have to simply pass it as a string.
+//
+
+type TraceInfoMap map[string]string
+
+type TimelineAnnotation struct {
+	Time int64  `json:"t"`
+	Msg  string `json:"m"`
+}
+
+type SpanId uint64
+
+func (id SpanId) String() string {
+	return fmt.Sprintf("%016x", uint64(id))
+}
+
+func (id SpanId) Val() uint64 {
+	return uint64(id)
+}
+
+func (id SpanId) MarshalJSON() ([]byte, error) {
+	return []byte(`"` + fmt.Sprintf("%016x", uint64(id)) + `"`), nil
+}
+
+type SpanSlice []*Span
+
+func (s SpanSlice) Len() int {
+	return len(s)
+}
+
+func (s SpanSlice) Less(i, j int) bool {
+	return s[i].Id < s[j].Id
+}
+
+func (s SpanSlice) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+type SpanIdSlice []SpanId
+
+func (s SpanIdSlice) Len() int {
+	return len(s)
+}
+
+func (s SpanIdSlice) Less(i, j int) bool {
+	return s[i] < s[j]
+}
+
+func (s SpanIdSlice) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+const DOUBLE_QUOTE = 0x22
+
+func (id *SpanId) UnmarshalJSON(b []byte) error {
+	if b[0] != DOUBLE_QUOTE {
+		return errors.New("Expected spanID to start with a string quote.")
+	}
+	if b[len(b)-1] != DOUBLE_QUOTE {
+		return errors.New("Expected spanID to end with a string quote.")
+	}
+	return id.FromString(string(b[1 : len(b)-1]))
+}
+
+func (id *SpanId) FromString(str string) error {
+	v, err := strconv.ParseUint(str, 16, 64)
+	if err != nil {
+		return err
+	}
+	*id = SpanId(v)
+	return nil
+}
+
+type SpanData struct {
+	Begin               int64                `json:"b"`
+	End                 int64                `json:"e"`
+	Description         string               `json:"d"`
+	TraceId             SpanId               `json:"i"`
+	Parents             []SpanId             `json:"p"`
+	Info                TraceInfoMap         `json:"n,omitempty"`
+	ProcessId           string               `json:"r"`
+	TimelineAnnotations []TimelineAnnotation `json:"t,omitempty"`
+}
+
+type Span struct {
+	Id SpanId `json:"s"`
+	SpanData
+}
+
+func (span *Span) ToJson() []byte {
+	jbytes, err := json.Marshal(*span)
+	if err != nil {
+		panic(err)
+	}
+	return jbytes
+}
+
+func (span *Span) String() string {
+	return string(span.ToJson())
+}
+
+// Compute the span duration.  We ignore overflow since we never deal with negative times.
+func (span *Span) Duration() int64 {
+	return span.End - span.Begin
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/span_test.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/span_test.go b/htrace-htraced/go/src/org/apache/htrace/common/span_test.go
new file mode 100644
index 0000000..f218b3a
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/span_test.go
@@ -0,0 +1,66 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"testing"
+)
+
+func TestSpanToJson(t *testing.T) {
+	t.Parallel()
+	span := Span{Id: 2305843009213693952,
+		SpanData: SpanData{
+			Begin:       123,
+			End:         456,
+			Description: "getFileDescriptors",
+			TraceId:     999,
+			Parents:     []SpanId{},
+			ProcessId:   "testProcessId",
+		}}
+	ExpectStrEqual(t,
+		`{"s":"2000000000000000","b":123,"e":456,"d":"getFileDescriptors","i":"00000000000003e7","p":[],"r":"testProcessId"}`,
+		string(span.ToJson()))
+}
+
+func TestAnnotatedSpanToJson(t *testing.T) {
+	t.Parallel()
+	span := Span{Id: 1305813009213693952,
+		SpanData: SpanData{
+			Begin:       1234,
+			End:         4567,
+			Description: "getFileDescriptors2",
+			TraceId:     999,
+			Parents:     []SpanId{},
+			ProcessId:   "testAnnotatedProcessId",
+			TimelineAnnotations: []TimelineAnnotation{
+				TimelineAnnotation{
+					Time: 7777,
+					Msg:  "contactedServer",
+				},
+				TimelineAnnotation{
+					Time: 8888,
+					Msg:  "passedFd",
+				},
+			},
+		}}
+	ExpectStrEqual(t,
+		`{"s":"121f2e036d442000","b":1234,"e":4567,"d":"getFileDescriptors2","i":"00000000000003e7","p":[],"r":"testAnnotatedProcessId","t":[{"t":7777,"m":"contactedServer"},{"t":8888,"m":"passedFd"}]}`,
+		string(span.ToJson()))
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/common/test_util.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/common/test_util.go b/htrace-htraced/go/src/org/apache/htrace/common/test_util.go
new file mode 100644
index 0000000..871c847
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/common/test_util.go
@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package common
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+type Int64Slice []int64
+
+func (p Int64Slice) Len() int           { return len(p) }
+func (p Int64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p Int64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+type SupplierFun func() bool
+
+//
+// Wait for a configurable amount of time for a precondition to become true.
