README
¶
Logger Package
A structured logging package built on top of uber-go/zap, providing both global and context-aware logging capabilities with sensible defaults.
Features
- Built on top of the high-performance zap logger
- Supports both structured and printf-style logging
- Context-aware logging
- Global and instance-based logging
- Configurable log levels and encoding formats
- Request ID tracking support
- Easy integration with existing applications
Installation
go get -u github.com/zondax/golem/pkg/logger
Quick Start
// Initialize with default configuration
logger.InitLogger(logger.Config{
Level: "info",
Encoding: "json",
})
// Basic logging
logger.Info("Server started")
logger.Error("Connection failed")
// Structured logging with fields
log := logger.NewLogger(
logger.Field{Key: "service", Value: "api"},
logger.Field{Key: "version", Value: "1.0.0"},
)
log.Info("Service initialized")
Configuration
Logger Config
type Config struct {
Level string `json:"level"` // Logging level
Encoding string `json:"encoding"` // Output format
}
Log Levels
Available log levels (in order of increasing severity):
debug: Detailed information for debugginginfo: General operational informationwarn: Warning messages for potentially harmful situationserror: Error conditions that should be addresseddpanic: Critical errors in development that cause panicpanic: Critical errors that cause panic in productionfatal: Fatal errors that terminate the program
Encoding Formats
-
JSON Format (Default)
- Recommended for production
- Machine-readable structured output
{"level":"INFO","ts":"2024-03-20T10:00:00.000Z","msg":"Server started","service":"api"} -
Console Format
- Recommended for development
- Human-readable output
2024-03-20T10:00:00.000Z INFO Server started service=api
Advanced Usage
Context-Aware Logging
// Create a context with logger
ctx := context.Background()
log := logger.NewLogger(logger.Field{
Key: logger.RequestIDKey,
Value: "req-123",
})
ctx = logger.ContextWithLogger(ctx, log)
// Get logger from context
contextLogger := logger.GetLoggerFromContext(ctx)
contextLogger.Info("Processing request")
Structured Logging with Fields
log := logger.NewLogger()
log.WithFields(
zap.String("user_id", "12345"),
zap.String("action", "login"),
zap.Int("attempt", 1),
).Info("User login attempt")
Printf-Style Logging
logger.Infof("Processing item %d of %d", current, total)
logger.Errorf("Failed to connect to %s: %v", host, err)
Best Practices
-
Use Structured Logging
// Good log.WithFields( zap.String("user_id", "12345"), zap.String("action", "purchase"), zap.Float64("amount", 99.99), ).Info("Purchase completed") // Avoid log.Infof("User %s completed purchase of $%.2f", userID, amount) -
Include Request IDs
log.WithFields( zap.String(logger.RequestIDKey, requestID), ).Info("Handling request") -
Proper Error Logging
if err != nil { log.WithFields( zap.Error(err), zap.String("operation", "database_query"), ).Error("Query failed") } -
Resource Cleanup
defer logger.Sync()
Performance Considerations
- The logger is designed to be zero-allocation in most cases
- JSON encoding is more CPU-intensive but provides structured data
- Log level checks are performed atomically
- Field allocation is optimized for minimal overhead
Thread Safety
The logger is completely thread-safe and can be used concurrently from multiple goroutines.
Documentation
¶
Index ¶
- Constants
- func ContextWithLogger(ctx context.Context, logger *Logger) context.Context
- func DPanic(msg string)
- func DPanicf(template string, args ...interface{})
- func Debug(msg string)
- func Debugf(template string, args ...interface{})
- func Error(msg string)
- func Errorf(template string, args ...interface{})
- func Fatal(msg string)
- func Fatalf(template string, args ...interface{})
- func Info(msg string)
- func Infof(template string, args ...interface{})
- func InitLogger(config Config)
- func L() *zap.Logger
- func Panic(msg string)
- func Panicf(template string, args ...interface{})
- func ReplaceGlobals(logger *zap.Logger) func()
- func S() *zap.SugaredLogger
- func SetGlobalConfig(config Config) func()
- func Sync() error
- func Warn(msg string)
- func Warnf(template string, args ...interface{})
- type Config
- type Field
- type Logger
- func (l *Logger) DPanic(msg string)
- func (l *Logger) DPanicf(template string, args ...interface{})
- func (l *Logger) Debug(msg string)
- func (l *Logger) Debugf(template string, args ...interface{})
- func (l *Logger) Error(msg string)
- func (l *Logger) Errorf(template string, args ...interface{})
- func (l *Logger) Fatal(msg string)
- func (l *Logger) Fatalf(template string, args ...interface{})
- func (l *Logger) Info(msg string)
- func (l *Logger) Infof(template string, args ...interface{})
- func (l *Logger) IsDebugEnabled() bool
- func (l *Logger) Panic(msg string)
- func (l *Logger) Panicf(template string, args ...interface{})
- func (l *Logger) Warn(msg string)
- func (l *Logger) Warnf(template string, args ...interface{})
- func (l *Logger) WithFields(fields ...zap.Field) *Logger
Constants ¶
View Source
const (
ConsoleEncode = "console"
)
View Source
const (
RequestIDKey = "request_id"
)
Variables ¶
This section is empty.
Functions ¶
func ContextWithLogger ¶
func InitLogger ¶
func InitLogger(config Config)
func ReplaceGlobals ¶ added in v0.19.2
func S ¶ added in v0.19.2
func S() *zap.SugaredLogger
func SetGlobalConfig ¶ added in v0.19.2
func SetGlobalConfig(config Config) func()
Types ¶
type Logger ¶
type Logger struct {
// contains filtered or unexported fields
}
func GetLoggerFromContext ¶
func (*Logger) IsDebugEnabled ¶ added in v0.15.1
Source Files
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