Chore: Add changelog github action (#90183)

* add changelog github action

* tabs vs spaces

* better disable release, even in draft

* add codeowners

.github/CODEOWNERS

@@ -720,6 +720,8 @@ embed.go @grafana/grafana-as-code
 /.github/workflows/run-scenes-e2e.yml @grafana/dashboards-squad
 /.github/workflows/go_lint.yml @grafana/grafana-backend-services-squad
 /.github/workflows/trivy-scan.yml @grafana/grafana-backend-services-squad
+/.github/workflows/changelog.yml @zserge
+/.github/workflows/actions/changelog @zserge
 
 # Generated files not requiring owner approval
 /packages/grafana-data/src/types/featureToggles.gen.ts @grafanabot

.github/workflows/actions/changelog/action.yml

@@ -0,0 +1,22 @@
+name: Changelog generator
+description: Generates and publishes a changelog for the given release version
+inputs:
+  version:
+    description: Version number
+    required: true
+  prev_version:
+    description: Previous version number
+    required: false
+  token:
+    description: GitHub token with read/write access to all necessary repositories
+    required: true
+  output_file:
+    description: A file to store resulting changelog markdown
+    required: false
+outputs:
+  changelog:
+    description: Changelog contents between the two given versions in Markdown format
+runs:
+  using: 'node20'
+  main: 'index.js'
+  

