Add experimatal code to terminate runners

Author: npalm

modules/runners/lambdas/scale-runners/src/scale-runners/runners.ts

@@ -56,6 +56,16 @@ export interface RunnerInputParameters {
   orgName?: string;
 }
 
+export async function terminateRunner(runner: RunnerInfo): Promise<void> {
+  const ec2 = new EC2();
+  const result = await ec2
+    .terminateInstances({
+      InstanceIds: [runner.instanceId],
+    })
+    .promise();
+  console.debug('Runner terminated.' + result.TerminatingInstances);
+}
+
 export async function createRunner(runnerParameters: RunnerInputParameters): Promise<void> {
   const launchTemplateName = process.env.LAUNCH_TEMPLATE_NAME as string;
   const launchTemplateVersion = process.env.LAUNCH_TEMPLATE_VERSION as string;

modules/runners/lambdas/scale-runners/src/scale-runners/scale-down.ts

@@ -1,5 +1,123 @@
-import { EC2 } from 'aws-sdk';
+import { createAppAuth } from '@octokit/auth-app';
+import { Octokit } from '@octokit/rest';
+import { AppAuth } from '@octokit/auth-app/dist-types/types';
+import { listRunners, terminateRunner, RunnerInfo } from './runners';
+import { createGithubAppAuth, createInstallationClient } from './scale-up';
+
+// function createGithubAppAuth(installationId: number | undefined): AppAuth {
+//   const privateKey = Buffer.from(process.env.GITHUB_APP_KEY_BASE64 as string, 'base64').toString();
+//   const appId: number = parseInt(process.env.GITHUB_APP_ID as string);
+//   const clientId = process.env.GITHUB_APP_CLIENT_ID as string;
+//   const clientSecret = process.env.GITHUB_APP_CLIENT_SECRET as string;
+
+//   return createAppAuth({
+//     id: appId,
+//     privateKey: privateKey,
+//     installationId: installationId,
+//     clientId: clientId,
+//     clientSecret: clientSecret,
+//   });
+// }
+
+// async function createInstallationClient(githubAppAuth: AppAuth): Promise<Octokit> {
+//   const auth = await githubAppAuth({ type: 'installation' });
+//   return new Octokit({ auth: auth.token });
+// }
+
+// specific to scale down
+async function createAppClient(githubAppAuth: AppAuth): Promise<Octokit> {
+  const auth = await githubAppAuth({ type: 'app' });
+  return new Octokit({ auth: auth.token });
+}
+
+interface Repo {
+  isOrg: boolean;
+  repoName: string;
+  repoOwner: string;
+}
+
+function getRepo(runner: RunnerInfo): Repo {
+  if (runner.repo) {
+    return {
+      repoOwner: runner.repo?.split('/')[0] as string,
+      repoName: runner.repo?.split('/')[1] as string,
+      isOrg: false,
+    };
+  } else {
+    return {
+      repoOwner: runner.org as string,
+      repoName: '',
+      isOrg: true,
+    };
+  }
+}
+
+async function createGitHubClientForRunner(runner: RunnerInfo): Promise<Octokit> {
+  const githubClient = await createAppClient(createGithubAppAuth(undefined));
+  const repo = getRepo(runner);
+
+  const repoInstallationId = repo.isOrg
+    ? (
+        await githubClient.apps.getOrgInstallation({
+          org: repo.repoOwner,
+        })
+      ).data.id
+    : (
+        await githubClient.apps.getRepoInstallation({
+          owner: repo.repoOwner,
+          repo: repo.repoName,
+        })
+      ).data.id;
+
+  return createInstallationClient(createGithubAppAuth(repoInstallationId));
+}
 
 export async function scaleDown(): Promise<void> {
-  console.info('Not implemented yet');
+  const environment = process.env.ENVIRONMENT as string;
+  const runners = await listRunners({
+    environment: environment,
+  });
+
+  if (runners?.length === 0) {
+    console.debug(`No active runners found for environment: '${environment}'`);
+    return;
+  }
+
+  runners.forEach(async (r) => {
+    const githubAppClient = await createGitHubClientForRunner(r);
+
+    const repo = getRepo(r);
+    const registered = await githubAppClient.actions.listSelfHostedRunnersForRepo({
+      owner: repo.repoOwner,
+      repo: repo.repoName,
+    });
+
+    console.log(registered.data.runners);
+    registered.data.runners.forEach(async (a: any) => {
+      const runnerName = a.name as string;
+      if (runnerName === r.instanceId) {
+        console.log(r.instanceId);
+        try {
+          const result = repo.isOrg
+            ? await githubAppClient.actions.deleteSelfHostedRunnerFromOrg({ runner_id: a.id, org: repo.repoOwner })
+            : await githubAppClient.actions.deleteSelfHostedRunnerFromRepo({
+                runner_id: a.id,
+                owner: repo.repoOwner,
+                repo: repo.repoName,
+              });
+          if (result?.status == 204) {
+            terminateRunner(r);
+            console.info(
+              `AWS runner instance '${r.instanceId}' is terminated and GitHub runner '${runnerName}' is de-registered.`,
+            );
+          }
+          console.info(
+            `AWS runner instance '${r.instanceId}' is terminated and GitHub runner '${runnerName}' is de-registered.`,
+          );
+        } catch (e) {
+          console.debug(`Runner '${runnerName}' cannot be de-registered, most likely the runner is active.`);
+        }
+      }
+    });
+  });
 }

modules/runners/lambdas/scale-runners/src/scale-runners/scale-up.ts

@@ -12,7 +12,7 @@ export interface ActionRequestMessage {
   installationId: number;
 }
 
-function createGithubAppAuth(installationId: number): AppAuth {
+export function createGithubAppAuth(installationId: number | undefined): AppAuth {
   const privateKey = Buffer.from(process.env.GITHUB_APP_KEY_BASE64 as string, 'base64').toString();
   const appId: number = parseInt(process.env.GITHUB_APP_ID as string);
   const clientId = process.env.GITHUB_APP_CLIENT_ID as string;
@@ -27,7 +27,7 @@ function createGithubAppAuth(installationId: number): AppAuth {
   });
 }
 
-async function createInstallationClient(githubAppAuth: AppAuth): Promise<Octokit> {
+export async function createInstallationClient(githubAppAuth: AppAuth): Promise<Octokit> {
   const auth = await githubAppAuth({ type: 'installation' });
   return new Octokit({ auth: auth.token });
 }

modules/runners/policies/lambda-scale-down.json

@@ -6,7 +6,7 @@
       "Action": [
         "ec2:DescribeInstances*",
         "ec2:DescribeTags",
-        "ec2:CreateTags",
+        "ec2:DeleteTags",
         "ec2:TerminateInstances"
       ],
       "Resource": ["*"]