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

    // connection to Fluentd
    Client *fluentd.Fluentd
    Tag    string

    // 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
}

slogfluentd.SourceKey = "source"
slogfluentd.ContextKey = "extra"
slogfluentd.ErrorKeys = []string{"error", "err"}

import (
    "github.com/fluent/fluent-logger-golang/fluent"
    slogfluentd "github.com/samber/slog-fluentd/v2"
    "log/slog"
)

func main() {
    // docker-compose up -d
    client, err := fluent.New(fluent.Config{
        FluentHost:    "localhost",
        FluentPort:    24224,
        FluentNetwork: "tcp",
        MarshalAsJSON: true,
        Async:         true,
    })
    if err != nil {
        log.Fatal(err.Error())
    }


    logger := slog.New(
        slogfluentd.Option{
            Level: slog.LevelDebug,
            Client: client,
            Tag: "api",
        }.NewFluentdHandler(),
    )
    logger = logger.
        With("environment", "dev").
        With("release", "v1.0.0")

    // log error
    logger.
        With("tag", "api.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")
}

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

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