Add GitHub security advisory alerts workflow

.github/workflows/github-security-advisory-alerts.yml

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+name: GitHub Security Advisory Alerts
+
+on:
+  schedule:
+    # Nightly at 09:00 UTC
+    - cron: "0 9 * * *"
+  workflow_dispatch: {}
+
+permissions: {}
+
+concurrency:
+  group: github-security-advisory-alerts
+  cancel-in-progress: true
+
+jobs:
+  send-alert:
+    environment: ai-bots
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: read
+    steps:
+      - name: Create GitHub App token
+        id: app-token
+        uses: actions/create-github-app-token@v2
+        with:
+          app-id: ${{ vars.KEPPO_GITHUB_APP_ID }}
+          private-key: ${{ secrets.KEPPO_GITHUB_APP_PRIVATE_KEY }}
+          # No permission-* scoping: repository_advisories is not yet
+          # supported by create-github-app-token, so we inherit all
+          # permissions from the App installation.
+
+      - name: Checkout repository
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 1
+          persist-credentials: false
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
+      - name: Send advisory alert email
+        env:
+          GITHUB_API_URL: ${{ github.api_url }}
+          GITHUB_TOKEN: ${{ steps.app-token.outputs.token }}
+          GITHUB_REPOSITORY: ${{ github.repository }}
+          SECURITY_ADVISORY_ALERT_EMAILS: ${{ vars.SECURITY_ADVISORY_ALERT_EMAILS }}
+          GITHUB_RUN_ID: ${{ github.run_id }}
+          GITHUB_SERVER_URL: ${{ github.server_url }}
+          MAILGUN_API_KEY: ${{ secrets.MAILGUN_API_KEY }}
+          MAILGUN_DOMAIN: ${{ vars.MAILGUN_DOMAIN }}
+          MAILGUN_FROM_EMAIL: ${{ vars.MAILGUN_FROM_EMAIL }}
+        run: node scripts/github-security-advisory-alert.mjs