+//
+// Example:
+//   WaitFor(time.Minute * 1, time.Millisecond * 1, func() bool {
+//      return ht.Store.GetStatistics().NumSpansWritten >= 3
+//  })
+//
+func WaitFor(dur time.Duration, poll time.Duration, fun SupplierFun) {
+	if poll == 0 {
+		poll = dur / 10
+	}
+	if poll <= 0 {
+		panic("Can't have a polling time less than zero.")
+	}
+	endTime := time.Now().Add(dur)
+	for {
+		if fun() {
+			return
+		}
+		if !time.Now().Before(endTime) {
+			break
+		}
+		time.Sleep(poll)
+	}
+	panic(fmt.Sprintf("Timed out after %s", dur))
+}
+
+// Trigger a test failure if two strings are not equal.
+func ExpectStrEqual(t *testing.T, expect string, actual string) {
+	if expect != actual {
+		t.Fatalf("Expected:\n%s\nGot:\n%s\n", expect, actual)
+	}
+}
+
+// Trigger a test failure if the JSON representation of two spans are not equals.
+func ExpectSpansEqual(t *testing.T, spanA *Span, spanB *Span) {
+	ExpectStrEqual(t, string(spanA.ToJson()), string(spanB.ToJson()))
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/conf/config.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/conf/config.go b/htrace-htraced/go/src/org/apache/htrace/conf/config.go
new file mode 100644
index 0000000..6093649
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/conf/config.go
@@ -0,0 +1,266 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package conf
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+)
+
+//
+// The configuration code for HTraced.
+//
+// HTraced can be configured via Hadoop-style XML configuration files, or by passing -Dkey=value
+// command line arguments.  Command-line arguments without an equals sign, such as "-Dkey", will be
+// treated as setting the key to "true".
+//
+// Configuration key constants should be defined in config_keys.go.  Each key should have a default,
+// which will be used if the user supplies no value, or supplies an invalid value.
+// For that reason, it is not necessary for the Get, GetInt, etc. functions to take a default value
+// argument.
+//
+// Configuration objects are immutable.  However, you can make a copy of a configuration which adds
+// some changes using Configuration#Clone().
+//
+
+type Config struct {
+	settings map[string]string
+	defaults map[string]string
+}
+
+type Builder struct {
+	// If non-nil, the XML configuration file to read.
+	Reader io.Reader
+
+	// If non-nil, the configuration values to use.
+	Values map[string]string
+
+	// If non-nil, the default configuration values to use.
+	Defaults map[string]string
+
+	// If non-nil, the command-line arguments to use.
+	Argv []string
+}
+
+func getHTracedConfDirs(dlog io.Writer) []string {
+	confDir := os.Getenv("HTRACED_CONF_DIR")
+	io.WriteString(dlog, fmt.Sprintf("HTRACED_CONF_DIR=%s\n", confDir))
+	paths := filepath.SplitList(confDir)
+	if len(paths) < 1 {
+		return []string{"."}
+	}
+	return paths
+}
+
+// Load a configuration from the application's argv, configuration file, and the standard
+// defaults.
+func LoadApplicationConfig() (*Config, io.Reader) {
+	dlog := new(bytes.Buffer)
+	reader := openFile(CONFIG_FILE_NAME, getHTracedConfDirs(dlog), dlog)
+	bld := Builder{}
+	if reader != nil {
+		defer reader.Close()
+		bld.Reader = bufio.NewReader(reader)
+	}
+	bld.Argv = os.Args[1:]
+	bld.Defaults = DEFAULTS
+	cnf, err := bld.Build()
+	if err != nil {
+		log.Fatal("Error building configuration: " + err.Error())
+	}
+	os.Args = append(os.Args[0:1], bld.Argv...)
