migrate pid file to core (#77037)

* migrate pid file to core

* use correct log level + add comment

* move `unhandledRejection` to service's setup

* update comment

src/core/server/environment/environment_service.test.ts

@@ -21,6 +21,7 @@ import { BehaviorSubject } from 'rxjs';
 import { EnvironmentService } from './environment_service';
 import { resolveInstanceUuid } from './resolve_uuid';
 import { createDataFolder } from './create_data_folder';
+import { writePidFile } from './write_pid_file';
 import { CoreContext } from '../core_context';
 
 import { configServiceMock } from '../config/config_service.mock';
@@ -35,12 +36,20 @@ jest.mock('./create_data_folder', () => ({
   createDataFolder: jest.fn(),
 }));
 
+jest.mock('./write_pid_file', () => ({
+  writePidFile: jest.fn(),
+}));
+
 const pathConfig = {
   data: 'data-folder',
 };
 const serverConfig = {
   uuid: 'SOME_UUID',
 };
+const pidConfig = {
+  file: '/pid/file',
+  exclusive: 'false',
+};
 
 const getConfigService = () => {
   const configService = configServiceMock.create();
@@ -51,6 +60,9 @@ const getConfigService = () => {
     if (path === 'server') {
       return new BehaviorSubject(serverConfig);
     }
+    if (path === 'pid') {
+      return new BehaviorSubject(pidConfig);
+    }
     return new BehaviorSubject({});
   });
   return configService;
@@ -76,7 +88,7 @@ describe('UuidService', () => {
       expect(resolveInstanceUuid).toHaveBeenCalledWith({
         pathConfig,
         serverConfig,
-        logger: logger.get('uuid'),
+        logger: logger.get('environment'),
       });
     });
 
@@ -86,7 +98,17 @@ describe('UuidService', () => {
       expect(createDataFolder).toHaveBeenCalledTimes(1);
       expect(createDataFolder).toHaveBeenCalledWith({
         pathConfig,
-        logger: logger.get('uuid'),
+        logger: logger.get('environment'),
+      });
+    });
+
+    it('calls writePidFile with correct parameters', async () => {
+      const service = new EnvironmentService(coreContext);
+      await service.setup();
+      expect(writePidFile).toHaveBeenCalledTimes(1);
+      expect(writePidFile).toHaveBeenCalledWith({
+        pidConfig,
+        logger: logger.get('environment'),
       });
     });
 

src/core/server/environment/environment_service.ts

@@ -23,8 +23,10 @@ import { Logger } from '../logging';
 import { IConfigService } from '../config';
 import { PathConfigType, config as pathConfigDef } from '../path';
 import { HttpConfigType, config as httpConfigDef } from '../http';
+import { PidConfigType, config as pidConfigDef } from './pid_config';
 import { resolveInstanceUuid } from './resolve_uuid';
 import { createDataFolder } from './create_data_folder';
+import { writePidFile } from './write_pid_file';
 
 /**
  * @internal
@@ -43,17 +45,24 @@ export class EnvironmentService {
   private uuid: string = '';
 
   constructor(core: CoreContext) {
-    this.log = core.logger.get('uuid');
+    this.log = core.logger.get('environment');
     this.configService = core.configService;
   }
 
   public async setup() {
-    const [pathConfig, serverConfig] = await Promise.all([
+    const [pathConfig, serverConfig, pidConfig] = await Promise.all([
       this.configService.atPath<PathConfigType>(pathConfigDef.path).pipe(take(1)).toPromise(),
       this.configService.atPath<HttpConfigType>(httpConfigDef.path).pipe(take(1)).toPromise(),
+      this.configService.atPath<PidConfigType>(pidConfigDef.path).pipe(take(1)).toPromise(),
     ]);
 
