slog: Zap handler

A zap Handler for slog Go library.

^{Sponsored by:}

Cloud-native search engine for observability - An OSS alternative to Splunk, Elasticsearch, Loki, and Tempo.

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-zap/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-zap/v2

Handler options

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

	// optional: zap logger (default: zap.L())
	Logger *zap.Logger

	// optional: customize json payload builder
	Converter Converter
    // 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
}

Other global parameters:

slogzap.SourceKey = "source"
slogzap.ErrorKeys = []string{"error", "err"}
slogzap.LogLevels = map[slog.Level]zapcore.Level{...}

Example

import (
    slogzap "github.com/samber/slog-zap/v2"
    "go.uber.org/zap"
    "log/slog"
)

func main() {
    zapLogger, _ := zap.NewProduction()

    logger := slog.New(slogzap.Option{Level: slog.LevelDebug, Logger: zapLogger}.NewZapHandler())
    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")
}

Tracing

Import the samber/slog-otel library.

import (
	slogzap "github.com/samber/slog-zap"
	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(
		slogzap.Option{
			// ...
			AttrFromContext: []func(ctx context.Context) []slog.Attr{
				slogotel.ExtractOtelAttrFromContext([]string{"tracing"}, "trace_id", "span_id"),
			},
		}.NewZapHandler(),
	)

	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

samber/slog-zap