Merge pull request #3 from yangl900/metadata

Support sending metadata from environment variables

log2oms.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/hpcloud/tail"
@@ -14,6 +15,7 @@ const (
 	envLogType         = "LOG2OMS_LOG_TYPE"
 	envWorkspaceID     = "LOG2OMS_WORKSPACE_ID"
 	envWorkspaceSecret = "LOG2OMS_WORKSPACE_SECRET"
+	envMetadataPrefix  = "LOG2OMS_META_"
 )
 
 var (
@@ -28,6 +30,22 @@ func logLines(client *logclient.LogClient, lines []string) {
 	}
 }
 
+func metadata() map[string]string {
+	metadata := make(map[string]string)
+	metadata["Hostname"], _ = os.Hostname()
+
+	for _, e := range os.Environ() {
+		pair := strings.Split(e, "=")
+
+		if strings.HasPrefix(pair[0], envMetadataPrefix) {
+			key := strings.TrimPrefix(pair[0], envMetadataPrefix)
+			metadata[key] = pair[1]
+		}
+	}
+
+	return metadata
+}
+
 func main() {
 	workspaceID, workspaceSecret := os.Getenv(envWorkspaceID), os.Getenv(envWorkspaceSecret)
 	if workspaceID == "" || workspaceSecret == "" {
@@ -50,9 +68,14 @@ func main() {
 		logType = "container_logs"
 	}
 
+	metadata := metadata()
+	for m := range metadata {
+		fmt.Printf("[LOG2OMS][%s] %s = %s\n", time.Now().UTC().Format(time.RFC3339), m, metadata[m])
+	}
+
 	fmt.Printf("[LOG2OMS][%s] Start tail logs from: %s\n", time.Now().UTC().Format(time.RFC3339), logfile)
 
-	client := logclient.NewLogClient(workspaceID, workspaceSecret, logType)
+	client := logclient.NewLogClient(workspaceID, workspaceSecret, logType, metadata)
 
 	t, err := tail.TailFile(logfile, tail.Config{ReOpen: true, Follow: true})
 	if err != nil {

logclient/logclient.go

@@ -23,18 +23,20 @@ type LogClient struct {
 	httpClient      *http.Client
 	signingKey      []byte
 	apiLogsURL      string
-}
-
-type log struct {
-	Data string `json:"data"`
+	metadata        map[string]string
 }
 
 // NewLogClient creates a log client
-func NewLogClient(workspaceID, workspaceSecret, logType string) LogClient {
+func NewLogClient(workspaceID, workspaceSecret, logType string, metadata map[string]string) LogClient {
 	client := LogClient{
 		workspaceID:     workspaceID,
 		workspaceSecret: workspaceSecret,
 		logType:         logType,
+		metadata:        metadata,
+	}
+
+	if client.metadata == nil {
+		client.metadata = map[string]string{}
 	}
 
 	client.httpClient = &http.Client{Timeout: time.Second * 30}
@@ -51,9 +53,15 @@ func (c *LogClient) PostMessage(message string, timestamp time.Time) error {
 
 // PostMessages logs an array of messages to log analytics service
 func (c *LogClient) PostMessages(messages []string, timestamp time.Time) error {
-	var logs []log
+	var logs []map[string]string
 	for _, m := range messages {
-		logs = append(logs, log{Data: m})
+		log := make(map[string]string, len(c.metadata)+1)
+		for item := range c.metadata {
+			log[item] = c.metadata[item]
+		}
+		log["message"] = m
+
+		logs = append(logs, log)
 	}
 
 	if timestamp.IsZero() {