+	keys := make(sort.StringSlice, 0, 20)
+	for k, _ := range cnf.settings {
+		keys = append(keys, k)
+	}
+	sort.Sort(keys)
+	for i := range keys {
+		io.WriteString(dlog, fmt.Sprintf("%s = %s\n",
+			keys[i], cnf.settings[keys[i]]))
+	}
+	return cnf, dlog
+}
+
+// Attempt to open a configuration file somewhere on the provided list of paths.
+func openFile(cnfName string, paths []string, dlog io.Writer) io.ReadCloser {
+	for p := range paths {
+		path := fmt.Sprintf("%s%c%s", paths[p], os.PathSeparator, cnfName)
+		file, err := os.Open(path)
+		if err == nil {
+			io.WriteString(dlog, fmt.Sprintf("Reading configuration from %s.\n", path))
+			return file
+		}
+		if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOENT {
+			continue
+		}
+		io.WriteString(dlog, fmt.Sprintf("Error opening %s for read: %s\n", path, err.Error()))
+	}
+	return nil
+}
+
+// Try to parse a command-line element as a key=value pair.
+func parseAsConfigFlag(flag string) (string, string) {
+	var confPart string
+	if strings.HasPrefix(flag, "-D") {
+		confPart = flag[2:]
+	} else if strings.HasPrefix(flag, "--D") {
+		confPart = flag[3:]
+	} else {
+		return "", ""
+	}
+	if len(confPart) == 0 {
+		return "", ""
+	}
+	idx := strings.Index(confPart, "=")
+	if idx == -1 {
+		return confPart, "true"
+	}
+	return confPart[0:idx], confPart[idx+1:]
+}
+
+// Build a new configuration object from the provided conf.Builder.
+func (bld *Builder) Build() (*Config, error) {
+	// Load values and defaults
+	cnf := Config{}
+	cnf.settings = make(map[string]string)
+	if bld.Values != nil {
+		for k, v := range bld.Values {
+			cnf.settings[k] = v
+		}
+	}
+	cnf.defaults = make(map[string]string)
+	if bld.Defaults != nil {
+		for k, v := range bld.Defaults {
+			cnf.defaults[k] = v
+		}
+	}
+
+	// Process the configuration file, if we have one
+	if bld.Reader != nil {
+		parseXml(bld.Reader, cnf.settings)
+	}
+
+	// Process command line arguments
+	var i int
+	for i < len(bld.Argv) {
+		str := bld.Argv[i]
+		key, val := parseAsConfigFlag(str)
+		if key != "" {
+			if val == "" {
+				cnf.settings[key] = "true"
+			} else {
+				cnf.settings[key] = val
+			}
+			bld.Argv = append(bld.Argv[:i], bld.Argv[i+1:]...)
+		} else {
+			i++
+		}
+	}
+	return &cnf, nil
+}
+
+// Returns true if the configuration has a non-default value for the given key.
+func (cnf *Config) Contains(key string) bool {
+	_, ok := cnf.settings[key]
+	return ok
+}
+
+// Get a string configuration key.
+func (cnf *Config) Get(key string) string {
+	ret := cnf.settings[key]
+	if ret != "" {
+		return ret
+	}
+	return cnf.defaults[key]
+}
+
+// Get a boolean configuration key.
+func (cnf *Config) GetBool(key string) bool {
+	str := cnf.settings[key]
+	ret, err := strconv.ParseBool(str)
+	if err == nil {
+		return ret
+	}
+	str = cnf.defaults[key]
+	ret, err = strconv.ParseBool(str)
+	if err == nil {
+		return ret
+	}
+	return false
+}
+
+// Get an integer configuration key.
+func (cnf *Config) GetInt(key string) int {
+	str := cnf.settings[key]
+	ret, err := strconv.Atoi(str)
+	if err == nil {
+		return ret
+	}
+	str = cnf.defaults[key]
+	ret, err = strconv.Atoi(str)
+	if err == nil {
+		return ret
+	}
+	return 0
+}
+
+// Get an int64 configuration key.
+func (cnf *Config) GetInt64(key string) int64 {
+	str := cnf.settings[key]
+	ret, err := strconv.ParseInt(str, 10, 64)
+	if err == nil {
+		return ret
+	}
+	str = cnf.defaults[key]
+	ret, err = strconv.ParseInt(str, 10, 64)
+	if err == nil {
+		return ret
+	}
+	return 0
+}
+
+// Make a deep copy of the given configuration.
