Changelog.js

changelog.js

#!/usr/bin/env node

// TODO(vojta): pre-commit hook for validating messages
// TODO(vojta): report errors, currently Q silence everything which really sucks

'use strict';

var child = require('child_process');
var fs = require('fs');
var util = require('util');
var q = require('qq');

var GIT_LOG_CMD = 'git log --grep="%s" -E --format=%s %s..HEAD';
var GIT_TAG_CMD = 'git describe --tags --abbrev=0';

var HEADER_TPL = '<a name="%s"></a>\n# %s (%s)\n\n';
var LINK_ISSUE = '[#%s](https://github.com/deployd/deployd/issues/%s)';
var LINK_COMMIT = '[%s](https://github.com/deployd/deployd/commit/%s)';

var EMPTY_COMPONENT = '$$';


var warn = function() {
  console.log('WARNING:', util.format.apply(null, arguments));
};


var parseRawCommit = function(raw) {
  if (!raw) return null;

  var lines = raw.split('\n');
  var msg = {}, match;

  msg.hash = lines.shift();
  msg.subject = lines.shift();
  msg.closes = [];
  msg.breaks = [];

  lines.forEach(function(line) {
    match = line.match(/(?:Closes|Fixes)\s#(\d+)/);
    if (match) msg.closes.push(parseInt(match[1]));
  });

  match = raw.match(/BREAKING CHANGE:([\s\S]*)/);
  if (match) {
    msg.breaking = match[1];
  }


  msg.body = lines.join('\n');
  match = msg.subject.match(/^(.*)\((.*)\)\:\s(.*)$/);

  if (!match || !match[1] || !match[3]) {
    warn('Incorrect message: %s %s', msg.hash, msg.subject);
    return null;
  }

  msg.type = match[1];
  msg.component = match[2];
  msg.subject = match[3];

  return msg;
};


var linkToIssue = function(issue) {
  return util.format(LINK_ISSUE, issue, issue);
};


var linkToCommit = function(hash) {
  return util.format(LINK_COMMIT, hash.substr(0, 8), hash);
};


var currentDate = function() {
  var now = new Date();
  var pad = function(i) {
    return ('0' + i).substr(-2);
  };

  return util.format('%d-%s-%s', now.getFullYear(), pad(now.getMonth() + 1), pad(now.getDate()));
};


var printSection = function(stream, title, section, printCommitLinks) {
  printCommitLinks = printCommitLinks === undefined ? true : printCommitLinks;
  var components = Object.getOwnPropertyNames(section).sort();

  if (!components.length) return;

  stream.write(util.format('\n## %s\n\n', title));

  components.forEach(function(name) {
    var prefix = '-';
    var nested = section[name].length > 1;

    if (name !== EMPTY_COMPONENT) {
      if (nested) {
        stream.write(util.format('- **%s:**\n', name));
        prefix = '  -';
      } else {
        prefix = util.format('- **%s:**', name);
      }
    }

    section[name].forEach(function(commit) {
      if (printCommitLinks) {
        stream.write(util.format('%s %s\n  (%s', prefix, commit.subject, linkToCommit(commit.hash)));
        if (commit.closes.length) {
          stream.write(',\n   ' + commit.closes.map(linkToIssue).join(', '));
        }
        stream.write(')\n');
      } else {
        stream.write(util.format('%s %s\n', prefix, commit.subject));
      }
    });
  });

  stream.write('\n');
};


var readGitLog = function(grep, from) {
  var deferred = q.defer();

  // TODO(vojta): if it's slow, use spawn and stream it instead
  child.exec(util.format(GIT_LOG_CMD, grep, '%H%n%s%n%b%n==END==', from), function(code, stdout, stderr) {
    var commits = [];

    stdout.split('\n==END==\n').forEach(function(rawCommit) {
      var commit = parseRawCommit(rawCommit);
      if (commit) commits.push(commit);
    });

    deferred.resolve(commits);
  });

  return deferred.promise;
};


var writeChangelog = function(stream, commits, version) {
  var sections = {
    fix: {},
    feature: {},
    perf: {},
    breaks: {}
  };

  sections.breaks[EMPTY_COMPONENT] = [];

  commits.forEach(function(commit) {
    var section = sections[commit.type];
    var component = commit.component || EMPTY_COMPONENT;

    if (section) {
      section[component] = section[component] || [];
      section[component].push(commit);
    }

    if (commit.breaking) {
      sections.breaks[component] = sections.breaks[component] || [];
      sections.breaks[component].push({
        subject: util.format("due to %s,\n %s", linkToCommit(commit.hash), commit.breaking),
        hash: commit.hash,
        closes: []
      });
    }
  });

  stream.write(util.format(HEADER_TPL, version, version, currentDate()));
  printSection(stream, 'Bug Fixes', sections.fix);
  printSection(stream, 'Features', sections.feature);
  printSection(stream, 'Performance Improvements', sections.perf);
  printSection(stream, 'Breaking Changes', sections.breaks, false);
};


var getPreviousTag = function() {
  var deferred = q.defer();
  child.exec(GIT_TAG_CMD, function(code, stdout, stderr) {
    if (code) deferred.reject('Cannot get the previous tag.');
    else deferred.resolve(stdout.replace('\n', ''));
  });
  return deferred.promise;
};


var generate = function(version, file) {

  getPreviousTag().then(function(tag) {
    console.log('Reading git log since', tag);
    readGitLog('^fix|^feature|^perf|BREAKING', tag).then(function(commits) {
      console.log('Parsed', commits.length, 'commits');
      console.log('Generating changelog to', file || 'stdout', '(', version, ')');
      writeChangelog(file ? fs.createWriteStream(file) : process.stdout, commits, version);
    });
  });
};


// publish for testing
exports.parseRawCommit = parseRawCommit;
exports.printSection = printSection;

// hacky start if not run by jasmine :-D
if (process.argv.join('').indexOf('jasmine-node') === -1) {
  generate(process.argv[2], process.argv[3]);
}

usage.md

Changelog generator

This script will generate a changelog for the commits since latest tag.

Usage

1. Copy the script in the folder of your app.
2. git fetch origin to get the latest tags
3. node changelog.js v0.8.3 to generate changelog in the terminal
4. Copy/paste the code in your HISTORY.md/CHANGELOG.md