[GitHub] [trafficcontrol] rob05c commented on a change in pull request #4993: Adds support for CSV parsing in astats

[GitBox <gi...@apache.org>]

rob05c commented on a change in pull request #4993:
URL: https://github.com/apache/trafficcontrol/pull/4993#discussion_r480198408



##########
File path: traffic_monitor/cache/astats_csv.go
##########
@@ -0,0 +1,114 @@
+package cache
+
+/*
+ * 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.
+ */
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/apache/trafficcontrol/lib/go-log"
+)
+
+type astatsDataCsv struct {
+	Ats map[string]interface{}
+}
+
+func astatsCsvParseCsv(cacheName string, data io.Reader, pollCTX interface{}) (Statistics, map[string]interface{}, error) {
+	var stats Statistics
+	var err error
+	if data == nil {
+		log.Warnf("Cannot read stats data for cache '%s' - nil data reader", cacheName)
+		return stats, nil, errors.New("handler got nil reader")
+	}
+
+	var atsData astatsDataCsv
+	atsData.Ats = make(map[string]interface{})
+	scanner := bufio.NewScanner(data)
+
+	for scanner.Scan() {
+
+		line := scanner.Text()
+		delim := strings.IndexByte(line, ',')
+
+		// No delimiter found, skip this line as invalid
+		if delim < 0 {
+			continue
+		}
+		// Special cases where we just want the string value
+		if strings.Contains(line[0:delim], "proc.") || strings.Contains(line[0:delim], "inf.name") {
+			atsData.Ats[line[0:delim]] = line[delim+1 : len(line)]
+		} else {
+			value, err := strconv.ParseFloat(line[delim+1:len(line)], 64)
+
+			// Skip values that dont parse
+			if err != nil {
+				continue
+			}
+			atsData.Ats[line[0:delim]] = value
+		}
+	}
+
+	if len(atsData.Ats) < 1 {
+		return stats, nil, errors.New("No 'global' data object found in stats_over_http payload")
+	}
+
+	statMap := atsData.Ats
+
+	// Handle system specific values and remove them from the map for precomputing to not have issues
+	if stats.Loadavg, err = LoadavgFromRawLine(statMap["proc.loadavg"].(string)); err != nil {
+		return stats, nil, fmt.Errorf("Error parsing loadavg for cache '%s': %v", cacheName, err)

Review comment:
       To add some context as to why: it's so they compose well. For example, if the parent function did
   `return errors.New("doing foo: " + err.Error())`, it ends up as a pretty sentence, "doing foo: parsing loadavg...", and the final `log.Errorln` can/should start with a capital (and could add a period at the end, though people don't usually bother with that).
   
   As a nitpick to the nitpick, the word "Error" here is superfluous for the same reason.




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