+// Optionally, you can specify particular key/value pairs to change.
+// Example:
+// cnf2 := cnf.Copy("my.changed.key", "my.new.value")
+func (cnf *Config) Clone(args ...string) *Config {
+	if len(args)%2 != 0 {
+		panic("The arguments to Config#copy are key1, value1, " +
+			"key2, value2, and so on.  You must specify an even number of arguments.")
+	}
+	ncnf := &Config{defaults: cnf.defaults}
+	ncnf.settings = make(map[string]string)
+	for k, v := range cnf.settings {
+		ncnf.settings[k] = v
+	}
+	for i := 0; i < len(args); i += 2 {
+		ncnf.settings[args[i]] = args[i+1]
+	}
+	return ncnf
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/conf/config_keys.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/conf/config_keys.go b/htrace-htraced/go/src/org/apache/htrace/conf/config_keys.go
new file mode 100644
index 0000000..ccb09e0
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/conf/config_keys.go
@@ -0,0 +1,86 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package conf
+
+import (
+	"fmt"
+	"os"
+)
+
+//
+// Configuration keys for HTrace.
+//
+
+// The platform-specific path separator.  Usually slash.
+var PATH_SEP string = fmt.Sprintf("%c", os.PathSeparator)
+
+// The platform-specific path list separator.  Usually colon.
+var PATH_LIST_SEP string = fmt.Sprintf("%c", os.PathListSeparator)
+
+// The name of the XML configuration file to look for.
+const CONFIG_FILE_NAME = "htraced-conf.xml"
+
+// An environment variable containing a list of paths to search for the
+// configuration file in.
+const HTRACED_CONF_DIR = "HTRACED_CONF_DIR"
+
+// The web address to start the REST server on.
+const HTRACE_WEB_ADDRESS = "web.address"
+
+// The default port for the Htrace web address.
+const HTRACE_WEB_ADDRESS_DEFAULT_PORT = 9095
+
+// The web address to start the REST server on.
+const HTRACE_HRPC_ADDRESS = "hrpc.address"
+
+// The default port for the Htrace HRPC address.
+const HTRACE_HRPC_ADDRESS_DEFAULT_PORT = 9075
+
+// The directories to put the data store into.  Separated by PATH_LIST_SEP.
+const HTRACE_DATA_STORE_DIRECTORIES = "data.store.directories"
+
+// Boolean key which indicates whether we should clear data on startup.
+const HTRACE_DATA_STORE_CLEAR = "data.store.clear"
+
+// How many writes to buffer before applying backpressure to span senders.
+const HTRACE_DATA_STORE_SPAN_BUFFER_SIZE = "data.store.span.buffer.size"
+
+// Path to put the logs from htrace, or the empty string to use stdout.
+const HTRACE_LOG_PATH = "log.path"
+
+// The log level to use for the logs in htrace.
+const HTRACE_LOG_LEVEL = "log.level"
+
+// A host:port pair to send information to on startup.  This is used in unit
+// tests to determine the (random) port of the htraced process that has been
+// started.
+const HTRACE_STARTUP_NOTIFICATION_ADDRESS = "startup.notification.address"
+
+// Default values for HTrace configuration keys.
+var DEFAULTS = map[string]string{
+	HTRACE_WEB_ADDRESS:  fmt.Sprintf("0.0.0.0:%d", HTRACE_WEB_ADDRESS_DEFAULT_PORT),
+	HTRACE_HRPC_ADDRESS: fmt.Sprintf("0.0.0.0:%d", HTRACE_HRPC_ADDRESS_DEFAULT_PORT),
+	HTRACE_DATA_STORE_DIRECTORIES: PATH_SEP + "tmp" + PATH_SEP + "htrace1" +
+		PATH_LIST_SEP + PATH_SEP + "tmp" + PATH_SEP + "htrace2",
+	HTRACE_DATA_STORE_CLEAR:            "false",
+	HTRACE_DATA_STORE_SPAN_BUFFER_SIZE: "100",
+	HTRACE_LOG_PATH:                    "",
+	HTRACE_LOG_LEVEL:                   "INFO",
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/conf/config_test.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/conf/config_test.go b/htrace-htraced/go/src/org/apache/htrace/conf/config_test.go
new file mode 100644
index 0000000..42c1c71
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/conf/config_test.go
@@ -0,0 +1,138 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package conf
+
+import (
+	"bytes"
+	"os"
+	"strings"
+	"testing"
+)
+
+// Test that parsing command-line arguments of the form -Dfoo=bar works.
