Tailspin — Log File Highlighter for the Terminal

Introduction

Tailspin is a Rust-based CLI tool that adds instant syntax highlighting to any log output. Unlike grep or less, Tailspin automatically detects common log patterns — timestamps, IP addresses, UUIDs, HTTP methods, URLs, log levels, and key-value pairs — and colorizes them without any configuration. It works as a drop-in replacement for tail or less when reading logs.

What Tailspin Does

• Automatically highlights dates, IPs, UUIDs, URLs, numbers, and log levels
• Works with any log format without requiring format-specific configuration
• Supports piping from any command (kubectl, docker, journalctl, cat)
• Follows log files in real time with the -f flag like tail -f
• Provides a built-in pager for scrolling through large files

Architecture Overview

Tailspin is a single Rust binary that reads input line by line and applies a series of regex-based highlighters. Each highlighter matches a specific pattern type (ISO timestamps, IPv4/IPv6, severity keywords) and wraps matches in ANSI color codes. The matching pipeline is optimized for throughput so it does not bottleneck high-volume log streams. Output is rendered to the terminal or piped through a pager.

Self-Hosting & Configuration

• Install as a single static binary; no runtime dependencies
• Custom highlight rules can be added via a TOML config file at ~/.config/tailspin/config.toml
• Override default colors by specifying custom ANSI color codes per pattern type
• Disable specific highlighters with --disable flag
• Integrates with any terminal that supports ANSI escape codes

Key Features

• Zero-config highlighting for the most common log patterns
• High-throughput line processing that keeps up with streaming logs
• Built-in pager with search support (press / to search)
• Custom highlight groups definable in TOML configuration
• Works over SSH and in containers where GUI tools are unavailable

Comparison with Similar Tools

• ccze — C-based log colorizer with format-specific parsers; Tailspin is format-agnostic
• lnav — full log navigator with indexing and SQL queries; Tailspin focuses purely on highlighting
• grc — generic colourizer using regex config files; Tailspin needs no configuration for common patterns
• bat — syntax-highlighted cat for code files; Tailspin specializes in log file patterns
• less — standard pager without colors; Tailspin adds automatic log-aware highlighting

FAQ

Q: Does Tailspin work with JSON logs? A: Yes. It highlights JSON keys, values, timestamps, and other patterns within JSON-formatted log lines.

Q: Can I use Tailspin as a pager for other commands? A: Yes. Pipe any command output through tspin to get instant highlighting with a built-in pager.

Q: Does it slow down high-volume log tailing? A: No. Tailspin is written in Rust and processes lines at speeds well above typical log throughput rates.

Q: How do I add custom patterns? A: Add regex rules and ANSI color codes to the [groups] section in ~/.config/tailspin/config.toml.

Sources

• https://github.com/bensadeh/tailspin