slog

A simple CLI tool for structured logging with configurable levels and file output.

Features

• Configurable log levels with short flag mapping
• Configurable default log level for messages without explicit level
• Plain text structured output format
• Persistent configuration storage
• UTF-8 message validation
• Cross-platform file handling

Installation

Option 1: Download binary

Download the pre-built binary for your platform from the GitHub Releases page:

# Example for Linux (amd64)
curl -L https://github.com/natrimmer/slog/releases/latest/download/slog_linux_amd64 -o slog
chmod +x slog
sudo mv slog /usr/local/bin/

# Example for macOS (intel)
curl -L https://github.com/natrimmer/slog/releases/latest/download/slog_darwin_amd64 -o slog
chmod +x slog
sudo mv slog /usr/local/bin/

# Example for macOS (Apple Silicon)
curl -L https://github.com/natrimmer/slog/releases/latest/download/slog_darwin_arm64 -o slog
chmod +x slog
sudo mv slog /usr/local/bin/

Option 2: Using Go

go install github.com/natrimmer/slog@latest

Option 3: Build from source

git clone https://github.com/natrimmer/slog.git
cd slog
go build

Quick Start

# Get help
slog

# Configure logging
slog config --file /var/log/app.log --levels "info:i,warn:w,error:e"

# Log a message
slog "Application started"

# Log with specific level
slog -e "Database connection failed"

# View current configuration and usage
slog config

# View log file contents
slog view

Commands

Help and Version

slog              # Show help
slog --help       # Show help
slog --version    # Show version info

Configuration

# Show current configuration and usage
slog config

# Configure log file, levels, and default level (long form)
slog config --file /path/to/logfile.log --levels "debug:d,info:i,warn:w,error:e" --default info

# Configure log file, levels, and default level (short form)
slog config -f /path/to/logfile.log -l "debug:d,info:i,warn:w,error:e" -d info

# Configure only log file (keeps existing levels)
slog config --file /var/log/app.log

# Configure only levels (keeps existing file and default)
slog config --levels "info:i,error:e"

# Configure only default level (keeps existing file and levels)
slog config --default warn

Viewing

# View log file contents
slog view

# View log file contents without header (quiet mode)
slog view --quiet
slog view -q

Logging

# Log message with configured default level
slog "Your message here"

# Log with specific level using short flags
slog -d "Debug information"
slog -i "Info message"
slog -w "Warning message"
slog -e "Error occurred"

# Log with specific level using long flags
slog --debug "Debug information"
slog --info "Info message"
slog --warn "Warning message"
slog --error "Error occurred"

Log Levels

Log levels are configured via the --levels flag using the format level:flag. Any level name can be used, but common ones include:

• debug:d - Detailed diagnostic information
• info:i - General information messages
• warn:w - Warning messages
• error:e - Error messages

Note: The tool does not filter by configured levels - it accepts any level for logging.

Example Usage

Initial Setup

$ slog config --file /var/log/myapp.log --levels "info:i,warn:w,error:e" --default info
Configuration saved successfully.

$ slog config
Current Configuration:
Log File: /var/log/myapp.log
Log Levels: map[error:e info:i warn:w]
Default Level: info

Configuration Usage:
Set configuration:
  slog config --file <path> --levels <level:flag,...> --default <level>
  slog config -f <path> -l <level:flag,...> -d <level>

Logging Messages

$ slog "Application started successfully"
Logged to /var/log/myapp.log

$ slog -w "Database connection timeout"
Logged to /var/log/myapp.log

$ slog --error "Failed to process request"
Logged to /var/log/myapp.log

Viewing Log File Contents

$ slog view
Log file contents: /var/log/myapp.log

[2024-01-15 10:30:00] INFO: Application started successfully
[2024-01-15 10:31:00] WARN: Database connection timeout
[2024-01-15 10:32:00] ERROR: Failed to process request

$ slog view --quiet
[2024-01-15 10:30:00] INFO: Application started successfully
[2024-01-15 10:31:00] WARN: Database connection timeout
[2024-01-15 10:32:00] ERROR: Failed to process request

Output Format

Logs are written in plain text format:

[2006-01-02 15:04:05] INFO: Application started successfully
[2006-01-02 15:04:05] WARN: Database connection timeout
[2006-01-02 15:04:05] ERROR: Failed to process request

Configuration Storage

Configuration is stored in ~/.slog/config.json:

{
  "log_file": "/var/log/myapp.log",
  "log_levels": {
    "debug": "d",
    "info": "i",
    "warn": "w",
    "error": "e"
  },
  "default_level": "info"
}

Development

Building from Source

git clone https://github.com/natrimmer/slog.git
cd slog

# Run tests
go test

# Run tests with coverage
go test -cover

# Build
go build

# Run linter (if available)
golangci-lint run