+func TestParseArgV(t *testing.T) {
+	t.Parallel()
+	argv := []string{"-Dfoo=bar", "-Dbaz=123", "-DsillyMode"}
+	bld := &Builder{Argv: argv}
+	cnf, err := bld.Build()
+	if err != nil {
+		t.Fatal()
+	}
+	if "bar" != cnf.Get("foo") {
+		t.Fatal()
+	}
+	if 123 != cnf.GetInt("baz") {
+		t.Fatal()
+	}
+	if !cnf.GetBool("sillyMode") {
+		t.Fatal()
+	}
+	if cnf.GetBool("otherSillyMode") {
+		t.Fatal()
+	}
+}
+
+// Test that default values work.
+// Defaults are used only when the configuration option is not present or can't be parsed.
+func TestDefaults(t *testing.T) {
+	t.Parallel()
+	argv := []string{"-Dfoo=bar", "-Dbaz=invalidNumber"}
+	defaults := map[string]string{
+		"foo":  "notbar",
+		"baz":  "456",
+		"foo2": "4611686018427387904",
+	}
+	bld := &Builder{Argv: argv, Defaults: defaults}
+	cnf, err := bld.Build()
+	if err != nil {
+		t.Fatal()
+	}
+	if "bar" != cnf.Get("foo") {
+		t.Fatal()
+	}
+	if 456 != cnf.GetInt("baz") {
+		t.Fatal()
+	}
+	if 4611686018427387904 != cnf.GetInt64("foo2") {
+		t.Fatal()
+	}
+}
+
+// Test that we can parse our XML configuration file.
+func TestXmlConfigurationFile(t *testing.T) {
+	t.Parallel()
+	xml := `
+<?xml version="1.0"?>
+<?xml-stylesheet type=\"text/xsl\" href=\"configuration.xsl\"?>
+<configuration>
+  <property>
+    <name>foo.bar</name>
+    <value>123</value>
+  </property>
+  <property>
+    <name>foo.baz</name>
+    <value>xmlValue</value>
+  </property>
+  <!--<property>
+    <name>commented.out</name>
+    <value>stuff</value>
+  </property>-->
+</configuration>
+`
+	xmlReader := strings.NewReader(xml)
+	argv := []string{"-Dfoo.bar=456"}
+	defaults := map[string]string{
+		"foo.bar":     "789",
+		"cmdline.opt": "4611686018427387904",
+	}
+	bld := &Builder{Argv: argv, Defaults: defaults, Reader: xmlReader}
+	cnf, err := bld.Build()
+	if err != nil {
+		t.Fatal()
+	}
+	// The command-line argument takes precedence over the XML and the defaults.
+	if 456 != cnf.GetInt("foo.bar") {
+		t.Fatal()
+	}
+	if "xmlValue" != cnf.Get("foo.baz") {
+		t.Fatalf("foo.baz = %s", cnf.Get("foo.baz"))
+	}
+	if "" != cnf.Get("commented.out") {
+		t.Fatal()
+	}
+	if 4611686018427387904 != cnf.GetInt64("cmdline.opt") {
+		t.Fatal()
+	}
+}
+
+// Test our handling of the HTRACE_CONF_DIR environment variable.
+func TestGetHTracedConfDirs(t *testing.T) {
+	os.Setenv("HTRACED_CONF_DIR", "")
+	dlog := new(bytes.Buffer)
+	dirs := getHTracedConfDirs(dlog)
+	if len(dirs) != 1 || dirs[0] != "." {
+		t.Fatal()
+	}
+	os.Setenv("HTRACED_CONF_DIR", "/foo/bar:/baz")
+	dirs = getHTracedConfDirs(dlog)
+	if len(dirs) != 2 || dirs[0] != "/foo/bar" || dirs[1] != "/baz" {
+		t.Fatal()
+	}
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/conf/xml.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/conf/xml.go b/htrace-htraced/go/src/org/apache/htrace/conf/xml.go
new file mode 100644
index 0000000..de14bc5
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/conf/xml.go
@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package conf
+
+import (
+	"encoding/xml"
+	"io"
+	"log"
+)
+
+type configuration struct {
+	Properties []propertyXml `xml:"property"`
+}
+
+type propertyXml struct {
+	Name  string `xml:"name"`
+	Value string `xml:"value"`
+}
+
+// Parse an XML configuration file.
