RCGen is a command-line tool for generating changelogs from Git repositories in Markdown, JSON, and plaintext formats. It's designed for developers who need informative and structured changelogs for their projects.

• Three Output Formats: Markdown, JSON, and Plaintext
• Smart Grouping: Automatically groups commits by type (feat, fix, docs, etc.)
• Full Statistics: In-depth analysis of the repository including bus factor, activity, and contributors
• Flexible Filtering: Filter commits by author, date, or message pattern
• Diff Statistics: Displays changed files, added lines, and deleted lines
• Custom Configuration: .rcgen.toml configuration file for customizing the output
• Preview Mode: Preview the changelog directly in the terminal
• Conventional Commit Detection: Supports Conventional Commits with scopes
• Tag and Branch Information: Displays the tags and branches associated with each commit

# Clone repository
$ git clone https://github.com/neuxdotdev/rcgen
$ cd rcgen
# Build and install
$ cargo install --path .

# Generate Markdown changelog
$ rcgen gen --format md --output CHANGELOG.md
# Generate with grouping and statistics
$ rcgen gen --group --stats --limit 50
# Preview the last 10 commits
$ rcgen preview
# Show repository statistics
$ rcgen stats --detailed

Generate a changelog from a Git repository. Options:

Example:

# Generate commits with author and date filters
$ rcgen gen --author "john" --since "2024-01-01" --until "2024-02-01"
# Generate JSON with all commits and statistics
$ rcgen gen --format json --limit 0 --stats
# Generate releases with grouping
$ rcgen gen --release --group --diff-stats

Show repository statistics. Options:

Example:

# Basic statistics
$ rcgen stats
# Detailed statistics in JSON
$ rcgen stats --detailed --format json
# Statistics for a specific path
$ rcgen stats --path /path/to/repo

Initialize the .$ rcgen.toml configuration file. Options:

Example:

# Initialize the default configuration
$ rcgen init
# Overwrite the existing configuration
$ rcgen init --force

Preview the changelog in the terminal. Options:

Example:

# Preview the last 10 commits
$ rcgen preview
# Preview the last 20 commits
$ rcgen preview --limit 20

Compare two revisions (not yet implemented). Options:

Example:

# Compare two tags
$ rcge diff v1.0.0 v2.0.0
# Compare commits with HEAD
$ rcgen diff abc123def

RCGen supports configuration through the .rcgen.toml file in the repository root. Run rcgen init to create the default configuration.

[filters]
exclude_authors = [ "bot@example.com" ]
exclude_patterns = [ "^Merge", "^Revert" ]
include_patterns = [ ]

[grouping]
enabled = true

  [[grouping.groups]]
  name = "Features"
  patterns = [ "^feat:", "adds?", "new" ]
  description = "New features and enhancements"

  [[grouping.groups]]
  name = "Bug Fixes"
  patterns = [ "^fix:", "bug" ]
  description = "Bug fixes and patches"

  [[grouping.groups]]
  name = "Documentation"
  patterns = [ "^docs:", "doc(?:s|umentation)?" ]
  description = "Documentation updates"

  [[grouping.groups]]
  name = "Refactoring"
  patterns = [ "^refactor:", "cleanup" ]
  description = "Code refactoring"

  [[grouping.groups]]
  name = "Performance"
  patterns = [ "^perf:", "optimize" ]
  description = "Performance improvements"

  [[grouping.groups]]
  name = "Tests"
  patterns = [ "^test:", "^tests:" ]
  description = "Test updates"

  [[grouping.groups]]
  name = "Chores"
  patterns = [ "^chore:", "^ci:", "^build:" ]
  description = "Maintenance tasks"

[output]
default_format = "md"
exclude_merges = true
include_body = false
include_diff_stats = true
max_commits = 100

[repository]
default_branch = "main"
tag_pattern = "v[0-9]*"
url = "https://github.com/username/repository"

[templates]
commit_format = "- {message} ({hash} by {author})"
date_format = "%Y-%m-%d"
footer = """

---
Generated by [RCGen](https://github.com/yoursname/rcgen)"""
header = """
# Changelog

All notable changes to this project will be documented in this file.
"""

• url: Repository URL for reference
• default_branch: Default branch (default: "main")
• tag_pattern: Regex pattern to detect version tags

• default_format: Default output format [md, json, text]
• include_body: Include commit body
• include_diff_stats: Include diff statistics
• exclude_merges: Exclude merge commits
• max_commits: Maximum limit of commits processed

• exclude_authors: List of authors to exclude
• exclude_patterns: Regex pattern to exclude commits
• include_patterns: Regex pattern to include commits (if empty, all commits are included)

• enabled: Enable grouping
• groups: List of commit groups with patterns and descriptions

• header: Header template for output
• footer: Footer template for output
• commit_format: Format string for each commit (supports placeholders: {message}, {hash}, {author}, {date})
• date_format: Date format for output

# Changelog

## 2024-01-15

- feat: Add user authentication system (`abc123` by John Doe) - 3 files changed (+120 -10)
  > Implement JWT-based authentication
  > Add login and registration endpoints
- fix: Resolve memory leak in database connection (`def456` by Jane Smith) - 1 file changed (+5 -15)

## Statistics

- Total commits: 150
- Total authors: 5
- Files changed: 42
- Insertions: +5402
- Deletions: -1234
- Bus factor: 2.5

### Top Contributors

1. John Doe <john@example.com> - 42 commits (+1200 -234)
2. Jane Smith <jane@example.com> - 38 commits (+890 -456)
3. Bob Johnson <bob@example.com> - 25 commits (+650 -123)

{
  "commits": [
    {
      "hash": "abc123def456",
      "short_hash": "abc123",
      "author": {
        "name": "John Doe",
        "email": "john@example.com",
        "commits_count": 42
      },
      "date": "2024-01-15T10:30:00+00:00",
      "message": "feat: Add user authentication system\n\nImplement JWT-based authentication",
      "summary": "feat: Add user authentication system",
      "body": "Implement JWT-based authentication",
      "files_changed": ["src/auth.rs", "src/models.rs"],
      "insertions": 120,
      "deletions": 10,
      "is_merge": false,
      "tags": ["v1.2.0"],
      "branches": ["main"],
      "commit_type": "feat",
      "scope": null
    }
  ],
  "stats": {
    "total_commits": 150,
    "total_authors": 5,
    "first_commit": "2023-01-01T00:00:00+00:00",
    "last_commit": "2024-01-15T10:30:00+00:00",
    "period_days": 379,
    "commits_per_day": 0.4,
    "authors": [".."],
    "files_changed": 42,
    "total_insertions": 5402,
    "total_deletions": 1234,
    "bus_factor": 2.5,
    "commit_types": {
      "feats": 45,
      "fix": 32,
      "docs": 18,
      "refactor": 25,
      "chore": 30
    },
    "most_active_day": "2024-01-10",
    "most_active_hour": 14
  },
  "generated_at": "2024-01-15T12:00:00Z"
}

CHANGELOG
==============================================================================
2024-01-15
----------
* feat: Add user authentication system [abc123] - John Doe (2024-01-15) | 3 files, +120/-10
> Implement JWT-based authentication
* fix: Resolve memory leak in database connection [def456] - Jane Smith (2024-01-15) | 1 file, +5/-15
STATISTICS
------------------------------------------------------------------------------
Total commits: 150
Total authors: 5
Files changed: 42
Total changes: +5402 / -1234
Bus factor: 2.