dalog 0.2.0

Your friendly terminal logs viewer

dalog - Your friendly terminal logs viewer

dalog is a terminal-based log viewing application built with Python and Textual. It provides advanced features for viewing, searching, and analyzing log files with a modern, keyboard-driven interface optimized for developer workflows.

Features

• Live Search: Real-time filtering
• SSH Support: Read remote logs via SSH
• Exclusion System: Filter out unwanted log entries with persistent patterns and regex
• Smart Styling: Pattern-based syntax highlighting with regex support
• Live Reload: Automatically update when log files change (like tail -f) - supports both local and SSH files
• Visual Mode: Visual line selection with clipboard support
• HTML Rendering: Configurable rendering of HTML tags in logs
• Vim Keybindings: Full vim-style navigation with customizable keybindings
• Theme Support: Choose from built-in Textual themes via CLI

Installation

Via pip (recommended)

pip install dalog

Development Installation

# Clone the repository
git clone https://github.com/mwmdev/dalog.git
cd dalog

# Install in development mode
pip install -e .

# Or with development dependencies
pip install -e ".[dev]"

Quick Start

Basic Usage

# View a single log file
dalog application.log

# View a remote log file via SSH
dalog user@server:/var/log/application.log

# Start with search pre-filled
dalog --search ERROR application.log

# Search in remote logs
dalog --search ERROR user@server:/var/log/app.log

# Exclude unwanted log levels
dalog --exclude "WARNING" application.log

# Load only last 1000 lines (works with SSH too!)
dalog --tail 1000 user@server:/var/log/large-application.log

# Use custom configuration
dalog --config ~/.config/dalog/custom.toml app.log

# Use a specific Textual theme
dalog --theme gruvbox error.log

# Combine multiple options with SSH
dalog --search ERROR --exclude DEBUG --tail 500 user@host:/var/log/app.log

CLI Arguments

Required Arguments

• log_file - The path to the log file you want to view (local or SSH)
  • Local files: Must be an existing, readable file
  • SSH format: user@host:/path/to/log or ssh://user@host:port/path/to/log
  • Examples:
    • dalog application.log
    • dalog /var/log/app.log
    • dalog user@server:/var/log/nginx/access.log
    • dalog admin@192.168.1.10:2222:/logs/app.log

Optional Arguments

• --config / -c - Specify a custom configuration file

  • Type: Path to existing TOML configuration file
  • Example: dalog --config ~/.config/dalog/custom.toml app.log
  • If not specified, dalog searches for config files in the standard locations

• --search / -s - Start dalog with a search term already applied

  • Type: String (search term or regex pattern)
  • Example: dalog --search "ERROR" app.log
  • Example: dalog -s "user_id=\\d+" app.log (regex pattern)

• --tail / -t - Load only the last N lines from the file

  • Type: Integer (number of lines)
  • Useful for large log files to improve startup performance
  • Example: dalog --tail 1000 large-app.log
  • Example: dalog -t 500 app.log

• --theme - Set the visual theme for the application

  • Type: String (theme name)
  • Available themes include: textual-dark, textual-light, nord, gruvbox, catppuccin-mocha, dracula, tokyo-night, monokai, flexoki, catppuccin-latte, solarized-light
  • Example: dalog --theme gruvbox app.log
  • Example: dalog --theme nord error.log

• --exclude / -e - Exclude lines matching the specified pattern

  • Type: String (pattern or regex)
  • Can be used multiple times to exclude multiple patterns
  • Patterns are case-sensitive and support regex
  • Applied in addition to config file exclusions
  • Example: dalog --exclude "DEBUG" app.log
  • Example: dalog -e "WARNING" -e "INFO" app.log
  • Example: dalog --exclude "ERROR.*timeout" app.log (regex)

• --version / -V - Display the version number and exit

  • Example: dalog --version
  • Example: dalog -V

Default Keybindings

Key	Action
/	Open search
ESC	Close search/cancel/exit visual mode
j/k	Navigate down/up
h/l	Navigate left/right
g/G	Go to top/bottom
Ctrl+u/Ctrl+d	Page up/down
V	Enter visual line mode (vi-style selection)
v	Start selection at cursor (in visual mode)
y	Yank/copy selected lines to clipboard (in visual mode)
r	Reload file
L	Toggle live reload
w	Toggle text wrapping
e	Manage exclusions
q	Quit

