feat(serverless): optionally wait for run task to exit

Author: apaleslimghost

plugins/serverless/src/tasks/run.ts

@@ -2,10 +2,11 @@ import { Task, TaskRunContext } from '@dotcom-tool-kit/base'
 import type ServerlessSchema from '../schema'
 import { ChildProcess, spawn } from 'child_process'
 import { DopplerEnvVars } from '@dotcom-tool-kit/doppler'
-import { hookConsole, hookFork } from '@dotcom-tool-kit/logger'
+import { hookConsole, hookFork, waitOnExit, styles as s } from '@dotcom-tool-kit/logger'
 import getPort from 'get-port'
 import waitPort from 'wait-port'
 import * as z from 'zod'
+import { writeState } from '@dotcom-tool-kit/state'
 
 const ServerlessRunSchema = z
   .object({
@@ -17,7 +18,18 @@ const ServerlessRunSchema = z
     useDoppler: z
       .boolean()
       .default(true)
-      .describe('run the application with environment variables from Doppler')
+      .describe('run the application with environment variables from Doppler'),
+    background: z
+      .boolean()
+      .optional()
+      .transform((background) => ({
+        isDefault: typeof background === 'undefined',
+        value: typeof background === 'undefined' ? true : background
+      }))
+      .default(true) // will never be reached because of the transform; here for the documentation generator's benefit
+      .describe(
+        "run the `serverless oflfine` process in the background, i.e. don't wait for it to exit before continuing to other Tool Kit tasks. set to `false` to wait for the process to exit, useful for running [multiple Tool Kit tasks in parallel](../parallel)."
+      )
   })
   .describe('Run serverless functions locally')
 export { ServerlessRunSchema as schema }
@@ -71,11 +83,27 @@ export default class ServerlessRun extends Task<{
     try {
       await waitPort({
         host: 'localhost',
-        port: port
+        port
       })
     } finally {
       unhook()
     }
+
+    writeState('local', { port })
+
+    if (this.options.background.isDefault) {
+      this.logger.warn(
+        `${s.task('ServerlessRun')} ${s.option(
+          'options.background'
+        )} is not set; falling back to the legacy behaviour of running the process in the background. This will be removed in a future major version of ${s.plugin(
+          '@dotcom-tool-kit/serverless'
+        )}.`
+      )
+    }
+
+    if (!this.options.background.value) {
+      await waitOnExit('serverless', this.child)
+    }
   }
 
   async stop() {