slogctx

slogctx is a Go package that extends the standard log/slog package with context-aware attribute management. It allows you to attach logging attributes to a context.Context and have them automatically included in log records.

Features

• Attach logging attributes to context.Context
• Automatically include context attributes in log records
• Compatible with standard log/slog handlers
• Zero external dependencies
• Clean and simple API

Compared to the other similar slogctx packages, this package has the following differences:

• Attributes added later are considered more specific and are output first
• Attributes in a context is resettable and has affinity with slog.Logger.WithGroup
• Append-like attribute getter

Usage

Basic Usage

// Create a context with logging attributes
ctx := context.Background()
ctx = slogctx.With(ctx, "user", "alice", slog.Int("age", 42))
ctx = slogctx.With(ctx, "requestID", "req-123")

// Create a logger with the context-aware handler
logger := slog.New(slogctx.NewHandler(slog.Default().Handler()))

// Log with context - attributes will be automatically included
logger.InfoContext(ctx, "User action performed", "action", "login")
// Output: level=INFO msg="User action performed" action=login user=alice age=42 requestID=req-123

Manual Attribute Access

// Get attributes from context explicitly
logger.Info("User action performed", slogctx.Attrs(ctx, "action", "login")...)

Reset Context Attributes

// Create new context without inherited attributes
newCtx := slogctx.Reset(ctx, "fresh", "start")

Best Practices

1. Use With to attach common attributes at middleware or high-level handlers
2. Pass the context through your application's call chain
3. Use NewHandler to automatically include context attributes in logs
4. Use Reset when you need to start fresh with new attributes
5. Use Attrs when you need manual control over attribute inclusion