generate installation token for each play run

utils/generate-installation-token.ts

@@ -0,0 +1,196 @@
+import { createSign } from "node:crypto";
+import { config } from "dotenv";
+
+config();
+
+interface GitHubAppConfig {
+  appId: string;
+  privateKey: string;
+  repoOwner: string;
+  repoName: string;
+}
+
+interface Installation {
+  id: number;
+  account: {
+    login: string;
+    type: string;
+  };
+}
+
+interface Repository {
+  owner: {
+    login: string;
+  };
+  name: string;
+}
+
+interface InstallationTokenResponse {
+  token: string;
+  expires_at: string;
+}
+
+interface RepositoriesResponse {
+  repositories: Repository[];
+}
+
+const validateConfig = (config: GitHubAppConfig): void => {
+  const { appId, privateKey, repoOwner, repoName } = config;
+
+  if (!appId) {
+    throw new Error("GITHUB_APP_ID environment variable is required");
+  }
+
+  if (!privateKey) {
+    throw new Error("GITHUB_PRIVATE_KEY environment variable is required");
+  }
+
+  if (!repoOwner || !repoName) {
+    throw new Error("REPO_OWNER and REPO_NAME environment variables are required");
+  }
+
+  if (!privateKey.includes("BEGIN") || !privateKey.includes("END")) {
+    throw new Error("GITHUB_PRIVATE_KEY must be in PEM format");
+  }
+};
+
+const base64UrlEncode = (str: string): string => {
+  return Buffer.from(str)
+    .toString("base64")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g, "");
+};
+
+const generateJWT = (appId: string, privateKey: string): string => {
+  const now = Math.floor(Date.now() / 1000);
+  const payload = {
+    iat: now - 60,
+    exp: now + 5 * 60,
+    iss: appId,
+  };
+
+  const header = {
+    alg: "RS256",
+    typ: "JWT",
+  };
+
+  const encodedHeader = base64UrlEncode(JSON.stringify(header));
+  const encodedPayload = base64UrlEncode(JSON.stringify(payload));
+  const signaturePart = `${encodedHeader}.${encodedPayload}`;
+
+  const signature = createSign("RSA-SHA256")
+    .update(signaturePart)
+    .sign(privateKey, "base64")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g, "");
+
+  return `${signaturePart}.${signature}`;
+};
+
+const githubRequest = async <T>(
+  path: string,
+  options: {
+    method?: string;
+    headers?: Record<string, string>;
+    body?: string;
+  } = {}
+): Promise<T> => {
+  const { method = "GET", headers = {}, body } = options;
+
+  const url = `https://api.github.com${path}`;
+  const requestHeaders = {
+    Accept: "application/vnd.github.v3+json",
+    "User-Agent": "Pullfrog-Installation-Token-Generator/1.0",
+    ...headers,
+  };
+
+  const response = await fetch(url, {
+    method,
+    headers: requestHeaders,
+    ...(body && { body }),
+  });
+
+  if (!response.ok) {
+    const errorText = await response.text();
+    throw new Error(
+      `GitHub API request failed: ${response.status} ${response.statusText}\n${errorText}`
+    );
+  }
+
+  return response.json() as T;
+};
+
+const checkRepositoryAccess = async (token: string, repoOwner: string, repoName: string): Promise<boolean> => {
+  try {
+    const response = await githubRequest<RepositoriesResponse>(
+      "/installation/repositories",
+      {
+        headers: { Authorization: `token ${token}` },
+      }
+    );
+
+    return response.repositories.some(
+      (repo) => repo.owner.login === repoOwner && repo.name === repoName
+    );
+  } catch {
+    return false;
+  }
+};
+
+const createInstallationToken = async (jwt: string, installationId: number): Promise<string> => {
+  const response = await githubRequest<InstallationTokenResponse>(
+    `/app/installations/${installationId}/access_tokens`,
+    {
+      method: "POST",
+      headers: { Authorization: `Bearer ${jwt}` },
+    }
+  );
+
+  return response.token;
+};
+
+const findInstallationId = async (jwt: string, repoOwner: string, repoName: string): Promise<number> => {
+  const installations = await githubRequest<Installation[]>("/app/installations", {
+    headers: { Authorization: `Bearer ${jwt}` },
+  });
+
+  for (const installation of installations) {
+    try {
+      const tempToken = await createInstallationToken(jwt, installation.id);
+      const hasAccess = await checkRepositoryAccess(tempToken, repoOwner, repoName);
+
+      if (hasAccess) {
+        return installation.id;
+      }
+    } catch {
+      // Installation doesn't have access to repository
+    }
+  }
+
+  throw new Error(
+    `No installation found with access to ${repoOwner}/${repoName}. ` +
+      "Ensure the GitHub App is installed on the target repository."
+  );
+};
+
+export const generateInstallationToken = async (
+  repoOwner?: string,
+  repoName?: string
+): Promise<string> => {
+  const config: GitHubAppConfig = {
+    appId: process.env.GITHUB_APP_ID!,
+    privateKey: process.env.GITHUB_PRIVATE_KEY?.replace(/\\n/g, "\n")!,
+    repoOwner: repoOwner || process.env.REPO_OWNER || "pullfrogai",
+    repoName: repoName || process.env.REPO_NAME || "scratch",
+  };
+
+  validateConfig(config);
+
+  const jwt = generateJWT(config.appId, config.privateKey);
+  const installationId = await findInstallationId(jwt, config.repoOwner, config.repoName);
+  const token = await createInstallationToken(jwt, installationId);
+
+  return token;
+};