.github/workflows/actions/changelog/index.js

@@ -0,0 +1,317 @@
+import { appendFileSync, writeFileSync } from 'fs';
+import { exec as execCallback } from 'node:child_process';
+import { promisify } from 'node:util';
+
+//
+// Github Action core utils: logging (notice + debug log levels), must escape
+// newlines and percent signs
+//
+const escapeData = (s) => s.replace(/%/g, '%25').replace(/\r/g, '%0D').replace(/\n/g, '%0A');
+const LOG = (msg) => console.log(`::notice::${escapeData(msg)}`);
+
+//
+// Semver utils: parse, compare, sort etc (using official regexp)
+// https://regex101.com/r/Ly7O1x/3/
+//
+const semverRegExp =
+  /^v?(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$/;
+
+const semverParse = (tag) => {
+  const m = tag.match(semverRegExp);
+  if (!m) {
+    return;
+  }
+  const [_, major, minor, patch, prerelease] = m;
+  return [+major, +minor, +patch, prerelease, tag];
+};
+
+// semverCompare takes two parsed semver tags and comparest them more or less
+// according to the semver specs
+const semverCompare = (a, b) => {
+  for (let i = 0; i < 3; i++) {
+    if (a[i] !== b[i]) {
+      return a[i] < b[i] ? 1 : -1;
+    }
+  }
+  if (a[3] !== b[3]) {
+    return a[3] < b[3] ? 1 : -1;
+  }
+  return 0;
+};
+
+// Using `git tag -l` output find the tag (version) that goes semantically
+// right before the given version. This might not work correctly with some
+// pre-release versions, which is why it's possible to pass previous version
+// into this action explicitly to avoid this step.
+const getPreviousVersion = async (version) => {
+  const exec = promisify(execCallback);
+  const { stdout } = await exec('git tag -l');
+  const prev = stdout
+    .split('\n')
+    .map(semverParse)
+    .filter((tag) => tag)
+    .sort(semverCompare)
+    .find((tag) => semverCompare(tag, semverParse(version)) > 0);
+  return prev;
+};
+
+// A helper for Github GraphQL API endpoint
+const graphql = async (token, query, variables) => {
+  const { env } = process;
+  const results = await fetch('https://api.github.com/graphql', {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      Authorization: `Bearer ${token}`,
+    },
+    body: JSON.stringify({ query, variables }),
+  });
+  const { data } = await results.json();
+  return data;
+};
+
+// Using Github GraphQL API find the timestamp for the given tag/commit hash.
+// This is required for PR listing, because Github API only takes date/time as
+// a "since" parameter while listing. Currently there is no way to provide two
+// "commitish" items and get a list of PRs in between them.
+const getCommitishDate = async (name, owner, target) => {
+  const result = await graphql(
+    token,
+    `
+      query getCommitDate($owner: String!, $name: String!, $target: String!) {
+        repository(owner: $owner, name: $name) {
+          object(expression: $target) {
+            ... on Commit {
+              committedDate
+            }
+          }
+        }
+      }
+    `,
+    { name, owner, target }
+  );
+  return result.repository.object.committedDate;
+};
+
+// Using Github GraphQL API get a list of PRs between the two "commitish" items.
+// This resoves the "since" item's timestamp first and iterates over all PRs
+// till "target" using naïve pagination.
+const getHistory = async (name, owner, target, since) => {
+  const sinceDate = await getCommitishDate(name, owner, since);
+  LOG(`Fetching ${owner}/${name} PRs since ${since} (${sinceDate}) till ${target}`);
+  const query = `
+  query findCommitsWithAssociatedPullRequests(
+    $name: String!
+    $owner: String!
+    $target: String!
+    $sinceDate: GitTimestamp
+    $cursor: String
+  ) {
+    repository(name: $name, owner: $owner) {
+      object(expression: $target) {
+        ... on Commit {
+          history(first: 50, since: $sinceDate, after: $cursor) {
+            totalCount
+            pageInfo {
+              hasNextPage
+              endCursor
+            }
+            nodes {
+              id
+              associatedPullRequests(first: 1) {
+                nodes {
+                  title
+                  number
+                  labels(first: 10) {
+                    nodes {
+                      name
+                    }
+                  }
+                  commits(first: 1) {
+                    nodes {
+                      commit {
+                        author {
+                          user {
+                            login
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }`;
+
+  let cursor;
+  let nodes = [];
+  for (;;) {
+    const result = await graphql(token, query, {
+      name,
+      owner,
+      target,
+      sinceDate,
+      cursor,
+    });
+    LOG(`GraphQL: ${JSON.stringify(result)}`);
+    nodes = [...nodes, ...result.repository.object.history.nodes];
+    const { hasNextPage, endCursor } = result.repository.object.history.pageInfo;
+    if (!hasNextPage) {
+      break;
+    }
+    cursor = endCursor;
+  }
+  return nodes;
+};
+
+// The main function for this action: given two "commitish" items it gets a
+// list of PRs between them and filters/groups the PRs by category (bugfix,
+// feature, deprecation, breaking change and plugin fixes/enhancements).
+//
+// PR grouping relies on Github labels only, not on the PR contents.
+const getChangeLogItems = async (name, owner, from, to) => {
+  // check if a node contains a certain label
+  const hasLabel = ({ labels }, label) => labels.nodes.some(({ name }) => name === label);
+  // get all the PRs between the two "commitish" items
+  const history = await getHistory(name, owner, to, from);
+
+  const items = history.flatMap((node) => {
+    // discard PRs without a "changelog" label
+    const changes = node.associatedPullRequests.nodes.filter((PR) => hasLabel(PR, 'add to changelog'));
+    if (changes.length === 0) {
+      return [];
+    }
+    const item = changes[0];
+    const { number, url, labels } = item;
+    const title = item.title.replace(/^\[[^\]]+\]:?\s*/, '');
+    // for changelog PRs try to find a suitable category.
+    // Note that we can not detect "deprecation notices" like that
+    // as there is no suitable label yet.
+    const isBug = /fix/i.test(title) || hasLabel({ labels }, 'type/bug');
+    const isBreaking = hasLabel({ labels }, 'breaking change');
+    const isPlugin =
+      hasLabel({ labels }, 'area/grafana/ui') ||
+      hasLabel({ labels }, 'area/grafana/toolkit') ||
+      hasLabel({ labels }, 'area/grafana/runtime');
+    const author = item.commits.nodes[0].commit.author.user.login;
+    return {
+      repo: name,
+      number,
+      title,
+      author,
+      isBug,
+      isPlugin,
+      isBreaking,
+    };
+  });
+  return items;
+};
+
+// ======================================================
+//                 GENERATE CHANGELOG
+// ======================================================
+
+LOG(`Changelog action started`);
+const version = process.argv[2] || process.env.INPUT_VERSION;
+LOG(`Target version: ${version}`);
+const prevVersion = process.argv[3] || process.env.INPUT_PREV_VERSION || (await getPreviousVersion(version));
+LOG(`Previous version: ${prevVersion}`);
+const token = process.env.GITHUB_TOKEN || process.env.INPUT_TOKEN;
+
+if (!token) {
+  throw 'GITHUB_TOKEN is not set and "token" input is empty';
+}
+
+// Get all changelog items from Grafana OSS
+const oss = await getChangeLogItems('grafana', 'grafana', prevVersion, version);
+// Get all changelog items from Grafana Enterprise
+const entr = await getChangeLogItems('grafana-enterprise', 'grafana', prevVersion, version);
+
+LOG(`Found OSS PRs: ${oss.length}`);
+LOG(`Found Enterprise PRs: ${entr.length}`);
+
+// Sort PRs and categorise them into sections
+const changelog = [...oss, ...entr]
+  .sort((a, b) => (a.title < b.title ? -1 : 1))
+  .reduce(
+    (changelog, item) => {
+      if (item.isPlugin) {
+        changelog.plugins.push(item);
+      } else if (item.isBug) {
+        changelog.bugfixes.push(item);
+      } else if (item.isBreaking) {
+        changelog.breaking.push(item);
+      } else {
+        changelog.features.push(item);
+      }
+      return changelog;
+    },
+    {
+      version,
+      breaking: [],
+      plugins: [],
+      bugfixes: [],
+      features: [],
+      // looks like JS doesn't have a nicer way to format date as YYYY-MM-DD
+      releaseDate: new Date().toISOString().split('T')[0],
+    }
+  );
+
+// Convert PR numbers to Github links
+const pullRequestLink = (n) => `[#${n}](https://github.com/grafana/grafana/pull/${n})`;
+// Convert Github user IDs to Github links
+const userLink = (u) => `[@${u}](https://github.com/${u})`;
+
+// Now that we have a changelog - we can render some markdown as an output
+const markdown = (changelog) => {
+  // This convers a list of changelog items into a markdown section with a list of titles/links
+  const section = (title, items) =>
+    items.length === 0
+      ? ''
+      : `### ${title}
+
+${items
+  .map(
+    (item) =>
+      `- ${item.title.replace(/^([^:]*:)/gm, '**$1**')} ${
+        item.repo === 'grafana-enterprise'
+          ? '(Enterprise)'
+          : `${pullRequestLink(item.number)}, ${userLink(item.author)}`
+      }`
+  )
+  .join('\n')}
+  `;
+
+  // Render all present sections for the given changelog
+  return `# ${changelog.version} (${changelog.releaseDate})
+
+${section('Breaking changes', changelog.breaking)}
+${section('Bug fixes', changelog.bugfixes)}
+${section('Plugin development fixes & changes', changelog.plugins)}
+${section('Features and enhancements', changelog.features)}
+`;
+};
+
+const md = markdown(changelog);
+
+// Print changelog, mostly for debugging
+LOG(`Resulting markdown: ${md}`);
+
+// Save changelog as an output for this action
+if (process.env.GITHUB_OUTPUT) {
+  LOG(`Output to ${process.env.GITHUB_OUTPUT}`);
+  appendFileSync(process.env.GITHUB_OUTPUT, `changelog<<EOF\n${escapeData(md)}\nEOF`);
+} else {
+  LOG('GITHUB_OUTPUT is not set');
+}
+
+// Save changelog as an output file (if requested)
+if (process.env.INPUT_OUTPUT_FILE) {
+  LOG(`Output to ${process.env.INPUT_OUTPUT_FILE}`);
+  writeFileSync(process.env.INPUT_OUTPUT_FILE, md);
+}
+