scripts/github-security-advisory-alert.mjs

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+import fs from "node:fs/promises";
+
+const GITHUB_API_VERSION = "2022-11-28";
+const MAILGUN_API_BASE_URL = "https://api.mailgun.net/v3";
+const ADVISORY_STATES = ["triage", "draft"];
+
+const requireEnv = (name) => {
+  const value = process.env[name]?.trim();
+  if (!value) {
+    throw new Error(`Missing required environment variable: ${name}`);
+  }
+  return value;
+};
+
+const parseRecipients = (value) => {
+  const seen = new Set();
+  const recipients = [];
+
+  for (const entry of value.split(",")) {
+    const email = entry.trim();
+    if (!email || seen.has(email)) {
+      continue;
+    }
+    seen.add(email);
+    recipients.push(email);
+  }
+
+  if (recipients.length === 0) {
+    throw new Error(
+      "SECURITY_ADVISORY_ALERT_EMAILS must contain at least one email address",
+    );
+  }
+
+  return recipients;
+};
+
+const getNextPageUrl = (linkHeader) => {
+  if (!linkHeader) {
+    return null;
+  }
+
+  for (const part of linkHeader.split(",")) {
+    const match = part.match(/<([^>]+)>;\s*rel="next"/);
+    if (match) {
+      return match[1];
+    }
+  }
+
+  return null;
+};
+
+const readResponseBody = async (response) => {
+  const text = await response.text();
+  return text.trim().slice(0, 500);
+};
+
+const fetchAdvisoryCount = async ({ apiBaseUrl, repository, token, state }) => {
+  let nextUrl = new URL(
+    `${apiBaseUrl}/repos/${repository}/security-advisories`,
+  );
+  nextUrl.searchParams.set("state", state);
+  nextUrl.searchParams.set("per_page", "100");
+
+  let total = 0;
+
+  while (nextUrl) {
+    const response = await fetch(nextUrl, {
+      headers: {
+        Authorization: `Bearer ${token}`,
+        Accept: "application/vnd.github+json",
+        "X-GitHub-Api-Version": GITHUB_API_VERSION,
+      },
+    });
+
+    if (!response.ok) {
+      const body = await readResponseBody(response);
+      throw new Error(
+        `Failed to list ${state} security advisories: ${response.status} ${body}`,
+      );
+    }
+
+    const advisories = await response.json();
+    if (!Array.isArray(advisories)) {
+      throw new Error(`Unexpected ${state} advisories response shape`);
+    }
+
+    total += advisories.length;
+
+    const nextPage = getNextPageUrl(response.headers.get("link"));
+    nextUrl = nextPage ? new URL(nextPage) : null;
+  }
+
+  return total;
+};
+
+const escapeHtml = (value) =>
+  value
+    .replaceAll("&", "&amp;")
+    .replaceAll("<", "&lt;")
+    .replaceAll(">", "&gt;")
+    .replaceAll('"', "&quot;")
+    .replaceAll("'", "&#39;");
+
+const appendStepSummary = async (summary) => {
+  const path = process.env.GITHUB_STEP_SUMMARY;
+  if (!path) {
+    return;
+  }
+  await fs.appendFile(path, `${summary}\n`, "utf8");
+};
+
+const sendMailgunEmail = async ({
+  apiKey,
+  domain,
+  from,
+  recipients,
+  subject,
+  text,
+  html,
+}) => {
+  const response = await fetch(`${MAILGUN_API_BASE_URL}/${domain}/messages`, {
+    method: "POST",
+    headers: {
+      Authorization: `Basic ${Buffer.from(`api:${apiKey}`).toString("base64")}`,
+      "Content-Type": "application/x-www-form-urlencoded",
+    },
+    body: new URLSearchParams({
+      from,
+      to: recipients.join(","),
+      subject,
+      text,
+      html,
+    }),
+  });
+
+  if (!response.ok) {
+    const body = await readResponseBody(response);
+    throw new Error(
+      `Failed to send advisory email: ${response.status} ${body}`,
+    );
+  }
+};
+
+const main = async () => {
+  const token = requireEnv("GITHUB_TOKEN");
+  const repository = requireEnv("GITHUB_REPOSITORY");
+  const mailgunApiKey = requireEnv("MAILGUN_API_KEY");
+  const mailgunDomain = requireEnv("MAILGUN_DOMAIN");
+  const fromEmail = requireEnv("MAILGUN_FROM_EMAIL");
+  const recipients = parseRecipients(
+    requireEnv("SECURITY_ADVISORY_ALERT_EMAILS"),
+  );
+  const githubApiBaseUrl =
+    process.env.GITHUB_API_URL?.trim() || "https://api.github.com";
+  const githubServerUrl =
+    process.env.GITHUB_SERVER_URL?.trim() || "https://github.com";
+  const runId = process.env.GITHUB_RUN_ID?.trim();
+
+  const advisoryCounts = Object.fromEntries(
+    await Promise.all(
+      ADVISORY_STATES.map(async (state) => [
+        state,
+        await fetchAdvisoryCount({
+          repository,
+          token,
+          state,
+          apiBaseUrl: githubApiBaseUrl,
+        }),
+      ]),
+    ),
+  );
+  const totalCount = ADVISORY_STATES.reduce(
+    (sum, state) => sum + advisoryCounts[state],
+    0,
+  );
+
+  const triageUrl = `${githubServerUrl}/${repository}/security/advisories?state=triage`;
+  const draftUrl = `${githubServerUrl}/${repository}/security/advisories?state=draft`;
+  const runUrl = runId
+    ? `${githubServerUrl}/${repository}/actions/runs/${runId}`
+    : null;
+
+  await appendStepSummary(`Repository: \`${repository}\``);
+  await appendStepSummary(`Triage advisories: ${advisoryCounts.triage}`);
+  await appendStepSummary(`Draft advisories: ${advisoryCounts.draft}`);
+  await appendStepSummary(
+    `Total open advisories in triage/draft: ${totalCount}`,
+  );
+
+  if (totalCount === 0) {
+    console.log(
+      `No open triage or draft security advisories found for ${repository}.`,
+    );
+    return;
+  }
+
+  const subject = `[ALERT] You have ${totalCount} GitHub security advisories open for ${repository}`;
+  const textLines = [
+    `Repository: ${repository}`,
+    "",
+    `Open GitHub security advisories in triage/draft: ${totalCount}`,
+    `Triage: ${advisoryCounts.triage}`,
+    `Draft: ${advisoryCounts.draft}`,
+    "",
+    "Review advisories:",
+    `Triage: ${triageUrl}`,
+    `Draft: ${draftUrl}`,
+  ];
+
+  if (runUrl) {
+    textLines.push("", `Workflow run: ${runUrl}`);
+  }
+
+  const html = `
+<!doctype html>
+<html>
+  <body style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;color:#111827;line-height:1.5;">
+    <h2 style="margin-bottom:12px;">GitHub security advisory alert</h2>
+    <p style="margin:0 0 12px;"><strong>Repository:</strong> ${escapeHtml(repository)}</p>
+    <p style="margin:0 0 12px;">
+      Open GitHub security advisories in <code>triage</code>/<code>draft</code>: <strong>${totalCount}</strong>
+    </p>
+    <ul style="margin:0 0 16px;padding-left:20px;">
+      <li>Triage: ${advisoryCounts.triage}</li>
+      <li>Draft: ${advisoryCounts.draft}</li>
+    </ul>
+    <p style="margin:0 0 8px;"><a href="${escapeHtml(triageUrl)}">Review triage advisories</a></p>
+    <p style="margin:0 0 8px;"><a href="${escapeHtml(draftUrl)}">Review draft advisories</a></p>
+    ${runUrl ? `<p style="margin:16px 0 0;">Workflow run: <a href="${escapeHtml(runUrl)}">${escapeHtml(runUrl)}</a></p>` : ""}
+  </body>
+</html>
+  `.trim();
+
+  await sendMailgunEmail({
+    apiKey: mailgunApiKey,
+    domain: mailgunDomain,
+    from: fromEmail,
+    recipients,
+    subject,
+    text: textLines.join("\n"),
+    html,
+  });
+
+  console.log(
+    `Sent GitHub security advisory alert for ${repository} to ${recipients.length} recipient(s).`,
+  );
+};
+
+await main();