http middleware for slog logger (original) (raw)

slog: net/http middleware

net/http handler to log HTTP requests using slog.

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-http

Compatibility: go >= 1.21

No breaking changes will be made to exported APIs before v2.0.0.

💡 Usage

Handler options

type Config struct { DefaultLevel slog.Level ClientErrorLevel slog.Level ServerErrorLevel slog.Level

WithUserAgent      bool
WithRequestID      bool
WithRequestBody    bool
WithRequestHeader  bool
WithResponseBody   bool
WithResponseHeader bool
WithSpanID         bool
WithTraceID        bool

Filters []Filter

}

Attributes will be injected in log payload.

Other global parameters:

sloghttp.TraceIDKey = "trace_id" sloghttp.SpanIDKey = "span_id" sloghttp.RequestBodyMaxSize = 64 * 1024 // 64KB sloghttp.ResponseBodyMaxSize = 64 * 1024 // 64KB sloghttp.HiddenRequestHeaders = map[string]struct{}{ ... } sloghttp.HiddenResponseHeaders = map[string]struct{}{ ... } sloghttp.RequestIDHeaderKey = "X-Request-Id"

Minimal

import ( "net/http" "os" "time"

sloghttp "github.com/samber/slog-http"
"log/slog"

)

// Create a slog logger, which: // - Logs to stdout. logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

// mux router mux := http.NewServeMux()

// Routes mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Write([]byte("Hello, World!")) })) mux.Handle("/error", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { http.Error(w, "I'm angry" http.StatusInternalServerError) }))

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.New(logger)(handler)

// Start server http.ListenAndServe(":4242", handler)

// output: // time=2023-10-15T20:32:58.926+02:00 level=INFO msg="Success" env=production request.time=2023-10-15T20:32:58.626+02:00 request.method=GET request.path=/ request.route="" request.ip=127.0.0.1:63932 request.length=0 response.time=2023-10-15T20:32:58.926+02:00 response.latency=100ms response.status=200 response.length=7 id=229c7fc8-64f5-4467-bc4a-940700503b0d

OTEL

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

config := sloghttp.Config{ WithSpanID: true, WithTraceID: true, }

mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.NewWithConfig(logger, config)(handler)

// Start server http.ListenAndServe(":4242", handler)

Custom log levels

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

config := sloghttp.Config{ DefaultLevel: slog.LevelInfo, ClientErrorLevel: slog.LevelWarn, ServerErrorLevel: slog.LevelError, }

mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.NewWithConfig(logger, config)(handler)

// Start server http.ListenAndServe(":4242", handler)

Verbose

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

config := sloghttp.Config{ WithRequestBody: true, WithResponseBody: true, WithRequestHeader: true, WithResponseHeader: true, }

mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.NewWithConfig(logger, config)(handler)

// Start server http.ListenAndServe(":4242", handler)

Filters

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.NewWithFilters( logger, sloghttp.Accept(func (w sloghttp.WrapResponseWriter, r *http.Request) bool { return xxx }), sloghttp.IgnoreStatus(401, 404), )(handler)

// Start server http.ListenAndServe(":4242", handler)

Available filters:

Accept / Ignore
AcceptMethod / IgnoreMethod
AcceptStatus / IgnoreStatus
AcceptStatusGreaterThan / IgnoreStatusGreaterThan
AcceptStatusLessThan / IgnoreStatusLessThan
AcceptStatusGreaterThanOrEqual / IgnoreStatusGreaterThanOrEqual
AcceptStatusLessThanOrEqual / IgnoreStatusLessThanOrEqual
AcceptPath / IgnorePath
AcceptPathContains / IgnorePathContains
AcceptPathPrefix / IgnorePathPrefix
AcceptPathSuffix / IgnorePathSuffix
AcceptPathMatch / IgnorePathMatch
AcceptHost / IgnoreHost
AcceptHostContains / IgnoreHostContains
AcceptHostPrefix / IgnoreHostPrefix
AcceptHostSuffix / IgnoreHostSuffix
AcceptHostMatch / IgnoreHostMatch

Using custom time formatters

import ( "net/http" "log/slog"

sloghttp "github.com/samber/slog-http"
slogformatter "github.com/samber/slog-formatter"

)

// Create a slog logger, which: // - Logs to stdout. // - RFC3339 with UTC time format. logger := slog.New( slogformatter.NewFormatterHandler( slogformatter.TimezoneConverter(time.UTC), slogformatter.TimeFormatter(time.DateTime, nil), )( slog.NewTextHandler(os.Stdout, nil), ), )

// mux router mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.New(logger)(handler)

// Start server http.ListenAndServe(":4242", handler)

// output: // time=2023-10-15T20:32:58.926+02:00 level=INFO msg="Success" env=production request.time=2023-10-15T20:32:58Z request.method=GET request.path=/ request.route="" request.ip=127.0.0.1:63932 request.length=0 response.time=2023-10-15T20:32:58Z response.latency=100ms response.status=200 response.length=7 id=229c7fc8-64f5-4467-bc4a-940700503b0d

Using custom logger sub-group

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

// mux router mux := http.NewServeMux()

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.New(logger.WithGroup("http"))(handler)

// Start server http.ListenAndServe(":4242", handler)

// output: // time=2023-10-15T20:32:58.926+02:00 level=INFO msg="Success" env=production http.request.time=2023-10-15T20:32:58.626+02:00 http.request.method=GET http.request.path=/ http.request.route="" http.request.ip=127.0.0.1:63932 http.request.length=0 http.response.time=2023-10-15T20:32:58.926+02:00 http.response.latency=100ms http.response.status=200 http.response.length=7 http.id=229c7fc8-64f5-4467-bc4a-940700503b0d

Add logger to a single route

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

// mux router mux := http.NewServeMux()

// Routes mux.Handler("/", sloghttp.New(logger)( http.HandlerFunc( func(w http.ResponseWriter, r *http.Request) { return c.String(http.StatusOK, "Hello, World!") }, ), sloghttp.New(logger), ))

// Start server http.ListenAndServe(":4242", handler)

Adding custom attributes

logger := slog.New(slog.NewTextHandler(os.Stdout, nil))

// Add an attribute to all log entries made through this logger. logger = logger.With("env", "production")

// mux router mux := http.NewServeMux()

// Routes mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { sloghttp.AddCustomAttributes(r, slog.String("foo", "bar")) w.Write([]byte("Hello, World!")) }))

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.New(logger)(handler)

// Start server http.ListenAndServe(":4242", handler)

JSON output

logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))

// mux router mux := http.NewServeMux()

// Routes mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Write([]byte("Hello, World!")) }))

// Middleware handler := sloghttp.Recovery(mux) handler = sloghttp.New(logger)(handler)

// Start server http.ListenAndServe(":4242", handler)

// output: // {"time":"2023-10-15T20:32:58.926+02:00","level":"INFO","msg":"Success","env":"production","http":{"request":{"time":"2023-10-15T20:32:58.626+02:00","method":"GET","path":"/","route":"","ip":"127.0.0.1:55296","length":0},"response":{"time":"2023-10-15T20:32:58.926+02:00","latency":100000,"status":200,"length":7},"id":"04201917-d7ba-4b20-a3bb-2fffba5f2bd9"}}

🤝 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

This project is MIT licensed.