distro: Add opt-in logs support

CHANGELOG.md

@@ -8,6 +8,21 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+This release adds experimental logs support. Set `OTEL_LOGS_EXPORTER=otlp` to
+enable logs support. However, take notice that, as of now, the OpenTelemetry Go
+Logs API is not stable.
+
+### Added
+
+- Add logs support and `OTEL_LOGS_EXPORTER` environment variable.
+  `OTEL_LOGS_EXPORTER` accepts:
+  - `none` - logs disabled,
+  - `otlp` - OTLP gRPC exporter.
+
+  Currently, `OTEL_LOGS_EXPORTER` defaults to `none` as the OpenTelemetry Go
+  Logs API and SDK are not stable yet. Set `OTEL_LOGS_EXPORTER=otlp` to enable
+  logs support. (#3673)
+
 ## [1.24.0] - 2025-01-22
 
 This release upgrades [OpenTelemetry Go to v1.34.0/v0.56.0/v0.10.0][otel-v1.34.0]

distro/config.go

@@ -35,12 +35,14 @@ const (
 	// OpenTelemetry exporter to use.
 	otelTracesExporterKey  = "OTEL_TRACES_EXPORTER"
 	otelMetricsExporterKey = "OTEL_METRICS_EXPORTER"
+	otelLogsExporterKey    = "OTEL_LOGS_EXPORTER"
 
 	// OpenTelemetry exporter endpoints.
 	otelExporterJaegerEndpointKey      = "OTEL_EXPORTER_JAEGER_ENDPOINT"
 	otelExporterOTLPEndpointKey        = "OTEL_EXPORTER_OTLP_ENDPOINT"
 	otelExporterOTLPTracesEndpointKey  = "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"
 	otelExporterOTLPMetricsEndpointKey = "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT"
+	otelExporterOTLPLogsEndpointKey    = "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT"
 
 	// Logging level to set when using the default logger.
 	otelLogLevelKey = "OTEL_LOG_LEVEL"
@@ -54,6 +56,7 @@ const (
 	defaultAccessToken     = ""
 	defaultTraceExporter   = "otlp"
 	defaultMetricsExporter = "otlp"
+	defaultLogsExporter    = "none"
 	defaultLogLevel        = "info"
 
 	jaegerDefaultEndpoint     = "http://127.0.0.1:9080/v1/trace"
@@ -80,6 +83,7 @@ type config struct {
 	ExportConfig        *exporterConfig
 	TracesExporterFunc  traceExporterFunc
 	MetricsExporterFunc metricsExporterFunc
+	LogsExporterFunc    logsExporterFunc
 }
 
 // newConfig returns a validated config with Splunk defaults.
@@ -97,6 +101,7 @@ func newConfig(opts ...Option) *config {
 	}
 	c.TracesExporterFunc = tracesExporter(c.Logger)
 	c.MetricsExporterFunc = metricsExporter(c.Logger)
+	c.LogsExporterFunc = logsExporter(c.Logger)
 	return c
 }
 

distro/exporter.go

@@ -22,10 +22,12 @@ import (
 
 	"github.com/go-logr/logr"
 	"go.opentelemetry.io/otel/exporters/jaeger" //nolint:staticcheck // Jaeger is deprecated, but we still support it to not break existing users.
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	"go.opentelemetry.io/otel/sdk/log"
 	"go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/trace"
 	"google.golang.org/grpc/credentials"
@@ -236,6 +238,52 @@ func newOTLPMetricsExporter(c *exporterConfig) (metric.Exporter, error) {
 	return otlpmetricgrpc.New(ctx, opts...)
 }
 