Visual Mode

dalog supports vi-style visual line selection:

1. Press V (or enter a line number and press V) to enter visual line mode
2. Use j/k to navigate to the desired starting line (cursor shown with underline)
3. Press v to start selection from the current cursor position
4. Use j/k to extend the selection up/down
5. Press y to yank (copy) selected lines to clipboard
6. Press ESC to exit visual mode without copying

SSH Support

dalog can read log files from remote servers via SSH. This is particularly useful for:

• Monitoring production logs without logging into servers
• Viewing logs from multiple servers in separate terminal windows
• Applying your local dalog configuration to remote logs

SSH URL Format

user@host:/path/to/log
user@host:port:/path/to/log
ssh://user@host:port/path/to/log

SSH Authentication

dalog uses your system's SSH configuration:

• SSH keys from ~/.ssh/
• SSH agent for key management
• SSH config from ~/.ssh/config

Live Reload for SSH

Live reload works with SSH files! dalog will periodically check for changes and automatically update the display when the remote file is modified.

Examples

# View nginx access logs on web server
dalog webadmin@webserver:/var/log/nginx/access.log

# Monitor application errors with filtering
dalog --search ERROR --exclude DEBUG deploy@app-server:/home/app/logs/production.log

# Tail last 500 lines from remote syslog
dalog --tail 500 root@192.168.1.1:/var/log/syslog

# Use custom port
dalog admin@server:2222:/var/log/custom.log

Configuration

dalog looks for configuration files in the following order:

1. Command-line specified: --config path/to/config.toml
2. $XDG_CONFIG_HOME/dalog/config.toml
3. ~/.config/dalog/config.toml
4. ~/.dalog.toml
5. ./config.toml (current directory)

Example Configuration

[app]
default_tail_lines = 1000
live_reload = true
case_sensitive_search = false
vim_mode = true

[keybindings]
search = "/"
reload = "r"
toggle_live_reload = "L"
toggle_wrap = "w"
quit = "q"
show_exclusions = "e"
scroll_down = "j"
scroll_up = "k"
scroll_left = "h"
scroll_right = "l"
scroll_home = "g"
scroll_end = "G"

[display]
show_line_numbers = true
wrap_lines = false
max_line_length = 1000
visual_mode_bg = "white"  # Background color for visual mode selection

[styling.patterns]
error = { pattern = "(?i)error", background = "red", color = "white" }
warning = { pattern = "(?i)warning", background = "yellow", color = "black", bold = true }
info = { pattern = "(?i)info", color = "blue" }

[styling.timestamps]
iso_datetime = { pattern = "\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}", color = "cyan" }

[html]
# Configure which HTML tags to render in logs
enabled_tags = ["b", "i", "em", "strong", "span", "code", "pre"]
strip_unknown_tags = true

[exclusions]
patterns = ["DEBUG:", "TRACE:"]
regex = true
case_sensitive = false

Styling System

dalog supports powerful regex-based styling patterns:

[styling.custom]
# Highlight IP addresses
ip_address = { pattern = "\\b(?:[0-9]{1,3}\\.){3}[0-9]{1,3}\\b", color = "magenta" }

# Highlight URLs
url = { pattern = "https?://[\\w\\.-]+", color = "blue", underline = true }

# Highlight email addresses
email = { pattern = "\\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Z|a-z]{2,}\\b", color = "cyan" }

# Custom application-specific patterns
user_id = { pattern = "user_id=\\d+", color = "green", bold = true }

Development

Setting up the development environment

# Clone the repository
git clone https://github.com/mwmdev/dalog.git
cd dalog

# Install development dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Run linting
black src/
mypy src/
pylint src/

Project Structure

dalog/
├── src/dalog/          # Main package
│   ├── app.py          # Textual application
│   ├── cli.py          # Click CLI interface
│   ├── config/         # Configuration management
│   ├── core/           # Core functionality
│   ├── widgets/        # Custom Textual widgets
│   └── styles/         # CSS styles
├── tests/              # Test suite
├── docs/               # Documentation
└── pyproject.toml      # Project configuration

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Built with Textual - an amazing TUI framework
• Inspired by traditional Unix tools like tail, less, and grep
• Thanks to all contributors and users