+func parseXml(reader io.Reader, m map[string]string) error {
+	dec := xml.NewDecoder(reader)
+	configurationXml := configuration{}
+	err := dec.Decode(&configurationXml)
+	if err != nil {
+		return err
+	}
+	props := configurationXml.Properties
+	for p := range props {
+		key := props[p].Name
+		value := props[p].Value
+		if key == "" {
+			log.Println("Warning: ignoring element with missing or empty <name>.")
+			continue
+		}
+		if value == "" {
+			log.Println("Warning: ignoring element with key " + key + " with missing or empty <value>.")
+			continue
+		}
+		//log.Printf("setting %s to %s\n", key, value)
+		m[key] = value
+	}
+	return nil
+}

http://git-wip-us.apache.org/repos/asf/incubator-htrace/blob/42b2f6a2/htrace-htraced/go/src/org/apache/htrace/htrace/cmd.go
----------------------------------------------------------------------
diff --git a/htrace-htraced/go/src/org/apache/htrace/htrace/cmd.go b/htrace-htraced/go/src/org/apache/htrace/htrace/cmd.go
new file mode 100644
index 0000000..38cdb58
--- /dev/null
+++ b/htrace-htraced/go/src/org/apache/htrace/htrace/cmd.go
@@ -0,0 +1,317 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"github.com/alecthomas/kingpin"
+	"io"
+	htrace "org/apache/htrace/client"
+	"org/apache/htrace/common"
+	"org/apache/htrace/conf"
+	"os"
+	"time"
+)
+
+var RELEASE_VERSION string
+var GIT_VERSION string
+
+const EXIT_SUCCESS = 0
+const EXIT_FAILURE = 1
+
+var verbose *bool
+
+const USAGE = `The Apache HTrace command-line tool.  This tool retrieves and modifies settings and
+other data on a running htraced daemon.
+
+If we find an ` + conf.CONFIG_FILE_NAME + ` configuration file in the list of directories
+specified in ` + conf.HTRACED_CONF_DIR + `, we will use that configuration; otherwise, 
+the defaults will be used.
+`
+
+func main() {
+	// Load htraced configuration
+	cnf := common.LoadApplicationConfig()
+
+	// Parse argv
+	app := kingpin.New(os.Args[0], USAGE)
+	app.Flag("Dmy.key", "Set configuration key 'my.key' to 'my.value'.  Replace 'my.key' "+
+		"with any key you want to set.").Default("my.value").String()
+	addr := app.Flag("addr", "Server address.").String()
+	verbose = app.Flag("verbose", "Verbose.").Default("false").Bool()
+	version := app.Command("version", "Print the version of this program.")
+	serverInfo := app.Command("serverInfo", "Print information retrieved from an htraced server.")
+	findSpan := app.Command("findSpan", "Print information about a trace span with a given ID.")
+	findSpanId := findSpan.Arg("id", "Span ID to find. Example: 0x123456789abcdef").Required().Uint64()
+	findChildren := app.Command("findChildren", "Print out the span IDs that are children of a given span ID.")
+	parentSpanId := findChildren.Arg("id", "Span ID to print children for. Example: 0x123456789abcdef").
+		Required().Uint64()
+	childLim := findChildren.Flag("lim", "Maximum number of child IDs to print.").Default("20").Int()
+	loadFile := app.Command("loadFile", "Write whitespace-separated JSON spans from a file to the server.")
+	loadFilePath := loadFile.Arg("path",
+		"A file containing whitespace-separated span JSON.").Required().String()
+	loadJson := app.Command("load", "Write JSON spans from the command-line to the server.")
+	loadJsonArg := loadJson.Arg("json", "A JSON span to write to the server.").Required().String()
+	dumpAll := app.Command("dumpAll", "Dump all spans from the htraced daemon.")
+	dumpAllOutPath := dumpAll.Arg("path", "The path to dump the trace spans to.").Default("-").String()
+	dumpAllLim := dumpAll.Flag("lim", "The number of spans to transfer from the server at once.").
+		Default("100").Int()
+	graph := app.Command("graph", "Visualize span JSON as a graph.")