+    // was present in the legacy `pid` file.
+    process.on('unhandledRejection', (reason) => {
+      this.log.warn(`Detected an unhandled Promise rejection.\n${reason}`);
+    });
+
     await createDataFolder({ pathConfig, logger: this.log });
+    await writePidFile({ pidConfig, logger: this.log });
 
     this.uuid = await resolveInstanceUuid({
       pathConfig,

src/core/server/environment/fs.ts

@@ -23,3 +23,4 @@ import { promisify } from 'util';
 export const readFile = promisify(Fs.readFile);
 export const writeFile = promisify(Fs.writeFile);
 export const mkdir = promisify(Fs.mkdir);
+export const exists = promisify(Fs.exists);

src/core/server/environment/index.ts

@@ -18,3 +18,4 @@
  */
 
 export { EnvironmentService, InternalEnvironmentServiceSetup } from './environment_service';
+export { config, PidConfigType } from './pid_config';

src/core/server/environment/pid_config.ts

@@ -0,0 +1,30 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { TypeOf, schema } from '@kbn/config-schema';
+
+export const config = {
+  path: 'pid',
+  schema: schema.object({
+    file: schema.maybe(schema.string()),
+    exclusive: schema.boolean({ defaultValue: false }),
+  }),
+};
+
+export type PidConfigType = TypeOf<typeof config.schema>;

src/core/server/environment/write_pid_file.test.ts

@@ -0,0 +1,144 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { writeFile, exists } from './fs';
+import { writePidFile } from './write_pid_file';
+import { loggingSystemMock } from '../logging/logging_system.mock';
+
+jest.mock('./fs', () => ({
+  writeFile: jest.fn(),
+  exists: jest.fn(),
+}));
+
+const writeFileMock = writeFile as jest.MockedFunction<typeof writeFile>;
+const existsMock = exists as jest.MockedFunction<typeof exists>;
+
+const pid = String(process.pid);
+
+describe('writePidFile', () => {
+  let logger: ReturnType<typeof loggingSystemMock.createLogger>;
+
+  beforeEach(() => {
+    logger = loggingSystemMock.createLogger();
+    jest.spyOn(process, 'once');
+
+    writeFileMock.mockImplementation(() => Promise.resolve());
+    existsMock.mockImplementation(() => Promise.resolve(false));
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  const allLogs = () =>
+    Object.entries(loggingSystemMock.collect(logger)).reduce((messages, [key, value]) => {
+      return [...messages, ...(key === 'log' ? [] : (value as any[]).map(([msg]) => [key, msg]))];
+    }, [] as any[]);
+
+  it('does nothing if `pid.file` is not set', async () => {
+    await writePidFile({
+      pidConfig: {
+        file: undefined,
+        exclusive: false,
+      },
+      logger,
+    });
+    expect(writeFile).not.toHaveBeenCalled();
+    expect(process.once).not.toHaveBeenCalled();
+    expect(allLogs()).toMatchInlineSnapshot(`Array []`);
+  });
+
+  it('writes the pid file to `pid.file`', async () => {
+    existsMock.mockResolvedValue(false);
+
+    await writePidFile({
+      pidConfig: {
+        file: '/pid-file',
+        exclusive: false,
+      },
+      logger,
+    });
+
+    expect(writeFile).toHaveBeenCalledTimes(1);
+    expect(writeFile).toHaveBeenCalledWith('/pid-file', pid);
+
+    expect(process.once).toHaveBeenCalledTimes(2);
+    expect(process.once).toHaveBeenCalledWith('exit', expect.any(Function));
+    expect(process.once).toHaveBeenCalledWith('SIGINT', expect.any(Function));
+
+    expect(allLogs()).toMatchInlineSnapshot(`
+      Array [
+        Array [
+          "debug",
+          "wrote pid file to /pid-file",
+        ],
+      ]
+    `);
+  });
+
+  it('throws an error if the file exists and `pid.exclusive is true`', async () => {
+    existsMock.mockResolvedValue(true);
+
+    await expect(
+      writePidFile({
+        pidConfig: {
+          file: '/pid-file',
+          exclusive: true,
+        },
+        logger,
+      })
+    ).rejects.toThrowErrorMatchingInlineSnapshot(`"pid file already exists at /pid-file"`);
+
+    expect(writeFile).not.toHaveBeenCalled();
+    expect(process.once).not.toHaveBeenCalled();
+    expect(allLogs()).toMatchInlineSnapshot(`Array []`);
+  });
+
+  it('logs a warning if the file exists and `pid.exclusive` is false', async () => {
+    existsMock.mockResolvedValue(true);
+
+    await writePidFile({
+      pidConfig: {
+        file: '/pid-file',
+        exclusive: false,
+      },
+      logger,
+    });
+
+    expect(writeFile).toHaveBeenCalledTimes(1);
+    expect(writeFile).toHaveBeenCalledWith('/pid-file', pid);
+
+    expect(process.once).toHaveBeenCalledTimes(2);
+    expect(process.once).toHaveBeenCalledWith('exit', expect.any(Function));
+    expect(process.once).toHaveBeenCalledWith('SIGINT', expect.any(Function));
+
+    expect(allLogs()).toMatchInlineSnapshot(`
+      Array [
+        Array [
+          "debug",
+          "wrote pid file to /pid-file",
+        ],
+        Array [
+          "warn",
+          "pid file already exists at /pid-file",
+        ],
+      ]
+    `);
+  });
+});

