dl_03_formatters

dl_03_formatters - output formatting options

this example demonstrates the different output formatting options available in dl (dynamic logging): pretty console output, structured json, and custom formatting patterns.

key concepts

• pretty formatting: human-readable colored output with timestamps and structured fields
• json formatting: machine-readable structured output for log aggregation systems
• custom formatting: configurable output patterns and field layouts
• contextual formatting: format selection based on destination (console vs file vs network)

formatting modes demonstrated

• pretty mode: colored, timestamped, human-readable (default for console)
• json mode: structured json output (ideal for log aggregation)
• compact mode: minimal output for high-volume logging
• custom patterns: user-defined output formats

usage

go run main.go

output examples

pretty format (console)

2024-01-15 14:30:25 [INFO] user authenticated user_id=123 username=john_doe session_id=abc123
2024-01-15 14:30:26 [ERROR] database connection failed host=db.example.com port=5432 error="connection timeout"

json format (aggregation)

{"timestamp":"2024-01-15T14:30:25Z","level":"INFO","message":"user authenticated","user_id":123,"username":"john_doe","session_id":"abc123"}
{"timestamp":"2024-01-15T14:30:26Z","level":"ERROR","message":"database connection failed","host":"db.example.com","port":5432,"error":"connection timeout"}

compact format (high volume)

INFO user_authenticated user_id=123
ERROR db_connection_failed host=db.example.com

this example shows how to configure different formatters for different use cases and destinations, enabling optimal log output for both human operators and automated systems.