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Posted to commits@trafficserver.apache.org by su...@apache.org on 2016/02/29 19:11:23 UTC
trafficserver git commit: [TS-4243] Collapsed Forwarding Plugin based
on Open Write Fail Action feature.
Repository: trafficserver
Updated Branches:
refs/heads/fcollapse [created] d2bdb0bb0
[TS-4243] Collapsed Forwarding Plugin based on Open Write Fail Action feature.
Project: http://git-wip-us.apache.org/repos/asf/trafficserver/repo
Commit: http://git-wip-us.apache.org/repos/asf/trafficserver/commit/d2bdb0bb
Tree: http://git-wip-us.apache.org/repos/asf/trafficserver/tree/d2bdb0bb
Diff: http://git-wip-us.apache.org/repos/asf/trafficserver/diff/d2bdb0bb
Branch: refs/heads/fcollapse
Commit: d2bdb0bb03a0835a29b5d1ef3c424238c9cfc73c
Parents: 5731dbb
Author: Sudheer Vinukonda <su...@yahoo-inc.com>
Authored: Mon Feb 29 18:09:42 2016 +0000
Committer: Sudheer Vinukonda <su...@yahoo-inc.com>
Committed: Mon Feb 29 18:09:42 2016 +0000
----------------------------------------------------------------------
configure.ac | 1 +
.../collapsed_forwarding/Makefile.am | 21 ++
.../experimental/collapsed_forwarding/README | 46 +++
.../collapsed_forwarding.cc | 318 +++++++++++++++++++
4 files changed, 386 insertions(+)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/trafficserver/blob/d2bdb0bb/configure.ac
----------------------------------------------------------------------
diff --git a/configure.ac b/configure.ac
index b9981a6..530d8c7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1942,6 +1942,7 @@ AC_CONFIG_FILES([
plugins/experimental/generator/Makefile
plugins/experimental/geoip_acl/Makefile
plugins/experimental/header_normalize/Makefile
+ plugins/experimental/collapsed_forwarding/Makefile
plugins/experimental/hipes/Makefile
plugins/experimental/inliner/Makefile
plugins/experimental/memcache/Makefile
http://git-wip-us.apache.org/repos/asf/trafficserver/blob/d2bdb0bb/plugins/experimental/collapsed_forwarding/Makefile.am
----------------------------------------------------------------------
diff --git a/plugins/experimental/collapsed_forwarding/Makefile.am b/plugins/experimental/collapsed_forwarding/Makefile.am
new file mode 100644
index 0000000..6e46a92
--- /dev/null
+++ b/plugins/experimental/collapsed_forwarding/Makefile.am
@@ -0,0 +1,21 @@
+# 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.
+
+include $(top_srcdir)/build/plugins.mk
+
+pkglib_LTLIBRARIES = collapsed_forwarding.la
+collapsed_forwarding_la_SOURCES = collapsed_forwarding.cc
+collapsed_forwarding_la_LDFLAGS = $(TS_PLUGIN_LDFLAGS)
http://git-wip-us.apache.org/repos/asf/trafficserver/blob/d2bdb0bb/plugins/experimental/collapsed_forwarding/README
----------------------------------------------------------------------
diff --git a/plugins/experimental/collapsed_forwarding/README b/plugins/experimental/collapsed_forwarding/README
new file mode 100644
index 0000000..72fe545
--- /dev/null
+++ b/plugins/experimental/collapsed_forwarding/README
@@ -0,0 +1,46 @@
+////////////////////////////////////////////////////////////////////////////////
+// collapsed_forwarding::
+//
+// ATS plugin to allow collapsed forwarding of concurrent requests for the same
+// object. This plugin is based on open_write_fail_action feature, which detects
+// cache open write failure on a cache miss and returns a 502 error along with a
+// special @-header indicating the reason for 502 error. The plugin acts on the
+// error by using an internal redirect follow back to itself, essentially blocking
+// the request until a response arrives, at which point, relies on read-while-writer
+// feature to start downloading the object to all waiting clients. The following
+// config parameters are assumed to be set for this plugin to work:
+////////////////////////////////////////////////////////////////////////////////////
+// proxy.config.http.cache.open_write_fail_action 1 /////////////////////////
+// proxy.config.cache.enable_read_while_writer 1 /////////////////////////
+// proxy.config.http.redirection_enabled 1 /////////////////////////
+// proxy.config.http.number_of_redirections 10 /////////////////////////
+// proxy.config.http.redirect_use_orig_cache_key 1 /////////////////////////
+// proxy.config.http.background_fill_active_timeout 0 /////////////////////////
+// proxy.config.http.background_fill_completed_threshold 0 /////////////////////////
+////////////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////
+// This plugin currently supports only per-remap mode activation.
