feat: Add mirror and mirror-token inputs for custom Python distribution sources

Users who need custom CPython builds (internal mirrors, GHES-hosted forks, special build configurations, compliance builds, air-gapped runners) could not previously point setup-python at anything other than actions/python-versions. Adds two new inputs: - `mirror`: base URL hosting versions-manifest.json and the Python distributions it references. Defaults to the existing https://raw.githubusercontent.com/actions/python-versions/main. - `mirror-token`: optional token used to authenticate requests to the mirror. If `mirror` is a raw.githubusercontent.com/{owner}/{repo}/{branch} URL, the manifest is fetched via the GitHub REST API (authenticated rate limit applies); otherwise the action falls back to a direct GET of {mirror}/versions-manifest.json. Token interaction ----------------- `token` is never forwarded to arbitrary hosts. Auth resolution is per-URL: 1. if mirror-token is set, use mirror-token 2. else if token is set AND the target host is github.com, *.github.com, or *.githubusercontent.com, use token 3. else send no auth Cases: Default (no inputs set) mirror = default raw.githubusercontent.com URL, mirror-token empty, token = github.token. → manifest API call and tarball downloads use `token`. Identical to prior behavior. Custom raw.githubusercontent.com mirror (e.g. personal fork) mirror-token empty, token = github.token. → manifest API call and tarball downloads use `token` (target hosts are GitHub-owned). Custom non-GitHub mirror, no mirror-token mirror-token empty, token = github.token. → manifest fetched via direct URL (no auth attached), tarball downloads use no auth. `token` is NOT forwarded to the custom host — this is the leak-prevention case. Custom non-GitHub mirror with mirror-token mirror-token set, token may be set. → manifest fetch and tarball downloads use `mirror-token`. Custom GitHub mirror with both tokens set mirror-token wins. Used for both the manifest API call and tarball downloads.
2026-04-06 09:56:54 +00:00 · 2026-04-06 00:59:40 +02:00 · 2026-04-06 00:59:40 +02:00 · 8b57351c0f
commit 8b57351c0f
parent 28f2168f4d
7 changed files with 441 additions and 41 deletions
--- a/.github/workflows/test-python.yml
+++ b/.github/workflows/test-python.yml
@ -58,6 +58,26 @@ jobs:
      - name: Run simple code
        run: python -c 'import math; print(math.factorial(5))'

+  setup-versions-via-mirror-input:
+    name: 'Setup via explicit mirror input: ${{ matrix.os }}'
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: setup-python with explicit mirror
+        uses: ./
+        with:
+          python-version: 3.12
+          mirror: https://raw.githubusercontent.com/actions/python-versions/main
+
+      - name: Run simple code
+        run: python -c 'import sys; print(sys.version)'
+
  setup-versions-from-file:
    name: Setup ${{ matrix.python }} ${{ matrix.os }} version file
    runs-on: ${{ matrix.os }}
--- a/tests/install-python.test.ts
+++ b/tests/install-python.test.ts
@ -1,16 +1,29 @@
 import {
  getManifest,
  getManifestFromRepo,
-  getManifestFromURL
+  getManifestFromURL,
+  installCpythonFromRelease
 } from '../src/install-python';
 import * as httpm from '@actions/http-client';
 import * as tc from '@actions/tool-cache';

 jest.mock('@actions/http-client');
-jest.mock('@actions/tool-cache');
 jest.mock('@actions/tool-cache', () => ({
-  getManifestFromRepo: jest.fn()
+  getManifestFromRepo: jest.fn(),
+  downloadTool: jest.fn(),
+  extractTar: jest.fn(),
+  extractZip: jest.fn(),
+  HTTPError: class HTTPError extends Error {}
 }));
+jest.mock('@actions/exec', () => ({
+  exec: jest.fn().mockResolvedValue(0)
+}));
+jest.mock('../src/utils', () => ({
+  ...jest.requireActual('../src/utils'),
+  IS_WINDOWS: false,
+  IS_LINUX: false
+}));
+
 const mockManifest = [
  {
    version: '1.0.0',
@ -26,11 +39,27 @@ const mockManifest = [
  }
 ];

