slogdatadog

slog: Datadog handler

A Datadog Handler for slog Go library.

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See also:

• slog-multi: slog.Handler chaining, fanout, routing, failover, load balancing...
• slog-formatter: slog attribute formatting
• slog-sampling: slog sampling policy
• slog-mock: slog.Handler for test purposes

HTTP middlewares:

• slog-gin: Gin middleware for slog logger
• slog-echo: Echo middleware for slog logger
• slog-fiber: Fiber middleware for slog logger
• slog-chi: Chi middleware for slog logger
• slog-http: net/http middleware for slog logger

Loggers:

• slog-zap: A slog handler for Zap
• slog-zerolog: A slog handler for Zerolog
• slog-logrus: A slog handler for Logrus

Log sinks:

• slog-datadog: A slog handler for Datadog
• slog-betterstack: A slog handler for Betterstack
• slog-rollbar: A slog handler for Rollbar
• slog-loki: A slog handler for Loki
• slog-sentry: A slog handler for Sentry
• slog-syslog: A slog handler for Syslog
• slog-logstash: A slog handler for Logstash
• slog-fluentd: A slog handler for Fluentd
• slog-graylog: A slog handler for Graylog
• slog-quickwit: A slog handler for Quickwit
• slog-slack: A slog handler for Slack
• slog-telegram: A slog handler for Telegram
• slog-mattermost: A slog handler for Mattermost
• slog-microsoft-teams: A slog handler for Microsoft Teams
• slog-webhook: A slog handler for Webhook
• slog-kafka: A slog handler for Kafka
• slog-nats: A slog handler for NATS
• slog-parquet: A slog handler for Parquet + Object Storage
• slog-channel: A slog handler for Go channels

🚀 Install

go get github.com/samber/slog-datadog/v2

Compatibility: go >= 1.21

No breaking changes will be made to exported APIs before v3.0.0.

💡 Usage

GoDoc: https://pkg.go.dev/github.com/samber/slog-datadog/v2

Handler options

type Option struct {
	// log level (default: debug)
	Level slog.Leveler

	// datadog endpoint
	Client  *datadog.APIClient
	Context context.Context
	Timeout time.Duration	// default: 10s

	// batching (default: disabled)
	Batching      bool
	BatchDuration time.Duration // default: 5s

	// source parameters
	Service    string
	Source     string
	Hostname   string
	GlobalTags map[string]string

	// optional: customize Datadog message builder
	Converter Converter
	// optional: custom marshaler
	Marshaler func(v any) ([]byte, error)
	// optional: fetch attributes from context
	AttrFromContext []func(ctx context.Context) []slog.Attr

	// optional: see slog.HandlerOptions
	AddSource   bool
	ReplaceAttr func(groups []string, a slog.Attr) slog.Attr
}

Attributes will be injected in log payload.

Other global parameters:

slogdatadog.SourceKey = "source"
slogdatadog.ErrorKeys = []string{"error", "err"}

Example

import (
	"github.com/DataDog/datadog-api-client-go/v2/api/datadog"
	slogdatadog "github.com/samber/slog-datadog/v2"
	"log/slog"
)

func newDatadogClient(endpoint string, apiKey string) (*datadog.APIClient, context.Context) {
	ctx := datadog.NewDefaultContext(context.Background())
	ctx = context.WithValue(
		ctx,
		datadog.ContextAPIKeys,
		map[string]datadog.APIKey{"apiKeyAuth": {Key: apiKey}},
	)
	ctx = context.WithValue(
		ctx,
		datadog.ContextServerVariables,
		map[string]string{"site": endpoint},
	)
	configuration := datadog.NewConfiguration()
	apiClient := datadog.NewAPIClient(configuration)

	return apiClient, ctx
}

func main() {
	host := "1.2.3.4"
	service := "api"
	endpoint := slogdatadog.DatadogHostEU
	apiKey := "xxx"
	apiClient, ctx := newDatadogClient(endpoint, apiKey)

	logger := slog.New(slogdatadog.Option{Level: slog.LevelDebug, Client: apiClient, Context: ctx, Timeout: 5*time.Second, Hostname: host, Service: service}.NewDatadogHandler())
	logger = logger.
		With("environment", "dev").
		With("release", "v1.0.0")

	// log error
	logger.
		With("category", "sql").
		With("query.statement", "SELECT COUNT(*) FROM users;").
		With("query.duration", 1*time.Second).
		With("error", fmt.Errorf("could not count users")).
		Error("caramba!")