+	graphJsonFile := graph.Arg("input", "The JSON file to load").Required().String()
+	graphDotFile := graph.Flag("output",
+		"The path to write a GraphViz dotfile to.  This file can be used as input to "+
+			"GraphViz, in order to generate a pretty picture.  See graphviz.org for more "+
+			"information about generating pictures of graphs.").Default("-").String()
+	query := app.Command("query", "Send a query to htraced.")
+	queryLim := query.Flag("lim", "Maximum number of spans to retrieve.").Default("20").Int()
+	queryArg := query.Arg("query", "The query string to send.  Query strings have the format "+
+		"[TYPE] [OPERATOR] [CONST], joined by AND statements.").Required().String()
+	rawQuery := app.Command("rawQuery", "Send a raw JSON query to htraced.")
+	rawQueryArg := query.Arg("json", "The query JSON to send.").Required().String()
+	cmd := kingpin.MustParse(app.Parse(os.Args[1:]))
+
+	// Add the command-line settings into the configuration.
+	if *addr != "" {
+		cnf = cnf.Clone(conf.HTRACE_WEB_ADDRESS, *addr)
+	}
+
+	// Handle commands that don't require an HTrace client.
+	switch cmd {
+	case version.FullCommand():
+		os.Exit(printVersion())
+	case graph.FullCommand():
+		err := jsonSpanFileToDotFile(*graphJsonFile, *graphDotFile)
+		if err != nil {
+			fmt.Printf("graphing error: %s\n", err.Error())
+			os.Exit(EXIT_FAILURE)
+		}
+		os.Exit(EXIT_SUCCESS)
+	}
+
+	// Create HTrace client
+	hcl, err := htrace.NewClient(cnf)
+	if err != nil {
+		fmt.Printf("Failed to create HTrace client: %s\n", err.Error())
+		os.Exit(EXIT_FAILURE)
+	}
+
+	// Handle commands that require an HTrace client.
+	switch cmd {
+	case version.FullCommand():
+		os.Exit(printVersion())
+	case serverInfo.FullCommand():
+		os.Exit(printServerInfo(hcl))
+	case findSpan.FullCommand():
+		os.Exit(doFindSpan(hcl, common.SpanId(*findSpanId)))
+	case findChildren.FullCommand():
+		os.Exit(doFindChildren(hcl, common.SpanId(*parentSpanId), *childLim))
+	case loadJson.FullCommand():
+		os.Exit(doLoadSpanJson(hcl, *loadJsonArg))
+	case loadFile.FullCommand():
+		os.Exit(doLoadSpanJsonFile(hcl, *loadFilePath))
+	case dumpAll.FullCommand():
+		err := doDumpAll(hcl, *dumpAllOutPath, *dumpAllLim)
+		if err != nil {
+			fmt.Printf("dumpAll error: %s\n", err.Error())
+			os.Exit(EXIT_FAILURE)
+		}
+		os.Exit(EXIT_SUCCESS)
+	case query.FullCommand():
+		err := doQueryFromString(hcl, *queryArg, *queryLim)
+		if err != nil {
+			fmt.Printf("query error: %s\n", err.Error())
+			os.Exit(EXIT_FAILURE)
+		}
+		os.Exit(EXIT_SUCCESS)
+	case rawQuery.FullCommand():
+		err := doRawQuery(hcl, *rawQueryArg)
+		if err != nil {
+			fmt.Printf("raw query error: %s\n", err.Error())
+			os.Exit(EXIT_FAILURE)
+		}
+		os.Exit(EXIT_SUCCESS)
+	}
+
+	app.UsageErrorf(os.Stderr, "You must supply a command to run.")
+}
+
+// Print the version of the htrace binary.
+func printVersion() int {
+	fmt.Printf("Running htrace command version %s.\n", RELEASE_VERSION)
+	return EXIT_SUCCESS
+}
+
+// Print information retrieved from an htraced server via /server/info
+func printServerInfo(hcl *htrace.Client) int {
+	info, err := hcl.GetServerInfo()
+	if err != nil {
+		fmt.Println(err.Error())
+		return EXIT_FAILURE
+	}
+	fmt.Printf("HTraced server version %s (%s)\n", info.ReleaseVersion, info.GitVersion)
+	return EXIT_SUCCESS
+}
+
+// Print information about a trace span.