-describe('getManifest', () => {
-  beforeEach(() => {
-    jest.resetAllMocks();
-  });
+function setInputs(values: Record<string, string | undefined>) {
+  for (const key of ['TOKEN', 'MIRROR', 'MIRROR-TOKEN']) {
+    delete process.env[`INPUT_${key}`];
+  }
+  for (const [k, v] of Object.entries(values)) {
+    if (v !== undefined) {
+      process.env[`INPUT_${k.toUpperCase()}`] = v;
+    }
+  }
+}

+beforeEach(() => {
+  jest.resetAllMocks();
+  setInputs({});
+});
+
+afterAll(() => {
+  setInputs({});
+});
+
+describe('getManifest', () => {
  it('should return manifest from repo', async () => {
    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
    const manifest = await getManifest();
@ -50,10 +79,82 @@ describe('getManifest', () => {
 });

 describe('getManifestFromRepo', () => {
-  it('should return manifest from repo', async () => {
+  it('default mirror calls getManifestFromRepo with actions/python-versions@main and token', async () => {
+    setInputs({token: 'TKN'});
    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
-    const manifest = await getManifestFromRepo();
-    expect(manifest).toEqual(mockManifest);
+    await getManifestFromRepo();
+    expect(tc.getManifestFromRepo).toHaveBeenCalledWith(
+      'actions',
+      'python-versions',
+      'token TKN',
+      'main'
+    );
+  });
+
+  it('custom raw mirror extracts owner/repo/branch and passes token', async () => {
+    setInputs({
+      token: 'TKN',
+      mirror: 'https://raw.githubusercontent.com/foo/bar/dev'
+    });
+    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
+    await getManifestFromRepo();
+    expect(tc.getManifestFromRepo).toHaveBeenCalledWith(
+      'foo',
+      'bar',
+      'token TKN',
+      'dev'
+    );
+  });
+
+  it('custom non-GitHub mirror throws (caller falls through to URL fetch)', () => {
+    setInputs({mirror: 'https://mirror.example/py'});
+    expect(() => getManifestFromRepo()).toThrow(/not a GitHub repo URL/);
+  });
+
+  it('mirror-token wins over token for the api.github.com call (getManifestFromRepo)', async () => {
+    setInputs({
+      token: 'TKN',
+      'mirror-token': 'MTOK',
+      mirror: 'https://raw.githubusercontent.com/foo/bar/main'
+    });
+    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
+    await getManifestFromRepo();
+    expect(tc.getManifestFromRepo).toHaveBeenCalledWith(
+      'foo',
+      'bar',
+      'token MTOK',
+      'main'
+    );
+  });
+
+  it('token is used when mirror-token is empty (getManifestFromRepo)', async () => {
+    setInputs({
+      token: 'TKN',
+      mirror: 'https://raw.githubusercontent.com/foo/bar/main'
+    });
+    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
+    await getManifestFromRepo();
+    expect(tc.getManifestFromRepo).toHaveBeenCalledWith(
+      'foo',
+      'bar',
+      'token TKN',
+      'main'
+    );
+  });
+
+  it('trailing slashes in mirror URL are stripped', async () => {
+    setInputs({
+      token: 'TKN',
+      mirror: 'https://raw.githubusercontent.com/foo/bar/main/'
+    });
+    (tc.getManifestFromRepo as jest.Mock).mockResolvedValue(mockManifest);
+    await getManifestFromRepo();
+    expect(tc.getManifestFromRepo).toHaveBeenCalledWith(
+      'foo',
+      'bar',
+      'token TKN',
+      'main'
+    );
  });
 });

