feat(serve): add a --watch flag for serve mode

When watch is enabled, ncdc will watch your config file and fixtures for changes. If changes are
detected, the ncdc server will restart

fix #28

acceptance-tests/cli-wrapper.ts

@@ -2,9 +2,8 @@ import { ChildProcess, exec } from 'child_process'
 import strip from 'strip-ansi'
 import isomorphicUnfetch from 'isomorphic-unfetch'
 
-const waitForX = (condition: () => Promise<boolean> | boolean): Promise<void> =>
+const waitForX = (condition: () => Promise<boolean> | boolean, timeout: number): Promise<void> =>
   new Promise<void>((resolve, reject) => {
-    const timeout = 10
     const retryPeriod = 0.5
     let tries = 0
 
@@ -56,9 +55,9 @@ export type CleanupTask = () => void
 export const fetch = (endpoint: string, init?: RequestInit): Promise<Response> =>
   isomorphicUnfetch(`${SERVE_HOST}${endpoint}`, init)
 
-export const prepareServe = (cleanupTasks: CleanupTask[]) => async (
-  checkAvailability = true,
+export const prepareServe = (cleanupTasks: CleanupTask[], timeout = 5) => async (
   args = '',
+  checkAvailability = true,
 ): Promise<ServeResult> => {
   let hasExited = false
   const command = `LOG_LEVEL=debug CHOKIDAR_USEPOLLING=1 ./bin/ncdc serve ${CONFIG_FILE} -c ${FIXTURE_FOLDER}/tsconfig.json ${args}`
@@ -99,7 +98,7 @@ export const prepareServe = (cleanupTasks: CleanupTask[]) => async (
       const foundIndex = searchableOutput.findIndex((s) => {
         if (typeof target === 'string') return strip(s).includes(target)
         return target.test(s)
-      })
+      }, timeout)
 
       if (foundIndex === -1) {
         outputPointer = currentOutput.length
@@ -108,7 +107,7 @@ export const prepareServe = (cleanupTasks: CleanupTask[]) => async (
 
       outputPointer += foundIndex + 1
       return true
-    }).catch(
+    }, timeout).catch(
       failNicely(
         `Did not find the string "${target}" in the output${
           outputPointer ? ' on or after message ' + outputPointer : ''
@@ -121,7 +120,7 @@ export const prepareServe = (cleanupTasks: CleanupTask[]) => async (
     waitForX(async () => {
       const { status } = await fetch('/')
       return status === 200
-    }).catch(failNicely(`The ncdc server was not contactable at ${SERVE_HOST}/`))
+    }, timeout).catch(failNicely(`The ncdc server was not contactable at ${SERVE_HOST}/`))
 
   if (checkAvailability) await waitUntilAvailable()
   return { getAllOutput: () => strip(getRawOutput()), waitForOutput, waitUntilAvailable }

acceptance-tests/serve.spec.ts

@@ -60,7 +60,7 @@ describe('ncdc serve', () => {
     )
 
     // act
-    const { waitForOutput } = await serve(false)
+    const { waitForOutput } = await serve('', false)
 
     // assert
     await waitForOutput('no such file or directory')
@@ -70,7 +70,7 @@ describe('ncdc serve', () => {
   it('restarts when config.yml is changed', async () => {
     // arrange
     const configWrapper = new ConfigWrapper().addConfig()
-    const { waitForOutput, waitUntilAvailable } = await serve()
+    const { waitForOutput, waitUntilAvailable } = await serve('--watch')
     const resInitial = await fetch('/api/books/789')
     expect(resInitial.status).toBe(200)
 
@@ -87,7 +87,7 @@ describe('ncdc serve', () => {
   it('logs a message and kills the server when config.yml has been deleted', async () => {
     // arrange
     const configWrapper = new ConfigWrapper().addConfig()
-    const { waitForOutput } = await serve()
+    const { waitForOutput } = await serve('--watch')
     const resInitial = await fetch('/api/books/yay')
     expect(resInitial.status).toBe(200)
 
@@ -103,7 +103,7 @@ describe('ncdc serve', () => {
   it('can recover from config.yml being deleted when file is re-added', async () => {
     // arrange
     const configWrapper = new ConfigWrapper().addConfig()
-    const { waitForOutput } = await serve()
+    const { waitForOutput } = await serve('--watch')
     configWrapper.deleteYaml()
     await waitForOutput(MESSAGE_RSTARTING_FAILURE)
 
@@ -130,7 +130,7 @@ describe('ncdc serve', () => {
       })
 
     // act
-    const { waitForOutput, waitUntilAvailable } = await serve()
+    const { waitForOutput, waitUntilAvailable } = await serve('--watch')
     configWrapper.editFixture(fixtureName, (f) => ({ ...f, title: 'shit meme' }))
 
     await waitForOutput(/change event detected for .*response.json/)
@@ -156,7 +156,7 @@ describe('ncdc serve', () => {
       })
 
     // act
-    const { waitForOutput } = await serve()
+    const { waitForOutput } = await serve('--watch')
     configWrapper.deleteFixture(fixtureName)
 
     // assert
@@ -175,7 +175,7 @@ describe('ncdc serve', () => {
         author: 'me',
       })
 
