[bazel] Setup remote cache settings on bootstrap (elastic#121445)

.bazelrc.common

@@ -132,6 +132,9 @@ coverage --instrument_test_targets
 # Metadata settings
 build --workspace_status_command="node ./src/dev/bazel_workspace_status.js"
 
+# Load remote cache settings, if they exist
+try-import %workspace%/.bazelrc.cache
+
 # Load any settings specific to the current user.
 # .bazelrc.user should appear in .gitignore so that settings are not shared with team members
 # This needs to be last statement in this

.gitignore

@@ -87,8 +87,9 @@ report.asciidoc
 /bazel
 /bazel-*
 .bazelrc.user
+.bazelrc.cache
 
 elastic-agent-*
 fleet-server-*
 elastic-agent.yml
-fleet-server.yml
+fleet-server.yml

packages/kbn-pm/src/commands/bootstrap.ts

@@ -23,6 +23,7 @@ import {
   runBazel,
   yarnIntegrityFileExists,
 } from '../utils/bazel';
+import { setupRemoteCache } from '../utils/bazel/setup_remote_cache';
 
 export const BootstrapCommand: ICommand = {
   description: 'Install dependencies and crosslink projects',
@@ -55,6 +56,9 @@ export const BootstrapCommand: ICommand = {
     // Install bazel machinery tools if needed
     await installBazelTools(rootPath);
 
+    // Setup remote cache settings in .bazelrc.cache if needed
+    await setupRemoteCache(rootPath);
+
     // Bootstrap process for Bazel packages
     // Bazel is now managing dependencies so yarn install
     // will happen as part of this

packages/kbn-pm/src/utils/bazel/setup_remote_cache.ts

@@ -0,0 +1,92 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+import dedent from 'dedent';
+import { existsSync, writeFileSync } from 'fs';
+import { resolve } from 'path';
+import { spawn } from '../child_process';
+import { log } from '../log';
+
+async function isVaultAvailable() {
+  try {
+    await spawn('vault', ['--version'], { stdio: 'pipe' });
+
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function isElasticCommitter() {
+  try {
+    const { stdout: email } = await spawn('git', ['config', 'user.email'], {
+      stdio: 'pipe',
+    });
+
+    return email.trim().endsWith('@elastic.co');
+  } catch {
+    return false;
+  }
+}
+
+export async function setupRemoteCache(repoRootPath: string) {
+  // The remote cache is only for Elastic employees working locally (CI cache settings are handled elsewhere)
+  if (process.env.CI || !(await isElasticCommitter())) {
+    return;
+  }
+
+  log.debug(`[bazel_tools] setting up remote cache settings if necessary`);
+
+  const settingsPath = resolve(repoRootPath, '.bazelrc.cache');
+
+  if (existsSync(settingsPath)) {
+    log.debug(`[bazel_tools] remote cache settings already exist, skipping`);
+    return;
+  }
+
+  if (!(await isVaultAvailable())) {
+    log.info('[bazel_tools] vault is not available, unable to setup remote cache settings.');
+    log.info('[bazel_tools] building packages will work, but will be slower in many cases.');
+    log.info('[bazel_tools] reach out to Operations if you need assistance with this.');
+    return;
+  }
+
+  let apiKey = '';
+
+  try {
+    const { stdout } = await spawn(
+      'vault',
+      ['read', '-field=readonly-key', 'secret/kibana-issues/dev/bazel-remote-cache'],
+      {
+        stdio: 'pipe',
+      }
+    );
+    apiKey = stdout.trim();
+  } catch (ex: unknown) {
+    log.info(
+      '[bazel_tools] unable to read bazel remote cache key from vault, are you authenticated?'
+    );
+    log.info('[bazel_tools] building packages will work, but will be slower in many cases.');
+    log.info('[bazel_tools] reach out to Operations if you need assistance with this.');
+    log.info(`[bazel_tools] ${ex}`);
+
+    return;
+  }
+
+  const contents = dedent`
+    # V1 - This file is automatically generated by 'yarn kbn bootstrap'
+    # To regenerate this file, delete it and run 'yarn kbn bootstrap' again.
+    build --bes_results_url=https://app.buildbuddy.io/invocation/
+    build --bes_backend=grpcs://cloud.buildbuddy.io
+    build --remote_cache=grpcs://cloud.buildbuddy.io
+    build --remote_timeout=3600
+    build --remote_header=${apiKey}
+  `;
+
+  writeFileSync(settingsPath, contents);
+  log.info(`[bazel_tools] remote cache settings written to ${settingsPath}`);
+}