@ -74,4 +175,116 @@ describe('getManifestFromURL', () => {
      'Unable to get manifest from'
    );
  });
+
+  it('fetches from {mirror}/versions-manifest.json (no auth header attached)', async () => {
+    setInputs({token: 'TKN', mirror: 'https://mirror.example/py'});
+    (httpm.HttpClient.prototype.getJson as jest.Mock).mockResolvedValue({
+      result: mockManifest
+    });
+    await getManifestFromURL();
+    expect(httpm.HttpClient.prototype.getJson).toHaveBeenCalledWith(
+      'https://mirror.example/py/versions-manifest.json'
+    );
+  });
+});
+
+describe('mirror URL validation', () => {
+  it('throws on invalid URL when used', () => {
+    setInputs({mirror: 'not a url'});
+    expect(() => getManifestFromRepo()).toThrow(/Invalid 'mirror' URL/);
+  });
+});
+
+describe('installCpythonFromRelease auth gating', () => {
+  const makeRelease = (downloadUrl: string) =>
+    ({
+      version: '3.12.0',
+      stable: true,
+      release_url: '',
+      files: [
+        {
+          filename: 'python-3.12.0-linux-x64.tar.gz',
+          platform: 'linux',
+          platform_version: '',
+          arch: 'x64',
+          download_url: downloadUrl
+        }
+      ]
+    }) as any;
+
+  function stubInstallExtract() {
+    (tc.downloadTool as jest.Mock).mockResolvedValue('/tmp/py.tgz');
+    (tc.extractTar as jest.Mock).mockResolvedValue('/tmp/extracted');
+  }
+
+  it('forwards token to github.com download URLs', async () => {
+    setInputs({token: 'TKN'});
+    stubInstallExtract();
+    await installCpythonFromRelease(
+      makeRelease(
+        'https://github.com/actions/python-versions/releases/download/3.12.0-x/python-3.12.0-linux-x64.tar.gz'
+      )
+    );
+    expect(tc.downloadTool).toHaveBeenCalledWith(
+      expect.any(String),
+      undefined,
+      'token TKN'
+    );
+  });
+
+  it('forwards token to api.github.com URLs', async () => {
+    setInputs({token: 'TKN'});
+    stubInstallExtract();
+    await installCpythonFromRelease(
+      makeRelease('https://api.github.com/repos/x/y/tarball/main')
+    );
+    expect(tc.downloadTool).toHaveBeenCalledWith(
+      expect.any(String),
+      undefined,
+      'token TKN'
+    );
+  });
+
+  it('forwards token to objects.githubusercontent.com download URLs', async () => {
+    setInputs({token: 'TKN'});
+    stubInstallExtract();
+    await installCpythonFromRelease(
+      makeRelease('https://objects.githubusercontent.com/x/python.tar.gz')
+    );
+    expect(tc.downloadTool).toHaveBeenCalledWith(
+      expect.any(String),
+      undefined,
+      'token TKN'
+    );
+  });
+
+  it('does NOT forward token to non-GitHub download URLs', async () => {
+    setInputs({token: 'TKN'});
+    stubInstallExtract();
+    await installCpythonFromRelease(
+      makeRelease('https://cdn.example/py.tar.gz')
+    );
+    expect(tc.downloadTool).toHaveBeenCalledWith(
+      expect.any(String),
+      undefined,
+      undefined
+    );
+  });
+
+  it('forwards mirror-token to non-GitHub download URLs', async () => {
+    setInputs({
+      token: 'TKN',
+      'mirror-token': 'MTOK',
+      mirror: 'https://cdn.example'
+    });
+    stubInstallExtract();
+    await installCpythonFromRelease(
+      makeRelease('https://cdn.example/py.tar.gz')
+    );
+    expect(tc.downloadTool).toHaveBeenCalledWith(
+      expect.any(String),
+      undefined,
+      'token MTOK'
+    );
+  });
 });
--- a/action.yml
+++ b/action.yml
@ -16,8 +16,14 @@ inputs:
    description: "Set this option if you want the action to check for the latest available version that satisfies the version spec."
    default: false
  token:
-    description: "The token used to authenticate when fetching Python distributions from https://github.com/actions/python-versions. When running this action on github.com, the default value is sufficient. When running on GHES, you can pass a personal access token for github.com if you are experiencing rate limiting."
+    description: "The token used to authenticate when fetching Python distributions from https://github.com/actions/python-versions. When running this action on github.com, the default value is sufficient. When running on GHES, you can pass a personal access token for github.com if you are experiencing rate limiting. When 'mirror-token' is set, it takes precedence over this input."
    default: ${{ github.server_url == 'https://github.com' && github.token || '' }}
+  mirror:
+    description: "Base URL for downloading Python distributions. Defaults to https://raw.githubusercontent.com/actions/python-versions/main. See docs/advanced-usage.md for details."
+    default: "https://raw.githubusercontent.com/actions/python-versions/main"
+  mirror-token:
+    description: "Token used to authenticate requests to 'mirror'. Takes precedence over 'token'."
+    required: false
  cache-dependency-path:
    description: "Used to specify the path to dependency files. Supports wildcards or a list of file names for caching multiple dependencies."
  update-environment:
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@ -83007,7 +83007,7 @@ async function useCpythonVersion(version, architecture, updateEnvironment, check
        if (freethreaded) {