+func doFindSpan(hcl *htrace.Client, sid common.SpanId) int {
+	span, err := hcl.FindSpan(sid)
+	if err != nil {
+		fmt.Println(err.Error())
+		return EXIT_FAILURE
+	}
+	if span == nil {
+		fmt.Printf("Span ID not found.\n")
+		return EXIT_FAILURE
+	}
+	pbuf, err := json.MarshalIndent(span, "", "  ")
+	if err != nil {
+		fmt.Printf("Error: error pretty-printing span to JSON: %s\n", err.Error())
+		return EXIT_FAILURE
+	}
+	fmt.Printf("%s\n", string(pbuf))
+	return EXIT_SUCCESS
+}
+
+func doLoadSpanJsonFile(hcl *htrace.Client, spanFile string) int {
+	if spanFile == "" {
+		fmt.Printf("You must specify the json file to load.\n")
+		return EXIT_FAILURE
+	}
+	file, err := OpenInputFile(spanFile)
+	if err != nil {
+		fmt.Printf("Failed to open %s: %s\n", spanFile, err.Error())
+		return EXIT_FAILURE
+	}
+	defer file.Close()
+	return doLoadSpans(hcl, bufio.NewReader(file))
+}
+
+func doLoadSpanJson(hcl *htrace.Client, spanJson string) int {
+	return doLoadSpans(hcl, bytes.NewBufferString(spanJson))
+}
+
+func doLoadSpans(hcl *htrace.Client, reader io.Reader) int {
+	dec := json.NewDecoder(reader)
+	spans := make([]*common.Span, 0, 32)
+	var err error
+	for {
+		var span common.Span
+		if err = dec.Decode(&span); err != nil {
+			if err == io.EOF {
+				break
+			}
+			fmt.Printf("Failed to decode JSON: %s\n", err.Error())
+			return EXIT_FAILURE
+		}
+		spans = append(spans, &span)
+	}
+	if *verbose {
+		fmt.Printf("Writing ")
+		prefix := ""
+		for i := range spans {
+			fmt.Printf("%s%s", prefix, spans[i].ToJson())
+			prefix = ", "
+		}
+		fmt.Printf("\n")
+	}
+	err = hcl.WriteSpans(&common.WriteSpansReq{
+		Spans: spans,
+	})
+	if err != nil {
+		fmt.Println(err.Error())
+		return EXIT_FAILURE
+	}
+	return EXIT_SUCCESS
+}
+
+// Find information about the children of a span.
+func doFindChildren(hcl *htrace.Client, sid common.SpanId, lim int) int {
+	spanIds, err := hcl.FindChildren(sid, lim)
+	if err != nil {
+		fmt.Printf("%s\n", err.Error())
+		return EXIT_FAILURE
+	}
+	pbuf, err := json.MarshalIndent(spanIds, "", "  ")
+	if err != nil {
+		fmt.Println("Error: error pretty-printing span IDs to JSON: %s", err.Error())
+		return 1
+	}
+	fmt.Printf("%s\n", string(pbuf))
+	return 0
+}
+
+// Dump all spans from the htraced daemon.
+func doDumpAll(hcl *htrace.Client, outPath string, lim int) error {
+	file, err := CreateOutputFile(outPath)
+	if err != nil {
+		return err
+	}
+	w := bufio.NewWriter(file)
+	defer func() {
+		if file != nil {
+			w.Flush()
+			file.Close()
+		}
+	}()
+	out := make(chan *common.Span, 50)
+	var dumpErr error
+	go func() {
+		dumpErr = hcl.DumpAll(lim, out)
+	}()
+	var numSpans int64
+	nextLogTime := time.Now().Add(time.Second * 5)
+	for {
+		span, channelOpen := <-out
+		if !channelOpen {
+			break
+		}
+		if err == nil {
+			_, err = fmt.Fprintf(w, "%s\n", span.ToJson())
+		}
+		if *verbose {
+			numSpans++
+			now := time.Now()
+			if !now.Before(nextLogTime) {
+				nextLogTime = now.Add(time.Second * 5)
+				fmt.Printf("received %d span(s)...\n", numSpans)
+			}
+		}
+	}
+	if err != nil {
+		return errors.New(fmt.Sprintf("Write error %s", err.Error()))
+	}
+	if dumpErr != nil {
+		return errors.New(fmt.Sprintf("Dump error %s", dumpErr.Error()))
+	}
+	err = w.Flush()
+	if err != nil {
+		return err
+	}
+	err = file.Close()
+	file = nil
+	if err != nil {
+		return err
+	}
+	return nil
+}