+type logsExporterFunc func(*exporterConfig) (log.Exporter, error)
+
+// logsExporters maps environment variable values to logs exporter creation
+// functions.
+var logsExporters = map[string]logsExporterFunc{
+	// OTLP gRPC exporter.
+	"otlp": newOTLPlogExporter,
+	// None, explicitly do not set an exporter.
+	"none": nil,
+}
+
+func logsExporter(log logr.Logger) logsExporterFunc {
+	key := envOr(otelLogsExporterKey, defaultLogsExporter)
+	lef, ok := logsExporters[key]
+	if !ok {
+		err := fmt.Errorf("invalid %s: %q", otelLogsExporterKey, key)
+		log.Error(err, "using default %s: %q", otelLogsExporterKey, defaultLogsExporter)
+
+		return logsExporters[defaultLogsExporter]
+	}
+	return lef
+}
+
+func newOTLPlogExporter(c *exporterConfig) (log.Exporter, error) {
+	ctx := context.Background()
+
+	var opts []otlploggrpc.Option
+
+	// SPLUNK_REALM is not supported, Splunk Observability ingest does not support OTLP.
+	if c.AccessToken != "" {
+		opts = append(opts, otlploggrpc.WithHeaders(map[string]string{
+			"X-Sf-Token": c.AccessToken,
+		}))
+	}
+
+	if c.TLSConfig != nil {
+		tlsCreds := credentials.NewTLS(c.TLSConfig)
+		opts = append(opts, otlploggrpc.WithTLSCredentials(tlsCreds))
+	} else if noneEnvVarSet(otelExporterOTLPEndpointKey, otelExporterOTLPLogsEndpointKey) {
+		// Assume that the default endpoint (local collector) is non-TLS.
+		opts = append(opts, otlploggrpc.WithTLSCredentials(insecure.NewCredentials()))
+	}
+
+	return otlploggrpc.New(ctx, opts...)
+}
+
 // noneEnvVarSet returns true if none of provided env vars is set.
 func noneEnvVarSet(envs ...string) bool {
 	for _, env := range envs {

distro/go.mod

@@ -11,11 +11,14 @@ require (
 	go.opentelemetry.io/contrib/propagators/autoprop v0.59.0
 	go.opentelemetry.io/otel v1.34.0
 	go.opentelemetry.io/otel/exporters/jaeger v1.17.0
+	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.8.0
 	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.34.0
 	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.34.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.34.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.34.0
+	go.opentelemetry.io/otel/log v0.8.0
 	go.opentelemetry.io/otel/sdk v1.34.0
+	go.opentelemetry.io/otel/sdk/log v0.8.0
 	go.opentelemetry.io/otel/sdk/metric v1.34.0
 	go.opentelemetry.io/otel/trace v1.34.0
 	go.opentelemetry.io/proto/otlp v1.5.0

