dynamic-level-handler

Golang wrapper for slog.Handler that supports level override for concrete logger. This functionality was originally implemented in Neptunus to support different logging levels of pipelines and plugins.

But... Why?

Have you ever wanted to enable only warnings or errors for specific parts of an application? And then enable debug for those concrete parts? I have. This package was created with that idea in mind.

DynamicHandlerWrapper wraps the passed slog.Handler and allows you to set a personal logging level via slog.Leveler. If level has not been overridden, all calls are passed to the basic handler.

Examples

import (
	"log/slog"

	dynamic "github.com/gekatateam/dynamic-level-handler"
)

// create basic handler
h := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
    Level: slog.LevelInfo
})

// wrap basic handler
dynamicHandler := dynamic.New(h)

// create common logger for all app
logger := slog.New(dynamicHandler)

......

// create child logger with some attributes
// then override it's level
pipelineLogger := logger.With(slog.Group("pipeline",
    "id", "cronjobs",
))
// you don't need to think about what specific handler type is passed here
// this function only does something if handler type is `DynamicLevelHandler`
dynamic.OverrideLevel(pipelineLogger.Handler(), slog.LevelWarn)

......

// create another child logger, set it's personal level
pluginLogger := pipelineLogger.log.With(slog.Group("input",
    "plugin", "cronjob",
    "name", "first cron",
))
dynamic.OverrideLevel(pluginLogger.Handler(), slog.LevelDebug)