            msg.push(`Free threaded versions are only available for Python 3.13.0 and later.`);
        }
-        msg.push(`The list of all available versions can be found here: ${installer.MANIFEST_URL}`);
+        msg.push(`The list of all available versions can be found here: ${installer.getManifestUrl()}`);
        throw new Error(msg.join(os.EOL));
    }
    const _binDir = binDir(installDir);
@ -83617,7 +83617,7 @@ var __importStar = (this && this.__importStar) || (function () {
    };
 })();
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.MANIFEST_URL = void 0;
+exports.getManifestUrl = getManifestUrl;
 exports.findReleaseFromManifest = findReleaseFromManifest;
 exports.getManifest = getManifest;
 exports.getManifestFromRepo = getManifestFromRepo;
@ -83629,12 +83629,56 @@ const tc = __importStar(__nccwpck_require__(33472));
 const exec = __importStar(__nccwpck_require__(95236));
 const httpm = __importStar(__nccwpck_require__(54844));
 const utils_1 = __nccwpck_require__(71798);
-const TOKEN = core.getInput('token');
-const AUTH = !TOKEN ? undefined : `token ${TOKEN}`;
-const MANIFEST_REPO_OWNER = 'actions';
-const MANIFEST_REPO_NAME = 'python-versions';
-const MANIFEST_REPO_BRANCH = 'main';
-exports.MANIFEST_URL = `https://raw.githubusercontent.com/${MANIFEST_REPO_OWNER}/${MANIFEST_REPO_NAME}/${MANIFEST_REPO_BRANCH}/versions-manifest.json`;
+const DEFAULT_REPO_OWNER = 'actions';
+const DEFAULT_REPO_NAME = 'python-versions';
+const DEFAULT_REPO_BRANCH = 'main';
+const DEFAULT_MIRROR = `https://raw.githubusercontent.com/${DEFAULT_REPO_OWNER}/${DEFAULT_REPO_NAME}/${DEFAULT_REPO_BRANCH}`;
+// Matches https://raw.githubusercontent.com/{owner}/{repo}/{branch}
+const REPO_COORDS_RE = /^https:\/\/raw\.githubusercontent\.com\/([^/]+)\/([^/]+)\/([^/]+)\/?$/;
+function getToken() {
+    return core.getInput('token');
+}
+function getMirrorToken() {
+    return core.getInput('mirror-token');
+}
+function getMirror() {
+    const raw = (core.getInput('mirror') || DEFAULT_MIRROR)
+        .trim()
+        .replace(/\/+$/, '');
+    try {
+        new URL(raw);
+    }
+    catch {
+        throw new Error(`Invalid 'mirror' URL: "${raw}"`);
+    }
+    return raw;
+}
+function getManifestUrl() {
+    return `${getMirror()}/versions-manifest.json`;
+}
+function resolveRepoCoords() {
+    const m = REPO_COORDS_RE.exec(getMirror());
+    return m ? { owner: m[1], repo: m[2], branch: m[3] } : null;
+}
+function authForUrl(url) {
+    const mirrorToken = getMirrorToken();
+    if (mirrorToken)
+        return `token ${mirrorToken}`;
+    let host;
+    try {
+        host = new URL(url).host;
+    }
+    catch {
+        return undefined;
+    }
+    const token = getToken();
+    if (token &&
+        (host === 'github.com' ||
+            host.endsWith('.github.com') ||
+            host.endsWith('.githubusercontent.com')))
+        return `token ${token}`;
+    return undefined;
+}
 async function findReleaseFromManifest(semanticVersionSpec, architecture, manifest) {
    if (!manifest) {
        manifest = await getManifest();
@ -83675,15 +83719,28 @@ async function getManifest() {
    return await getManifestFromURL();
 }
 function getManifestFromRepo() {
-    core.debug(`Getting manifest from ${MANIFEST_REPO_OWNER}/${MANIFEST_REPO_NAME}@${MANIFEST_REPO_BRANCH}`);
-    return tc.getManifestFromRepo(MANIFEST_REPO_OWNER, MANIFEST_REPO_NAME, AUTH, MANIFEST_REPO_BRANCH);
+    const coords = resolveRepoCoords();
+    if (!coords) {
+        throw new Error(`Mirror "${getMirror()}" is not a GitHub repo URL; falling back to raw URL fetch.`);
+    }
+    core.debug(`Getting manifest from ${coords.owner}/${coords.repo}@${coords.branch}`);
+    // api.github.com is a GitHub-owned URL. Prefer MIRROR_TOKEN (the user provided token), fall back to TOKEN.
+    const token = getToken();
+    const mirrorToken = getMirrorToken();
+    const auth = !mirrorToken
+        ? !token
+            ? undefined
+            : `token ${token}`
+        : `token ${mirrorToken}`;
+    return tc.getManifestFromRepo(coords.owner, coords.repo, auth, coords.branch);
 }
 async function getManifestFromURL() {
    core.debug('Falling back to fetching the manifest using raw URL.');
+    const manifestUrl = getManifestUrl();
    const http = new httpm.HttpClient('tool-cache');
-    const response = await http.getJson(exports.MANIFEST_URL);
+    const response = await http.getJson(manifestUrl);
    if (!response.result) {
-        throw new Error(`Unable to get manifest from ${exports.MANIFEST_URL}`);
+        throw new Error(`Unable to get manifest from ${manifestUrl}`);
    }
    return response.result;
 }
@ -83720,7 +83777,7 @@ async function installCpythonFromRelease(release) {
    let pythonPath = '';
    try {
        const fileName = (0, utils_1.getDownloadFileName)(downloadUrl);
-        pythonPath = await tc.downloadTool(downloadUrl, fileName, AUTH);
+        pythonPath = await tc.downloadTool(downloadUrl, fileName, authForUrl(downloadUrl));
        core.info('Extract downloaded archive');
        let pythonExtractedFolder;
        if (utils_1.IS_WINDOWS) {
--- a/docs/advanced-usage.md
+++ b/docs/advanced-usage.md
@ -525,6 +525,41 @@ Such a requirement on side-effect could be because you don't want your composite

