Log--

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Regex-based log viewer for VS Code - color highlighting, auto-folding, keyword timeline, code grep, and AI-assisted configuration.

Overview

Log-- turns VS Code into a powerful log analysis tool. Define regex groups to color-code log lines, auto-fold irrelevant content, highlight keywords with substring-level coloring, and visualize keyword hit distribution on a timeline — all triggered by a single Go button.

Designed for debugging large log files: Android logcat, kernel logs, application traces, and more.

Features

🎨 Regex Group Coloring & Auto-Folding

Define multiple regex groups, each with a color and one or more expressions (combined with AND / OR / NOT logic). Matched lines get full-line color highlights. Unmatched lines are automatically folded so only relevant content stays visible.

• First-match-wins priority (groups evaluated top-to-bottom)
• Per-expression flags (case-insensitive, multiline, dotAll)
• Fold annotations show hidden line count + time span
• Switching files preserves your fold state within the session

🔍 Keyword Substring Highlighting

Keywords highlight specific substrings within visible lines, using range subtraction so they never clash with group colors.

• Named capture support: use (?<name>...) in the pattern, then reference captures in hints with {{name}} — the hint displays the actual matched value per line
• Per-keyword scope:
  • matched — only highlight within group-matched lines
  • full — scan all lines; keyword-only lines stay visible and are not folded (acts like an additional filter group)
• Per-keyword ↑/↓ navigation buttons to jump between that keyword's hits
• Live count badges showing match counts per keyword

Named capture example:

• Pattern: (?<pid>\d+)\s+(?<tag>\w+):
• Hint: pid={{pid}} tag={{tag}}
• Result on line 1234 MyTag: message: displays pid=1234 tag=MyTag

⏱️ Time Annotations & Auto-Detection

Configure a time format, or leave it empty for auto-detection. Supported formats:

Each folded region displays: ▼ N lines │ ~duration │ +elapsed

📊 Keyword Timeline

Canvas-based timeline chart embedded in the sidebar, showing when each keyword hit occurs over time.

• Scroll-wheel zoom — zoom in/out at mouse position with smart tick count and sub-grid
• Hover tooltip — shows keyword name, time offset, line number, and the matched substring
• Click to jump — click any point to navigate to that line in the editor
• Auto-resize — CSS-driven canvas sizing with 100ms polling fallback for VS Code panel changes
• Time axis starts from the log's first timestamp (or ring-buffer wrap point)

🚩 Ring Buffer Detection

Detects wrap-around in ring-buffer logs (where timestamps reset). The detected start line is marked with a red flag icon and protected from folding.

🖱️ Right-Click Grep

Select text in any file → right-click → Grep Keyword / Grep Function:

• Searches associated code directories (configured per regex group via associatedDirs)
• Output to terminal with >>> delimiters
• Supports ;-separated multiple directories, ! exclusion, ${VAR} environment variables
• Grep Function finds multi-line function definitions across files

📤 Export Matched Lines

Click Export to copy all matched lines to a new unsaved editor (<filename>_matched{n}):

• Named after the source file with a counter
• Set to log language for syntax highlighting
• Ideal for large files where VS Code disables folding

💾 Config Sharing & Management

• Save / Apply / Delete named configs (User or Workspace scope)
• Export / Import as JSON files
• Configs persist across sessions via VS Code's workspace/global state

🤖 AI-Assisted Configuration

Log-- ships with an Agent Skill that lets AI agents (like Pi, Claude Code, or any Agent Skills-compatible tool) automatically configure filter groups, keywords, and time patterns for any log format.

How It Works

1. On install/update, the extension copies SKILL.md to ~/.agents/skills/log-config/
2. The AI agent reads the skill, analyzes your sample log lines, and generates a config JSON
3. The agent writes the config to ~/.agents/log-configs/<name>.json
4. The config automatically appears in the Solution dropdown in the sidebar
5. You just select it and click Apply — no manual import needed

Example: Agent Workflow

# The agent writes a config file:
mkdir -p ~/.agents/log-configs
cat > ~/.agents/log-configs/android-crash.json << 'EOF'
{
  "groups": [
    { "id": "g1", "name": "Fatal", "color": "#ff0000",
      "expressions": [{"id":"e1","pattern":"FATAL|ASSERT","flags":"","operator":"and"}] },
    { "id": "g2", "name": "Error", "color": "#ff6600",
      "expressions": [{"id":"e2","pattern":" E /|ERROR","flags":"","operator":"and"}] }
  ],
  "timePattern": { "format": "MM-DD HH:mm:ss.SSS" },
  "keywords": [
    { "id": "kw1", "pattern": "ANR in (?<app>\\S+)", "flags": "",
      "color": "#ff00ff", "matchScope": "full", "hint": "ANR: {{app}}" }
  ]
}
EOF

The config android-crash appears in the Solution dropdown as (file) scope. Click Apply to load it, then Go to filter.

Skill Content

The bundled skill (skills/log-config/SKILL.md) includes:

• Step-by-step configuration procedure for AI agents
• Common regex patterns by log type (Android, kernel, generic)
• Named capture hint syntax with practical examples
• Config JSON structure reference
• Large file handling guidelines
• Pitfalls and verification steps

📏 Large File Support

For very large logs (e.g. 1M+ line Android dumps), use Export to extract matched lines into a smaller editor where folding works.

Usage

1. Open a log file in VS Code
2. Configure regex groups and keywords in the Log-- sidebar
   • Or use Solution dropdown to apply a saved/agent-generated config
3. Click Go — matched lines get colored, unmatched lines fold
4. Navigate — use ↑/↓ on keywords to jump between hits; scroll-wheel on timeline to zoom
5. Export — click Export to copy matched lines to a new editor

Installation

Search "Log--" in VS Code Extensions, or install from Marketplace.

Development

git clone <repo-url>
cd log-minus-minus
npm install
npm test          # 204 unit tests
npx tsc --noEmit  # type check
# Press F5 in VS Code to launch extension debug host

Architecture

MVC layered architecture:

• Model: RegexGroupModel, FilterResultModel, TimeMatchModel, ConfigStorageModel, RingBufferModel
• Controller: FilterController (regex engine), GrepController (code search), ViewController (orchestrator)
• View: ConfigPanel (sidebar webview with inline timeline), EditorDecorations (highlight/fold annotations)

Key Design Decisions

• FoldingRangeProvider for declarative folding (not manual createFoldingRangeFromSelection)
• WebviewViewProvider for sidebar (doesn't steal editor focus)
• Go button triggers all effects — no auto-apply on activation or editor switch
• Session-aware attach: switching back to a filtered file preserves your fold state

License

MIT