	// log user signup
	logger.
		With(
			slog.Group("user",
				slog.String("id", "user-123"),
				slog.Time("created_at", time.Now()),
			),
		).
		Info("user registration")
}

Batching

To improve performance and reduce network overhead, you can enable batching to send multiple log entries in a single request.

When batching is enabled, logs are buffered and sent either:

• When the batch duration elapses (configurable via BatchDuration, default: 5 seconds)
• When the buffer reaches MaxBatchSize (if configured)
• When Stop() is called to gracefully shut down

Important: Always call Stop() before your application exits to ensure all buffered logs are flushed and goroutines are properly cleaned up.

import (
	"context"
	"github.com/DataDog/datadog-api-client-go/v2/api/datadog"
	slogdatadog "github.com/samber/slog-datadog/v2"
	"log/slog"
	"time"
)

func main() {
	host := "1.2.3.4"
	service := "api"
	endpoint := slogdatadog.DatadogHostEU
	apiKey := "xxx"
	apiClient, ctx := newDatadogClient(endpoint, apiKey)

	handler := slogdatadog.Option{
		Level:         slog.LevelDebug,
		Client:        apiClient,
		Context:       ctx,
		Timeout:       5 * time.Second,
		Hostname:      host,
		Service:       service,
		Batching:      true,             // Enable batching
		BatchDuration: 10 * time.Second, // Send logs every 10 seconds (default: 5s)
	}.NewDatadogHandler()

	// Stop the batching goroutine and flush any remaining logs w/ a 5s timeout
	defer func() {
		handler.Stop(context.WithTimeout(context.Background(), 5*time.Second))
	}()

	logger := slog.New(handler)

	logger = logger.
		With("environment", "dev").
		With("release", "v1.0.0")

	// log error
	logger.
		With("category", "sql").
		With("query.statement", "SELECT COUNT(*) FROM users;").
		With("query.duration", 1*time.Second).
		With("error", fmt.Errorf("could not count users")).
		Error("caramba!")

	// log user signup
	logger.
		With(
			slog.Group("user",
				slog.String("id", "user-123"),
				slog.Time("created_at", time.Now()),
			),
		).
		Info("user registration")
}

When batching is enabled, logs are buffered in memory and sent to Datadog periodically based on BatchDuration. This significantly reduces the number of API calls and improves throughput for high-volume logging scenarios.

Tracing

Import the samber/slog-otel library.

import (
	slogdatadog "github.com/samber/slog-datadog"
	slogotel "github.com/samber/slog-otel"
	"go.opentelemetry.io/otel/sdk/trace"
)

func main() {
	tp := trace.NewTracerProvider(
		trace.WithSampler(trace.AlwaysSample()),
	)
	tracer := tp.Tracer("hello/world")

	ctx, span := tracer.Start(context.Background(), "foo")
	defer span.End()

	span.AddEvent("bar")

	logger := slog.New(
		slogdatadog.Option{
			// ...
			AttrFromContext: []func(ctx context.Context) []slog.Attr{
				slogotel.ExtractOtelAttrFromContext([]string{"tracing"}, "trace_id", "span_id"),
			},
		}.NewDatadogHandler(),
	)

	logger.ErrorContext(ctx, "a message")
}

🤝 Contributing

• Ping me on twitter @samuelberthe (DMs, mentions, whatever :))
• Fork the project
• Fix open issues or request new features

Don't hesitate ;)

# Install some dev dependencies
make tools

# Run tests
make test
# or
make watch-test

👤 Contributors

💫 Show your support

Give a ⭐️ if this project helped you!

📝 License

Copyright © 2023 Samuel Berthe.

This project is MIT licensed.