 >**Note:** Python versions used in this action are generated in the [python-versions](https://github.com/actions/python-versions) repository. For macOS and Ubuntu images, python versions are built from the source code. For Windows, the python-versions repository uses installation executable. For more information please refer to the [python-versions](https://github.com/actions/python-versions) repository.

+#### Using a custom mirror
+
+The `mirror` input lets you point `setup-python` at a different location for CPython distributions — a personal fork of `actions/python-versions`, an internal mirror, or any server that hosts a `versions-manifest.json` at its root plus the tarballs referenced by that manifest. Default: `https://raw.githubusercontent.com/actions/python-versions/main`.
+
+The manifest is resolved as follows:
+
+- If `mirror` matches `https://raw.githubusercontent.com/{owner}/{repo}/{branch}`, the manifest is fetched via the GitHub REST API (giving you the 5000/hr authenticated rate limit when a token is present).
+- Otherwise, the action fetches `{mirror}/versions-manifest.json` via a direct HTTP GET.
+
+Authentication:
+
+- `token` is forwarded **only** to `github.com` and hosts under `*.github.com` or `*.githubusercontent.com`. It is never sent to a custom mirror.
+- `mirror-token` takes precedence over `token`: if `mirror-token` is set it is used for every authenticated request (manifest fetch and tarball downloads).
+- If `mirror-token` is empty, `token` is used when the target URL is GitHub-owned.
+- If neither applies, requests are anonymous.
+
+Point at a personal fork of `actions/python-versions` (uses the default `token`, fetched via the GitHub API):
+
+```yaml
+- uses: actions/setup-python@v6
+  with:
+    python-version: '3.12'
+    mirror: https://raw.githubusercontent.com/my-org/python-versions/main
+```
+
+Point at an internal mirror with its own credential:
+
+```yaml
+- uses: actions/setup-python@v6
+  with:
+    python-version: '3.12'
+    mirror: https://python-mirror.internal.example
+    mirror-token: ${{ secrets.PYTHON_MIRROR_TOKEN }}
+```
+
 ### PyPy