-    const { waitForOutput, waitUntilAvailable } = await serve()
+    const { waitForOutput, waitUntilAvailable } = await serve('--watch')
     configWrapper.deleteFixture(fixtureName)
     await waitForOutput(MESSAGE_RSTARTING_FAILURE)
 
@@ -211,7 +211,7 @@ describe('ncdc serve', () => {
           title: 'string',
         })
 
-      serve = await prepareServe(typecheckingCleanup)()
+      serve = await prepareServe(typecheckingCleanup, 10)('--watch')
 
       await expect(fetch('/api/books/hello')).resolves.toMatchObject({ status: 200 })
     })

docker-compose.yml

@@ -16,3 +16,9 @@ services:
       - TEST_MODE=acceptance
     volumes:
       - ./:/usr/src/app
+
+  acceptance:
+    build: .
+    command: bash -c 'yarn compile && yarn test'
+    environment:
+      - TEST_MODE=acceptance

src/commands/serve/handler.spec.ts

@@ -44,13 +44,19 @@ describe('handler', () => {
   })
 
   it('handles when a config path is not supplied', async () => {
-    await handler({ force: false, port: 8001, tsconfigPath: randomString() })
+    await handler({ force: false, port: 8001, tsconfigPath: randomString(), watch: false })
 
     expect(mockHandleError).toBeCalledWith({ message: 'config path must be supplied' })
   })
 
   it('handles when port is not a number', async () => {
-    await handler({ force: false, port: NaN, tsconfigPath: randomString(), configPath: randomString() })
+    await handler({
+      force: false,
+      port: NaN,
+      tsconfigPath: randomString(),
+      configPath: randomString(),
+      watch: false,
+    })
 
     expect(mockHandleError).toBeCalledWith({ message: 'port must be a number' })
   })
@@ -60,6 +66,7 @@ describe('handler', () => {
     port: 4000,
     tsconfigPath: randomString(),
     configPath: randomString(),
+    watch: false,
   }
 
   describe('runs the server with the correct configs', () => {

src/commands/serve/handler.ts

@@ -13,6 +13,7 @@ export interface ServeArgs {
   tsconfigPath: string
   schemaPath?: string
   force: boolean
+  watch: boolean
 }
 
 export type StartServer = (port: number, routes: Config[], typeValidator?: TypeValidator) => StartServerResult
@@ -64,7 +65,7 @@ const createHandler = (
   createTypeValidator: CreateTypeValidator,
   startServer: StartServer,
 ) => async (args: ServeArgs): Promise<void> => {
-  const { configPath, port, tsconfigPath, schemaPath, force } = args
+  const { configPath, port, tsconfigPath, schemaPath, force, watch } = args
 
   if (!configPath) return handleError({ message: 'config path must be supplied' })
   if (isNaN(port)) return handleError({ message: 'port must be a number' })
@@ -114,36 +115,38 @@ const createHandler = (
     return handleError(err)
   }
 
-  const configWatcher = chokidar.watch([absoluteConfigPath, ...result.pathsToWatch], {
-    ignoreInitial: true,
-  })
+  if (watch) {
+    const configWatcher = chokidar.watch([absoluteConfigPath, ...result.pathsToWatch], {
+      ignoreInitial: true,
+    })
 
-  configWatcher.on('all', async (e, path) => {
-    logger.info(`${e} event detected for ${path}`)
-    logger.info('Attempting to restart ncdc server')
+    configWatcher.on('all', async (e, path) => {
+      logger.info(`${e} event detected for ${path}`)
+      logger.info('Attempting to restart ncdc server')
 
-    if (e === 'unlink') {
-      // makes sure that we can still watch the file for changes after its deletion
-      configWatcher.add(path)
-    }
+      if (e === 'unlink') {
+        // makes sure that we can still watch the file for changes after its deletion
+        configWatcher.add(path)
+      }
 
-    try {
-      await result.startServerResult.close()
-    } catch (err) {
-      logger.error(`Could not restart the server: ${err.message}`)
-      return
-    }
+      try {
+        await result.startServerResult.close()
+      } catch (err) {
+        logger.error(`Could not restart the server: ${err.message}`)
+        return
+      }
 
-    try {
-      result = await prepAndStartServer()
-    } catch (err) {
-      logger.error(`Could not restart ncdc server: ${err.message}`)
-      return
-    }
+      try {
+        result = await prepAndStartServer()
+      } catch (err) {
+        logger.error(`Could not restart ncdc server: ${err.message}`)
+        return
+      }
 
-    configWatcher.unwatch('**/*')
-    configWatcher.add([absoluteConfigPath, ...result.pathsToWatch])
-  })
+      configWatcher.unwatch('**/*')
+      configWatcher.add([absoluteConfigPath, ...result.pathsToWatch])
+    })
+  }
 }
 
 export default createHandler

src/commands/serve/index.ts

@@ -16,6 +16,11 @@ const builder = (yargs: Argv): Argv<ServeArgs> =>
       type: 'number',
       default: 4000,
     })
+    .option('watch', {
+      describe: 'watches the provided config file and fixtures then restarts if there are changes',
+      type: 'boolean',
+      default: false,
+    })
     .option(consts.SCHEMA_PATH, {
       type: consts.SCHEMA_PATH_TYPE,
       description: consts.SCHEMA_PATH_DESCRIPTION,