feat(logcli): output modes

Adds two alternative output modes (-o / --output)

- raw: emits the line as parsed
- jsonl: emits the line plus all known metadata as JSONL (JSON Line)

Usage: -o [default, raw, jsonl]

cmd/logcli/main.go

@@ -8,8 +8,9 @@ import (
 )
 
 var (
-	app = kingpin.New("logcli", "A command-line for loki.")
+	app        = kingpin.New("logcli", "A command-line for loki.")
 	quiet      = app.Flag("quiet", "suppress everything but log lines").Default("false").Short('q').Bool()
+	outputMode = app.Flag("output", "specify output mode [default, raw, jsonl]").Default("default").Short('o').Enum("default", "raw", "jsonl")
 
 	addr     = app.Flag("addr", "Server address.").Default("https://logs-us-west1.grafana.net").Envar("GRAFANA_ADDR").String()
 	username = app.Flag("username", "Username for HTTP basic auth.").Default("").Envar("GRAFANA_USERNAME").String()

cmd/logcli/query.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"strings"
 	"time"
@@ -72,8 +73,8 @@ func doQuery() {
 	i = iter.NewQueryResponseIterator(resp, d)
 
 	for i.Next() {
-		ls := labelsCache(i.Labels())
-		ls = subtract(ls, common)
+		fullls := labelsCache(i.Labels())
+		ls := subtract(fullls, common)
 		if len(*ignoreLabelsKey) > 0 {
 			ls = ls.MatchLabels(false, *ignoreLabelsKey...)
 		}
@@ -83,7 +84,14 @@ func doQuery() {
 			labels = padLabel(ls, maxLabelsLen)
 		}
 
-		printLogEntry(i.Entry().Timestamp, labels, i.Entry().Line)
+		switch *outputMode {
+		case "jsonl":
+			printLogEntryJSONL(i.Entry().Timestamp, fullls, i.Entry().Line)
+		case "raw":
+			fmt.Println(i.Entry().Line)
+		default:
+			printLogEntry(i.Entry().Timestamp, labels, i.Entry().Line)
+		}
 	}
 
 	if err := i.Error(); err != nil {

cmd/logcli/utils.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
 	"sort"
@@ -22,6 +23,20 @@ func printLogEntry(ts time.Time, lbls string, line string) {
 	)
 }
 
+// print a log entry as json line
+func printLogEntryJSONL(ts time.Time, lbls labels.Labels, line string) {
+	entry := map[string]interface{}{
+		"timestamp": ts,
+		"labels":    lbls,
+		"line":      line,
+	}
+	out, err := json.Marshal(entry)
+	if err != nil {
+		log.Fatalf("error marshalling entry: %s", err)
+	}
+	fmt.Println(string(out))
+}
+
 // add some padding after labels
 func padLabel(ls labels.Labels, maxLabelsLen int) string {
 	labels := ls.String()