Logging

Structured logging with slog, multiple output formats, and file support.

RapidGo uses Go's standard log/slog package for structured logging with configurable levels, formats, and outputs.

Configuration

LOG_LEVEL=debug    # debug, info, warn, error
LOG_FORMAT=json    # json, text
LOG_OUTPUT=stdout  # stdout, file

Setup

The logger is configured automatically by the LoggerProvider:

import "github.com/RAiWorks/RapidGo/v2/core/logger"

// Called by LoggerProvider — sets slog.SetDefault()
log := logger.Setup()

After setup, use slog anywhere in your application:

import "log/slog"

slog.Info("user registered", "user_id", user.ID, "email", user.Email)
slog.Error("payment failed", "order_id", order.ID, "error", err)
slog.Debug("cache hit", "key", cacheKey)
slog.Warn("rate limit approaching", "ip", clientIP, "count", count)

Log Levels

Level	Description
`debug`	Verbose development information
`info`	General operational events
`warn`	Potential issues that aren't errors
`error`	Errors that need attention

Output Formats

JSON (default)

{"time":"2026-01-15T10:30:00Z","level":"INFO","msg":"user registered","user_id":42,"email":"user@example.com"}

Text

time=2026-01-15T10:30:00Z level=INFO msg="user registered" user_id=42 email=user@example.com

File Output

When LOG_OUTPUT=file, logs are written to storage/logs/app.log. The directory is created automatically. Call logger.Close() on shutdown to flush and close the file handle.