src/core/server/environment/write_pid_file.ts

@@ -0,0 +1,64 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { unlinkSync as unlink } from 'fs';
+import once from 'lodash/once';
+import { Logger } from '../logging';
+import { writeFile, exists } from './fs';
+import { PidConfigType } from './pid_config';
+
+export const writePidFile = async ({
+  pidConfig,
+  logger,
+}: {
+  pidConfig: PidConfigType;
+  logger: Logger;
+}) => {
+  const path = pidConfig.file;
+  if (!path) {
+    return;
+  }
+
+  const pid = String(process.pid);
+
+  if (await exists(path)) {
+    const message = `pid file already exists at ${path}`;
+    if (pidConfig.exclusive) {
+      throw new Error(message);
+    } else {
+      logger.warn(message, { path, pid });
+    }
+  }
+
+  await writeFile(path, pid);
+
+  logger.debug(`wrote pid file to ${path}`, { path, pid });
+
+  const clean = once(() => {
+    unlink(path);
+  });
+
+  process.once('exit', clean); // for "natural" exits
+  process.once('SIGINT', () => {
+    // for Ctrl-C exits
+    clean();
+    // resend SIGINT
+    process.kill(process.pid, 'SIGINT');
+  });
+};

src/core/server/server.ts

@@ -31,7 +31,7 @@ import { PluginsService, config as pluginsConfig } from './plugins';
 import { SavedObjectsService } from '../server/saved_objects';
 import { MetricsService, opsConfig } from './metrics';
 import { CapabilitiesService } from './capabilities';
-import { EnvironmentService } from './environment';
+import { EnvironmentService, config as pidConfig } from './environment';
 import { StatusService } from './status/status_service';
 
 import { config as cspConfig } from './csp';
@@ -310,6 +310,7 @@ export class Server {
       uiSettingsConfig,
       opsConfig,
       statusConfig,
+      pidConfig,
     ];
 
     this.configService.addDeprecationProvider(rootConfigPath, coreDeprecationProvider);

src/legacy/server/config/schema.js

@@ -42,10 +42,7 @@ export default () =>
       basePathProxyTarget: Joi.number().default(5603),
     }).default(),
 
-    pid: Joi.object({
-      file: Joi.string(),
-      exclusive: Joi.boolean().default(false),
-    }).default(),
+    pid: HANDLED_IN_NEW_PLATFORM,
 
     csp: HANDLED_IN_NEW_PLATFORM,