GitHub - samber/slog-logstash: 🚨 slog: Logstash handler (original) (raw)

slog: Logstash handler

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A Logstash Handler for slog Go library.

See also:

HTTP middlewares:

Loggers:

Log sinks:

🚀 Install

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

Handler options

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

// connection to logstash
Conn net.Conn

// optional: customize json payload 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:

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

Example

import ( pool "github.com/samber/go-tcp-pool" sloglogstash "github.com/samber/slog-logstash/v2" "log/slog" )

func main() { // ncat -l 9999 -k conn, err := pool.Dial("tcp", "localhost:9999") if err != nil { log.Fatal(err) }

logger := slog.New(sloglogstash.Option{Level: slog.LevelDebug, Conn: conn}.NewLogstashHandler())
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")

}

Output:

{ "@timestamp":"2023-04-10T14:00:0.000000+00:00", "level":"ERROR", "message":"caramba!", "error":{ "error":"could not count users", "kind":"errors.errorString", "stack":null }, "extra":{ "environment":"dev", "release":"v1.0.0", "category":"sql", "query.statement":"SELECT COUNT() FROM users;", "query.duration": "1s" } }

{ "@timestamp":"2023-04-10T14:00:0.000000+00:00", "level":"INFO", "message":"user registration", "error":null, "extra":{ "environment":"dev", "release":"v1.0.0", "user":{ "id":"user-123", "created_at":"2023-04-10T14:00:0.000000+00:00" } } }

Tracing

Import the samber/slog-otel library.

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

logger.ErrorContext(ctx, "a message")

}

🤝 Contributing

Don't hesitate ;)

Install some dev dependencies

make tools

Run tests

make test

or

make watch-test

👤 Contributors

Contributors

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📝 License

Copyright © 2023 Samuel Berthe.

This project is MIT licensed.