+////////////////////////////////////////////////////////////////////////////////////
+
+More details are available at
+
+https://docs.trafficserver.apache.org/en/6.0.x/admin/http-proxy-caching.en.html#reducing-origin-server-requests-avoiding-the-thundering-herd
+
+Installation:
+
+ make
+ sudo make install
+
+If you don't have the traffic server binaries in your path, then you will need
+to specify the path to tsxs manually:
+
+ make TSXS=/opt/trafficserver/bin/tsxs
+ sudo make TSXS=/opt/trafficserver/bin/tsxs install
+
+Configuration:
+
+ Add @plugin=cache_range_requests.so to your remap.config rules.
+
+ Or for a global plugin where all range requests are processed,
+ Add cache_range_requests.so to the plugin.config
+
http://git-wip-us.apache.org/repos/asf/trafficserver/blob/d2bdb0bb/plugins/experimental/collapsed_forwarding/collapsed_forwarding.cc
----------------------------------------------------------------------
diff --git a/plugins/experimental/collapsed_forwarding/collapsed_forwarding.cc b/plugins/experimental/collapsed_forwarding/collapsed_forwarding.cc
new file mode 100644
index 0000000..5606d6b
--- /dev/null
+++ b/plugins/experimental/collapsed_forwarding/collapsed_forwarding.cc
@@ -0,0 +1,318 @@
+/** @file
+
+ Plugin to perform background fetches of certain content that would
+ otherwise not be cached. For example, Range: requests / responses.
+
+ @section license License
+
+ 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.
+*/
+
+////////////////////////////////////////////////////////////////////////////////
+// collapsed_forwarding::
+//
+// ATS plugin to allow collapsed forwarding of concurrent requests for the same
+// object. This plugin is based on open_write_fail_action feature, which detects
+// cache open write failure on a cache miss and returns a 502 error along with a
+// special @-header indicating the reason for 502 error. The plugin acts on the
+// error by using an internal redirect follow back to itself, essentially blocking
+// the request until a response arrives, at which point, relies on read-while-writer
+// feature to start downloading the object to all waiting clients. The following
+// config parameters are assumed to be set for this plugin to work:
+////////////////////////////////////////////////////////////////////////////////////
+// proxy.config.http.cache.open_write_fail_action 1 /////////////////////////
+// proxy.config.cache.enable_read_while_writer 1 /////////////////////////
+// proxy.config.http.redirection_enabled 1 /////////////////////////
+// proxy.config.http.number_of_redirections 10 /////////////////////////
+// proxy.config.http.redirect_use_orig_cache_key 1 /////////////////////////
+// proxy.config.http.background_fill_active_timeout 0 /////////////////////////
+// proxy.config.http.background_fill_completed_threshold 0 /////////////////////////
+////////////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////
+// This plugin currently supports only per-remap mode activation.
+////////////////////////////////////////////////////////////////////////////////////
+
+#define UNUSED __attribute__((unused))
+static char UNUSED rcsId__header_normalize_cc[] =
+ "@(#) $Id: collapsed_forwarding.cc 218 2016-02-26 01:29:16Z sudheerv $ built on " __DATE__ " " __TIME__;
+
+
+#include <sys/time.h>
+#include <ts/ts.h>
+#include <ts/remap.h>
+#include <set>
+#include <string>
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <getopt.h>
+#include <netdb.h>
+#include <map>
+
+const char *DEBUG_TAG = (char*)"collapsed_forwarding";
+
+const char *LOCATION_HEADER = "Location";
