seaweedfs/weed/util/log/README.md

SeaweedFS Logging Package

This package provides a logging interface for SeaweedFS using zap as the underlying logging library. It provides a similar interface to glog while offering the performance and features of zap.

Features

• High-performance structured logging
• JSON output format
• Dynamic log level changes
• Support for both structured and unstructured logging
• Compatible with existing glog-style code
• Thread-safe

Usage

Basic Setup

import "github.com/seaweedfs/seaweedfs/weed/util/log"
import "go.uber.org/zap/zapcore"

// Initialize the logger with info level
log.Init(zapcore.InfoLevel)

Basic Logging

// Basic logging
log.Info("This is an info message")
log.Infof("This is a formatted info message: %s", "hello")
log.Warning("This is a warning message")
log.Warningf("This is a formatted warning message: %s", "hello")
log.Error("This is an error message")
log.Errorf("This is a formatted error message: %s", "hello")

Verbose Logging

// Using V for verbose logging
if log.V(1) {
    log.Info("This is a verbose message")
}

Structured Logging

// Using structured logging
logger := log.With(
    zap.String("service", "example"),
    zap.Int("version", 1),
)
logger.Info("This is a structured log message")

// Using sugared logger with fields
sugar := log.WithSugar("service", "example", "version", 1)
sugar.Infof("This is a sugared log message with fields: %s", "hello")

Fatal Logging

// Fatal logging (will exit the program)
log.Fatal("This is a fatal message")
log.Fatalf("This is a formatted fatal message: %s", "hello")

Log Levels

The package supports the following log levels:

• Debug (-1)
• Info (0)
• Warning (1)
• Error (2)
• Fatal (3)

Migration from glog

To migrate from glog to this package:

1. Replace import "github.com/golang/glog" with import "github.com/seaweedfs/seaweedfs/weed/util/log"
2. Replace glog function calls with their log package equivalents:
   • glog.Info -> log.Info
   • glog.Infof -> log.Infof
   • glog.Warning -> log.Warning
   • glog.Warningf -> log.Warningf
   • glog.Error -> log.Error
   • glog.Errorf -> log.Errorf
   • glog.Fatal -> log.Fatal
   • glog.Fatalf -> log.Fatalf
   • glog.V(level) -> log.V(level)

Example

See the example directory for a complete example of how to use the logging package.