Add json format support for log export via faro receiver

CHANGELOG.md

@@ -49,6 +49,7 @@ Main (unreleased)
   - Add perf_schema quantile columns to collector
 
 - Live Debugging button should appear in UI only for supported components (@ravishankar15)
+- Add json format support for log export via faro receiver (@ravishankar15)
 - Add three new stdlib functions to_base64, from_URLbase64 and to_URLbase64 (@ravishankar15)
 - Add `ignore_older_than` option for local.file_match (@ravishankar15)
 - Add livedebugging support for `discover.relabel` (@ravishankar15)

docs/sources/reference/components/faro/faro.receiver.md

@@ -30,6 +30,14 @@ The following arguments are supported:
 Name               | Type          | Description                                  | Default | Required
 -------------------|---------------|----------------------------------------------|---------|---------
 `extra_log_labels` | `map(string)` | Extra labels to attach to emitted log lines. | `{}`    | no
+`log_format`       | `string`      | Export format for the logs.                  | `logfmt`| no
+
+### Log format
+
+The following strings are recognized as valid log line formats:
+
+* `"logfmt"`: Export logs as [logfmt](https://brandur.org/logfmt) lines.
+* `"json"`: Export logs as JSON objects.
 
 ## Blocks
 

internal/component/faro/receiver/arguments.go

@@ -1,6 +1,8 @@
 package receiver
 
 import (
+	"encoding"
+	"fmt"
 	"time"
 
 	"github.com/alecthomas/units"
@@ -13,6 +15,7 @@ import (
 // Arguments configures the app_agent_receiver component.
 type Arguments struct {
 	LogLabels map[string]string `alloy:"extra_log_labels,attr,optional"`
+	LogFormat LogFormat         `alloy:"log_format,attr,optional"`
 
 	Server     ServerArguments     `alloy:"server,block,optional"`
 	SourceMaps SourceMapsArguments `alloy:"sourcemaps,block,optional"`
@@ -23,6 +26,7 @@ var _ syntax.Defaulter = (*Arguments)(nil)
 
 // SetToDefault applies default settings.
 func (args *Arguments) SetToDefault() {
+	args.LogFormat = FormatDefault
 	args.Server.SetToDefault()
 	args.SourceMaps.SetToDefault()
 }
@@ -93,3 +97,33 @@ type OutputArguments struct {
 	Logs   []loki.LogsReceiver `alloy:"logs,attr,optional"`
 	Traces []otelcol.Consumer  `alloy:"traces,attr,optional"`
 }
+
+type LogFormat string
+
+const (
+	FormatLogfmt LogFormat = "logfmt"
+	FormatJSON   LogFormat = "json"
+
+	FormatDefault = FormatLogfmt
+)
+
+var (
+	_ encoding.TextMarshaler   = FormatDefault
+	_ encoding.TextUnmarshaler = (*LogFormat)(nil)
+)
+
+func (ll LogFormat) MarshalText() (text []byte, err error) {
+	return []byte(ll), nil
+}
+
+func (ll *LogFormat) UnmarshalText(text []byte) error {
+	switch LogFormat(text) {
+	case "":
+		*ll = FormatDefault
+	case FormatLogfmt, FormatJSON:
+		*ll = LogFormat(text)
+	default:
+		return fmt.Errorf("unrecognized log format %q", string(text))
+	}
+	return nil
+}

internal/component/faro/receiver/exporters.go

@@ -2,6 +2,7 @@ package receiver
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"sync"
@@ -83,6 +84,7 @@ func (exp *metricsExporter) Export(ctx context.Context, p payload.Payload) error
 type logsExporter struct {
 	log        log.Logger
 	sourceMaps sourceMapsStore
+	format     LogFormat
 
 	receiversMut sync.RWMutex
 	receivers    []loki.LogsReceiver
@@ -93,10 +95,11 @@ type logsExporter struct {
 
 var _ exporter = (*logsExporter)(nil)
 
-func newLogsExporter(log log.Logger, sourceMaps sourceMapsStore) *logsExporter {
+func newLogsExporter(log log.Logger, sourceMaps sourceMapsStore, format LogFormat) *logsExporter {
 	return &logsExporter{
 		log:        log,
 		sourceMaps: sourceMaps,
+		format:     format,
 	}
 }
 
@@ -157,7 +160,19 @@ func (exp *logsExporter) sendKeyValsToLogsPipeline(ctx context.Context, kv *payl
 	)
 	exp.receiversMut.RUnlock()
 
-	line, err := logfmt.MarshalKeyvals(payload.KeyValToInterfaceSlice(kv)...)
+	var (
+		line []byte
+		err  error
+	)
+	switch exp.format {
+	case FormatLogfmt:
+		line, err = logfmt.MarshalKeyvals(payload.KeyValToInterfaceSlice(kv)...)
+	case FormatJSON:
+		line, err = json.Marshal(payload.KeyValToInterfaceMap(kv))
+	default:
+		line, err = logfmt.MarshalKeyvals(payload.KeyValToInterfaceSlice(kv)...)
+	}
+
 	if err != nil {
 		level.Error(exp.log).Log("msg", "failed to logfmt a frontend log event", "err", err)
 		return err