+const char *REDIRECT_REASON = "See Other";
+const char *ATS_INTERNAL_MESSAGE = "@Ats-Internal";
+
+int OPEN_WRITE_FAIL_MAX_REQ_DELAY_RETRIES = 5;
+int OPEN_WRITE_FAIL_REQ_DELAY_TIMEOUT = 500;
+
+typedef struct _RequestData {
+ TSHttpTxn txnp;
+ int wl_retry; // write lock failure retry count
+ std::string req_url;
+} RequestData;
+
+int
+add_redirect_header(TSMBuffer& bufp, TSMLoc& hdr_loc, const std::string& location)
+{
+ // This is needed in case the response already contains a Location header
+ TSMLoc field_loc = TSMimeHdrFieldFind(bufp, hdr_loc, LOCATION_HEADER, strlen(LOCATION_HEADER));
+
+ if (field_loc == TS_NULL_MLOC) {
+ TSMimeHdrFieldCreateNamed(bufp, hdr_loc, LOCATION_HEADER, strlen(LOCATION_HEADER), &field_loc);
+ }
+
+ if (TS_SUCCESS == TSMimeHdrFieldValueStringSet(bufp, hdr_loc, field_loc, -1, location.c_str(), location.size())) {
+ TSDebug(DEBUG_TAG, "Adding Location header %s", LOCATION_HEADER);
+ TSMimeHdrFieldAppend(bufp, hdr_loc, field_loc);
+ }
+
+ TSHandleMLocRelease(bufp, hdr_loc, field_loc);
+
+ TSHttpHdrStatusSet(bufp, hdr_loc, TS_HTTP_STATUS_SEE_OTHER);
+ TSHttpHdrReasonSet(bufp, hdr_loc, REDIRECT_REASON, strlen(REDIRECT_REASON));
+ return TS_SUCCESS;
+}
+
+bool
+check_internal_message_hdr(TSHttpTxn& txnp)
+{
+ TSMBuffer bufp;
+ TSMLoc hdr_loc;
+ bool found = false;
+
+ if (TSHttpTxnClientRespGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
+ TSError("check_internal_message_hdr: couldn't retrieve client response header");
+ return false;
+ }
+
+ TSMLoc header_loc = TSMimeHdrFieldFind(bufp, hdr_loc, ATS_INTERNAL_MESSAGE, strlen(ATS_INTERNAL_MESSAGE));
+ if (header_loc) {
+ found = true;
+ // found the header, remove it now..
+ TSMimeHdrFieldDestroy(bufp, hdr_loc, header_loc);
+ TSHandleMLocRelease(bufp, hdr_loc, header_loc);
+ }
+
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+
+ return found;
+}
+
+int
+on_OS_DNS(const RequestData* req, TSHttpTxn& txnp)
+{
+ if (req->wl_retry > 0) {
+ TSDebug (DEBUG_TAG, "OS_DNS request delayed %d times, block origin req for url: %s", req->wl_retry, req->req_url.c_str());
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_ERROR);
+ return TS_SUCCESS;
+ }
+
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+int
+on_send_request_header(const RequestData* req, TSHttpTxn& txnp)
+{
+ if (req->wl_retry > 0) {
+ TSDebug (DEBUG_TAG, "Send_Req request delayed %d times, block origin req for url: %s", req->wl_retry, req->req_url.c_str());
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_ERROR);
+ return TS_SUCCESS;
+ }
+
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+int
+on_read_response_header(TSHttpTxn& txnp)
+{
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+int
+on_immediate(RequestData* req, TSCont& contp)
+{
+ if (!req) {
+ TSError ("%s: invalid req_data", DEBUG_TAG);
+ return TS_SUCCESS;
+ }
+
+ TSDebug (DEBUG_TAG, "continuation delayed, scheduling now..for url: %s", req->req_url.c_str());
+
+ // add retry_done header to prevent looping
+ std::string value;
+ TSMBuffer bufp;
+ TSMLoc hdr_loc;
+ if (TSHttpTxnClientRespGet(req->txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
+ TSError("plugin=%s, level=error, error_code=could_not_retrieve_client_response_header for url %s", DEBUG_TAG, req->req_url.c_str());
+ TSHttpTxnReenable(req->txnp, TS_EVENT_HTTP_ERROR);
+ return TS_SUCCESS;
+ }
+
+ add_redirect_header(bufp, hdr_loc, req->req_url);
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ TSHttpTxnReenable(req->txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+int
+on_send_response_header(RequestData* req, TSHttpTxn& txnp, TSCont& contp)