 `setup-python` is able to configure **PyPy** from two sources:
--- a/src/find-python.ts
+++ b/src/find-python.ts
@ -137,7 +137,7 @@ export async function useCpythonVersion(
      );
    }
    msg.push(
-      `The list of all available versions can be found here: ${installer.MANIFEST_URL}`
+      `The list of all available versions can be found here: ${installer.getManifestUrl()}`
    );
    throw new Error(msg.join(os.EOL));
  }
--- a/src/install-python.ts
+++ b/src/install-python.ts
@ -7,12 +7,67 @@ import {ExecOptions} from '@actions/exec/lib/interfaces';
 import {IS_WINDOWS, IS_LINUX, getDownloadFileName} from './utils';
 import {IToolRelease} from '@actions/tool-cache';

-const TOKEN = core.getInput('token');
-const AUTH = !TOKEN ? undefined : `token ${TOKEN}`;
-const MANIFEST_REPO_OWNER = 'actions';
-const MANIFEST_REPO_NAME = 'python-versions';
-const MANIFEST_REPO_BRANCH = 'main';
-export const MANIFEST_URL = `https://raw.githubusercontent.com/${MANIFEST_REPO_OWNER}/${MANIFEST_REPO_NAME}/${MANIFEST_REPO_BRANCH}/versions-manifest.json`;
+const DEFAULT_REPO_OWNER = 'actions';
+const DEFAULT_REPO_NAME = 'python-versions';
+const DEFAULT_REPO_BRANCH = 'main';
+const DEFAULT_MIRROR = `https://raw.githubusercontent.com/${DEFAULT_REPO_OWNER}/${DEFAULT_REPO_NAME}/${DEFAULT_REPO_BRANCH}`;
+
+// Matches https://raw.githubusercontent.com/{owner}/{repo}/{branch}
+const REPO_COORDS_RE =
+  /^https:\/\/raw\.githubusercontent\.com\/([^/]+)\/([^/]+)\/([^/]+)\/?$/;
+
+function getToken(): string {
+  return core.getInput('token');
+}
+
+function getMirrorToken(): string {
+  return core.getInput('mirror-token');
+}
+
+function getMirror(): string {
+  const raw = (core.getInput('mirror') || DEFAULT_MIRROR)
+    .trim()
+    .replace(/\/+$/, '');
+  try {
+    new URL(raw);
+  } catch {
+    throw new Error(`Invalid 'mirror' URL: "${raw}"`);
+  }
+  return raw;
+}
+
+export function getManifestUrl(): string {
+  return `${getMirror()}/versions-manifest.json`;
+}
+
+function resolveRepoCoords(): {
+  owner: string;
+  repo: string;
+  branch: string;
+} | null {
+  const m = REPO_COORDS_RE.exec(getMirror());
+  return m ? {owner: m[1], repo: m[2], branch: m[3]} : null;
+}
+
+function authForUrl(url: string): string | undefined {
+  const mirrorToken = getMirrorToken();
+  if (mirrorToken) return `token ${mirrorToken}`;
+  let host: string;
+  try {
+    host = new URL(url).host;
+  } catch {
+    return undefined;
+  }
+  const token = getToken();
+  if (
+    token &&
+    (host === 'github.com' ||
+      host.endsWith('.github.com') ||
+      host.endsWith('.githubusercontent.com'))
+  )
+    return `token ${token}`;
+  return undefined;
+}

