From 8951fbdb1b3d0e464c9f623d520e5829e110e9b6 Mon Sep 17 00:00:00 2001
From: Matt Provost <provomat@amazon.com>
Date: Sat, 24 Jun 2023 02:06:30 +0000
Subject: [PATCH] Add changelog generation script

Signed-off-by: Matt Provost <provomat@amazon.com>
---
 changelogs/fragments/1234.yml |  5 +++
 changelogs/fragments/5678.yml |  5 +++
 package.json                  |  3 +-
 scripts/generate_changelog.js |  7 +++
 src/dev/generate_changelog.ts | 83 +++++++++++++++++++++++++++++++++++
 5 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 changelogs/fragments/1234.yml
 create mode 100644 changelogs/fragments/5678.yml
 create mode 100644 scripts/generate_changelog.js
 create mode 100644 src/dev/generate_changelog.ts

diff --git a/changelogs/fragments/1234.yml b/changelogs/fragments/1234.yml
new file mode 100644
index 00000000000..f482e3d2e5a
--- /dev/null
+++ b/changelogs/fragments/1234.yml
@@ -0,0 +1,5 @@
+fix:
+  - This is a sample fixed
+
+feat:
+  - Introduces a new feature
diff --git a/changelogs/fragments/5678.yml b/changelogs/fragments/5678.yml
new file mode 100644
index 00000000000..444c31887f7
--- /dev/null
+++ b/changelogs/fragments/5678.yml
@@ -0,0 +1,5 @@
+feat:
+  - Introduces a new feature pt 2
+
+doc:
+  - Document a feature
diff --git a/package.json b/package.json
index dbe2e7302ff..e355d4af440 100644
--- a/package.json
+++ b/package.json
@@ -74,7 +74,8 @@
     "docs:acceptApiChanges": "scripts/use_node --max-old-space-size=6144 scripts/check_published_api_changes.js --accept",
     "osd:bootstrap": "scripts/use_node scripts/build_ts_refs && scripts/use_node scripts/register_git_hook",
     "spec_to_console": "scripts/use_node scripts/spec_to_console",
-    "pkg-version": "scripts/use_node -e \"console.log(require('./package.json').version)\""
+    "pkg-version": "scripts/use_node -e \"console.log(require('./package.json').version)\"",
+    "changelog:generate": "scripts/use_node scripts/generate_changelog"
   },
   "repository": {
     "type": "git",
diff --git a/scripts/generate_changelog.js b/scripts/generate_changelog.js
new file mode 100644
index 00000000000..efcdf9b0dc9
--- /dev/null
+++ b/scripts/generate_changelog.js
@@ -0,0 +1,7 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+require('../src/setup_node_env');
+require('../src/dev/generate_changelog');
diff --git a/src/dev/generate_changelog.ts b/src/dev/generate_changelog.ts
new file mode 100644
index 00000000000..3b006a8bb74
--- /dev/null
+++ b/src/dev/generate_changelog.ts
@@ -0,0 +1,83 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { resolve } from 'path';
+import { readFileSync, writeFileSync, readdirSync } from 'fs';
+import { load as loadYaml } from 'js-yaml';
+import { version as pkgVersion } from '../../package.json';
+
+const CHANGELOG_HEADER = `# CHANGELOG
+
+Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)`;
+
+const SECTION_MAPPING = {
+  breaking: '💥 Breaking Changes',
+  deprecate: 'Deprecations',
+  feat: '📈 Features/Enhancements',
+  fix: '🐛 Bug Fixes',
+  infra: '🚞 Infrastructure',
+  doc: '📝 Documentation',
+  chore: '🛠 Maintenance',
+  refactor: '🪛 Refactoring',
+  test: '🔩 Tests',
+};
+
+const SECTION_KEYS = Object.keys(SECTION_MAPPING);
+type SectionKey = keyof typeof SECTION_MAPPING;
+type Changelog = Record<SectionKey, string[]>;
+
+const sections: Partial<Changelog> = {};
+
+const fragmentDirPath = resolve(__dirname, '..', '..', 'changelogs', 'fragments');
+const fragmentPaths = readdirSync(fragmentDirPath).filter(
+  (path) => path.endsWith('.yml') || path.endsWith('.yaml')
+);
+
+for (const fragmentFilename of fragmentPaths) {
+  const fragmentPath = resolve(fragmentDirPath, fragmentFilename);
+  const fragmentContents = readFileSync(fragmentPath, { encoding: 'utf-8' });
+  const fragmentYaml = loadYaml(fragmentContents) as Changelog;
+
+  const prNumber = fragmentFilename.split('.').slice(0, -1).join('.');
+
+  for (const [sectionKey, entries] of Object.entries(fragmentYaml)) {
+    if (!SECTION_KEYS.includes(sectionKey)) {
+      // eslint-disable-next-line no-console
+      console.warn(`Unknown section ${sectionKey}. Ignoring`);
+      continue;
+    }
+
+    const section = sections[sectionKey as SectionKey] || (sections[sectionKey as SectionKey] = []);
+    section.push(
+      ...entries.map(
+        (entry) =>
+          `${entry} ([#${prNumber}](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/${prNumber}))`
+      )
+    );
+  }
+}
+
+const changelogSections = [];
+
+for (const [sectionKey, entries] of Object.entries(sections)) {
+  if (!entries) {
+    continue;
+  }
+
+  const sectionName = SECTION_MAPPING[sectionKey as SectionKey];
+
+  changelogSections.push(`### ${sectionName}
+
+${entries.map((entry) => ` - ${entry}`).join('\n')}`);
+}
+
+const changelog = `${CHANGELOG_HEADER}
+
+## [${pkgVersion}](https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/${pkgVersion})
+
+${changelogSections.join('\n\n')}
+`;
+
+writeFileSync(resolve(__dirname, '..', '..', 'CHANGELOG.md'), changelog);