+{
+ TSMBuffer bufp;
+ TSMLoc hdr_loc;
+ if (TSHttpTxnClientRespGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
+ TSError("plugin=%s, level=error, error_code=could_not_retrieve_client_response_header", DEBUG_TAG);
+ return TS_SUCCESS;
+ }
+
+ TSHttpStatus status = TSHttpHdrStatusGet(bufp, hdr_loc);
+ TSDebug(DEBUG_TAG, "Response code: %d", status);
+
+ if ((status == TS_HTTP_STATUS_BAD_GATEWAY) || (status == TS_HTTP_STATUS_SEE_OTHER)) {
+ bool is_internal_message_hdr = check_internal_message_hdr(txnp);
+ bool delay_request = is_internal_message_hdr ||
+ ((req->wl_retry > 0) && (req->wl_retry < OPEN_WRITE_FAIL_MAX_REQ_DELAY_RETRIES));
+
+ if (delay_request) {
+ req->wl_retry++;
+ TSDebug (DEBUG_TAG, "delaying request, url@%p: {{%s}} on retry: %d time", txnp, req->req_url.c_str(), req->wl_retry);
+ TSContSchedule(contp, OPEN_WRITE_FAIL_REQ_DELAY_TIMEOUT, TS_THREAD_POOL_TASK);
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return TS_SUCCESS;
+ }
+ }
+
+ if (req->wl_retry > 0) {
+ TSDebug (DEBUG_TAG, "request delayed, but unsuccessful, url@%p: {{%s}} on retry: %d time", txnp, req->req_url.c_str(), req->wl_retry);
+ req->wl_retry = 0;
+ }
+
+ // done..cleanup
+ TSfree(req);
+ TSContDestroy(contp);
+
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+int
+collapsed_cont(TSCont contp, TSEvent event, void *edata)
+{
+ TSHttpTxn txnp = static_cast<TSHttpTxn>(edata);
+ RequestData *my_req = static_cast<RequestData*>(TSContDataGet(contp));
+
+ switch (event) {
+ case TS_EVENT_HTTP_OS_DNS:
+ {
+ return on_OS_DNS(my_req, txnp);
+ }
+
+ case TS_EVENT_HTTP_SEND_REQUEST_HDR:
+ {
+ return on_send_request_header(my_req, txnp);
+ }
+
+ case TS_EVENT_HTTP_READ_RESPONSE_HDR:
+ {
+ return on_read_response_header(txnp);
+ }
+ case TSEvent::TS_EVENT_IMMEDIATE:
+ case TSEvent::TS_EVENT_TIMEOUT:
+ {
+ return on_immediate(my_req, contp);
+ }
+ case TS_EVENT_HTTP_SEND_RESPONSE_HDR:
+ {
+ return on_send_response_header(my_req, txnp, contp);
+ }
+ default:
+ {
+ TSDebug(DEBUG_TAG, "Unexpected event: %d", event);
+ break;
+ }
+ }
+
+ TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+ return TS_SUCCESS;
+}
+
+TSReturnCode
+TSRemapInit(TSRemapInterface * /* api_info */, char * /* errbuf */, int /* errbuf_size */)
+{
+ TSDebug(DEBUG_TAG, "plugin is succesfully initialized");
+ return TS_SUCCESS;
+}
+
+TSReturnCode
+TSRemapNewInstance(int argc, char * argv[], void ** /* ih */, char * /* errbuf */, int /* errbuf_size */)
+{
+ // basic argv processing..
+ for (int i = 2; i < argc; ++i) {
+ if (strncmp(argv[i], "--delay=", 8) == 0) {
+ OPEN_WRITE_FAIL_REQ_DELAY_TIMEOUT = atoi((char *)(argv[i] + 8));
+ } else if (strncmp(argv[i], "--retries=", 10) == 0) {
+ OPEN_WRITE_FAIL_MAX_REQ_DELAY_RETRIES = atoi((char *)(argv[i] + 10));
+ }
+ }
+
+ return TS_SUCCESS;
+}
+
+TSRemapStatus
+TSRemapDoRemap(void* ih, TSHttpTxn rh, TSRemapRequestInfo *rri)
+{
+ TSCont cont = TSContCreate(collapsed_cont, TSMutexCreate());
+
+ RequestData *req_data;
+ req_data = static_cast<RequestData *>(TSmalloc(sizeof(RequestData)));
+ memset(req_data, 0, sizeof(RequestData));
+
+ req_data->txnp = rh;
+ req_data->wl_retry = 0;
+
+ int url_len = 0;
+ char *url = TSHttpTxnEffectiveUrlStringGet(rh, &url_len);
+ req_data->req_url = std::string(url, url_len);
+
+ TSfree(url);
+ TSContDataSet(cont, req_data);
+
+ TSHttpTxnHookAdd(rh, TS_HTTP_SEND_REQUEST_HDR_HOOK, cont);
+ TSHttpTxnHookAdd(rh, TS_HTTP_SEND_RESPONSE_HDR_HOOK, cont);
+ TSHttpTxnHookAdd(rh, TS_HTTP_READ_RESPONSE_HDR_HOOK, cont);
+ TSHttpTxnHookAdd(rh, TS_HTTP_OS_DNS_HOOK, cont);
+
+ return TSREMAP_DID_REMAP;
+}