distro/go.sum

@@ -49,6 +49,8 @@ go.opentelemetry.io/otel v1.34.0 h1:zRLXxLCgL1WyKsPVrgbSdMN4c0FMkDAskSTQP+0hdUY=
 go.opentelemetry.io/otel v1.34.0/go.mod h1:OWFPOQ+h4G8xpyjgqo4SxJYdDQ/qmRH+wivy7zzx9oI=
 go.opentelemetry.io/otel/exporters/jaeger v1.17.0 h1:D7UpUy2Xc2wsi1Ras6V40q806WM07rqoCWzXu7Sqy+4=
 go.opentelemetry.io/otel/exporters/jaeger v1.17.0/go.mod h1:nPCqOnEH9rNLKqH/+rrUjiMzHJdV1BlpKcTwRTyKkKI=
+go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.8.0 h1:WzNab7hOOLzdDF/EoWCt4glhrbMPVMOO5JYTmpz36Ls=
+go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.8.0/go.mod h1:hKvJwTzJdp90Vh7p6q/9PAOd55dI6WA6sWj62a/JvSs=
 go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.34.0 h1:ajl4QczuJVA2TU9W9AGw++86Xga/RKt//16z/yxPgdk=
 go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.34.0/go.mod h1:Vn3/rlOJ3ntf/Q3zAI0V5lDnTbHGaUsNUeF6nZmm7pA=
 go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.34.0 h1:opwv08VbCZ8iecIWs+McMdHRcAXzjAeda3uG2kI/hcA=
@@ -59,10 +61,14 @@ go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.34.0 h1:tgJ0u
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.34.0/go.mod h1:U7HYyW0zt/a9x5J1Kjs+r1f/d4ZHnYFclhYY2+YbeoE=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.34.0 h1:BEj3SPM81McUZHYjRS5pEgNgnmzGJ5tRpU5krWnV8Bs=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.34.0/go.mod h1:9cKLGBDzI/F3NoHLQGm4ZrYdIHsvGt6ej6hUowxY0J4=
+go.opentelemetry.io/otel/log v0.8.0 h1:egZ8vV5atrUWUbnSsHn6vB8R21G2wrKqNiDt3iWertk=
+go.opentelemetry.io/otel/log v0.8.0/go.mod h1:M9qvDdUTRCopJcGRKg57+JSQ9LgLBrwwfC32epk5NX8=
 go.opentelemetry.io/otel/metric v1.34.0 h1:+eTR3U0MyfWjRDhmFMxe2SsW64QrZ84AOhvqS7Y+PoQ=
 go.opentelemetry.io/otel/metric v1.34.0/go.mod h1:CEDrp0fy2D0MvkXE+dPV7cMi8tWZwX3dmaIhwPOaqHE=
 go.opentelemetry.io/otel/sdk v1.34.0 h1:95zS4k/2GOy069d321O8jWgYsW3MzVV+KuSPKp7Wr1A=
 go.opentelemetry.io/otel/sdk v1.34.0/go.mod h1:0e/pNiaMAqaykJGKbi+tSjWfNNHMTxoC9qANsCzbyxU=
+go.opentelemetry.io/otel/sdk/log v0.8.0 h1:zg7GUYXqxk1jnGF/dTdLPrK06xJdrXgqgFLnI4Crxvs=
+go.opentelemetry.io/otel/sdk/log v0.8.0/go.mod h1:50iXr0UVwQrYS45KbruFrEt4LvAdCaWWgIrsN3ZQggo=
 go.opentelemetry.io/otel/sdk/metric v1.34.0 h1:5CeK9ujjbFVL5c1PhLuStg1wxA7vQv7ce1EK0Gyvahk=
 go.opentelemetry.io/otel/sdk/metric v1.34.0/go.mod h1:jQ/r8Ze28zRKoNRdkjCZxfs6YvBTG1+YIqyFVFYec5w=
 go.opentelemetry.io/otel/trace v1.34.0 h1:+ouXS2V8Rd4hp4580a8q23bg0azF2nI8cqLYnC8mh/k=

distro/otel.go

@@ -23,6 +23,8 @@ import (
 	"go.opentelemetry.io/contrib/instrumentation/runtime"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/log/global"
+	"go.opentelemetry.io/otel/sdk/log"
 	"go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/resource"
 	"go.opentelemetry.io/otel/sdk/trace"
@@ -104,6 +106,15 @@ func Run(opts ...Option) (SDK, error) {
 		sdk.shutdownFuncs = append(sdk.shutdownFuncs, shutdownFn)
 	}
 
+	shutdownFn, err = runLogs(c, res)
+	if err != nil {
+		sdk.Shutdown(ctx) //nolint:errcheck // the Shutdown errors are logged
+		return SDK{}, err
+	}
+	if shutdownFn != nil {
+		sdk.shutdownFuncs = append(sdk.shutdownFuncs, shutdownFn)
+	}
+
 	return sdk, nil
 }
 
@@ -189,6 +200,29 @@ func runMetrics(c *config, res *resource.Resource) (shutdownFunc, error) {
 	return provider.Shutdown, nil
 }
 
+func runLogs(c *config, res *resource.Resource) (shutdownFunc, error) {
+	if c.LogsExporterFunc == nil {
+		c.Logger.V(1).Info("OTEL_LOGS_EXPORTER set to none: Logs disabled")
+		// "none" exporter configured.
+		return nil, nil
+	}
+
+	exp, err := c.LogsExporterFunc(c.ExportConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	o := []log.LoggerProviderOption{
+		log.WithResource(res),
+		log.WithProcessor(log.NewBatchProcessor(exp)),
+	}
+
+	provider := log.NewLoggerProvider(o...)
+	global.SetLoggerProvider(provider)
+
+	return provider.Shutdown, nil
+}
+
 func serviceNameDefined(r *resource.Resource) bool {
 	val, ok := r.Set().Value("service.name")
 	return ok && val.Type() == attribute.STRING && !strings.HasPrefix(val.AsString(), "unknown_service:")