.github/workflows/changelog.yml

@@ -0,0 +1,43 @@
+name: Generate changelog
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        required: true
+        description: 'Target release version (git tag)'
+      prev_version:
+        required: true
+        description: 'Previous release version (git tag)'
+jobs:
+  main:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: "Generate token"
+        id: generate_token
+        uses: tibdex/github-app-token@b62528385c34dbc9f38e5f4225ac829252d1ea92
+        with:
+          app_id: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_ID }}
+          private_key: ${{ secrets.GRAFANA_DELIVERY_BOT_APP_PEM }}
+      - name: "Checkout Grafana repo"
+        uses: "actions/checkout@v4"
+        with:
+          sparse-checkout: .github/workflows
+          fetch-depth: 0
+          fetch-tags: true
+      - name: "Generate changelog"
+        id: changelog
+        uses: ./.github/workflows/actions/changelog
+        with:
+          token: ${{ steps.generate_token.outputs.token }}
+          version: ${{ inputs.version }}
+          prev_version: ${{ inputs.prev_version }}
+          output_file: _changelog.md
+      - name: "Draft Github Release"
+        env:
+          GH_TOKEN: ${{ steps.generate_token.outputs.token }}
+        run: |
+          cat _changelog.md
+          # skip for now
+          # gh release create --draft ${{ inputs.version }} --notes-file _changelog.md