 export async function findReleaseFromManifest(
  semanticVersionSpec: string,
@ -73,24 +128,34 @@ export async function getManifest(): Promise<tc.IToolRelease[]> {
 }

 export function getManifestFromRepo(): Promise<tc.IToolRelease[]> {
+  const coords = resolveRepoCoords();
+  if (!coords) {
+    throw new Error(
+      `Mirror "${getMirror()}" is not a GitHub repo URL; falling back to raw URL fetch.`
+    );
+  }
  core.debug(
-    `Getting manifest from ${MANIFEST_REPO_OWNER}/${MANIFEST_REPO_NAME}@${MANIFEST_REPO_BRANCH}`
-  );
-  return tc.getManifestFromRepo(
-    MANIFEST_REPO_OWNER,
-    MANIFEST_REPO_NAME,
-    AUTH,
-    MANIFEST_REPO_BRANCH
+    `Getting manifest from ${coords.owner}/${coords.repo}@${coords.branch}`
  );
+  // api.github.com is a GitHub-owned URL. Prefer MIRROR_TOKEN (the user provided token), fall back to TOKEN.
+  const token = getToken();
+  const mirrorToken = getMirrorToken();
+  const auth = !mirrorToken
+    ? !token
+      ? undefined
+      : `token ${token}`
+    : `token ${mirrorToken}`;
+  return tc.getManifestFromRepo(coords.owner, coords.repo, auth, coords.branch);
 }

 export async function getManifestFromURL(): Promise<tc.IToolRelease[]> {
  core.debug('Falling back to fetching the manifest using raw URL.');

+  const manifestUrl = getManifestUrl();
  const http: httpm.HttpClient = new httpm.HttpClient('tool-cache');
-  const response = await http.getJson<tc.IToolRelease[]>(MANIFEST_URL);
+  const response = await http.getJson<tc.IToolRelease[]>(manifestUrl);
  if (!response.result) {
-    throw new Error(`Unable to get manifest from ${MANIFEST_URL}`);
+    throw new Error(`Unable to get manifest from ${manifestUrl}`);
  }
  return response.result;
 }
@ -130,7 +195,11 @@ export async function installCpythonFromRelease(release: tc.IToolRelease) {
  let pythonPath = '';
  try {
    const fileName = getDownloadFileName(downloadUrl);
-    pythonPath = await tc.downloadTool(downloadUrl, fileName, AUTH);
+    pythonPath = await tc.downloadTool(
+      downloadUrl,
+      fileName,
+      authForUrl(downloadUrl)
+    );
    core.info('Extract downloaded archive');
    let pythonExtractedFolder;
    if (IS_WINDOWS) {