Extract container service and helpers from updater

Moving some shared bits out of the updater class to reduce bloat.

__tests__/container-service.test.ts

@@ -0,0 +1,24 @@
+import Docker from 'dockerode'
+
+import {ContainerService} from '../src/container-service'
+import {ImageService} from '../src/image-service'
+
+describe('ContainerService', () => {
+  const docker = new Docker()
+  let container: any
+
+  beforeAll(async () => {
+    await ImageService.pull('alpine')
+    container = await docker.createContainer({
+      Image: 'alpine',
+      AttachStdout: true,
+      AttachStderr: true,
+      Cmd: ['/bin/sh', '-c', 'echo $VAR'],
+      Env: ['VAR=env-var']
+    })
+  })
+
+  test('runs containers', async () => {
+    await ContainerService.run(container)
+  })
+})

__tests__/utils.test.ts

@@ -0,0 +1,20 @@
+import {base64DecodeDependencyFile} from '../src/utils'
+
+describe('base64DecodeDependencyFile', () => {
+  test('clones the dependency file', () => {
+    const dependencyFile = {
+      name: 'package.json',
+      content: 'dGVzdCBzdHJpbmc=',
+      directory: '/',
+      type: 'file',
+      support_file: false,
+      content_encoding: 'utf-8',
+      deleted: false,
+      operation: 'add'
+    }
+
+    const decoded = base64DecodeDependencyFile(dependencyFile)
+    expect(decoded.content).toEqual('test string')
+    expect(dependencyFile.content).toEqual('dGVzdCBzdHJpbmc=')
+  })
+})

src/container-service.ts

@@ -0,0 +1,35 @@
+import * as core from '@actions/core'
+import {Container} from 'dockerode'
+import {pack} from 'tar-stream'
+import {FileFetcherInput, FileUpdaterInput} from './file-types'
+
+export const ContainerService = {
+  async storeInput(
+    name: string,
+    path: string,
+    container: Container,
+    input: FileFetcherInput | FileUpdaterInput
+  ): Promise<void> {
+    const tar = pack()
+    tar.entry({name}, JSON.stringify(input))
+    tar.finalize()
+    await container.putArchive(tar, {path})
+  },
+
+  async run(container: Container): Promise<void> {
+    try {
+      const stream = await container.attach({
+        stream: true,
+        stdout: true,
+        stderr: true
+      })
+      container.modem.demuxStream(stream, process.stdout, process.stderr)
+
+      await container.start()
+      await container.wait()
+    } finally {
+      await container.remove()
+      core.info(`Cleaned up container ${container.id}`)
+    }
+  }
+}

src/file-types.ts

@@ -0,0 +1,27 @@
+import {Credential, JobDetails} from './api-client'
+
+export type FetchedFiles = {
+  base_commit_sha: string
+  dependency_files: any[]
+  base64_dependency_files: any[]
+}
+
+export type FileFetcherInput = {
+  job: JobDetails
+  credentials: Credential[]
+}
+
+export type DependencyFile = {
+  name: string
+  content: any
+  directory: string
+  type: string
+  support_file: boolean
+  content_encoding: string
+  deleted: boolean
+  operation: string
+}
+
+export type FileUpdaterInput = FetchedFiles & {
+  job: JobDetails
+}

src/updater.ts

@@ -3,17 +3,16 @@ import Docker, {Container} from 'dockerode'
 import path from 'path'
 import fs from 'fs'
 import {Credential, JobDetails, APIClient} from './api-client'
-import {pack} from 'tar-stream'
+import {ContainerService} from './container-service'
+import {base64DecodeDependencyFile} from './utils'
+import {DependencyFile, FetchedFiles, FileUpdaterInput} from './file-types'
 
 const JOB_INPUT_FILENAME = 'job.json'
 const JOB_INPUT_PATH = `/home/dependabot/dependabot-updater`
 const JOB_OUTPUT_FILENAME = 'output.json'
 const JOB_OUTPUT_PATH = '/home/dependabot/dependabot-updater/output'
 const REPO_CONTENTS_PATH = '/home/dependabot/dependabot-updater/repo'
 
-const decode = (str: string): string =>
-  Buffer.from(str, 'base64').toString('binary')
-
 export class Updater {
   docker: Docker
   constructor(
@@ -47,22 +46,21 @@ export class Updater {
     }
   }
 
-  private decodeBase64Content(file: DependencyFile): string {
-    const fileCopy = JSON.parse(JSON.stringify(file))
-    fileCopy.content = decode(fileCopy.content)
-    return fileCopy
-  }
-
   private async runFileFetcher(
     details: JobDetails,
     credentials: Credential[]
   ): Promise<void | FetchedFiles> {
     const container = await this.createContainer('fetch_files')
-    await this.storeContainerInput(container, {
-      job: details,
-      credentials
-    })
-    await this.runContainer(container)
+    await ContainerService.storeInput(
+      JOB_INPUT_FILENAME,
+      JOB_INPUT_PATH,
+      container,
+      {
+        job: details,
+        credentials
+      }
+    )
+    await ContainerService.run(container)
 
     const outputPath = path.join(__dirname, '../output/output.json')
     if (!fs.existsSync(outputPath)) {
@@ -76,7 +74,7 @@ export class Updater {
       base_commit_sha: fileFetcherOutput.base_commit_sha,
       base64_dependency_files: fileFetcherOutput.base64_dependency_files,
       dependency_files: fileFetcherOutput.base64_dependency_files.map(
-        (file: DependencyFile) => this.decodeBase64Content(file)
+        (file: DependencyFile) => base64DecodeDependencyFile(file)
       )
     }
 
@@ -95,8 +93,13 @@ export class Updater {
       dependency_files: files.dependency_files,
       job: details
     }
-    await this.storeContainerInput(container, containerInput)
-    await this.runContainer(container)
+    await ContainerService.storeInput(
+      JOB_INPUT_FILENAME,
+      JOB_INPUT_PATH,
+      container,
+      containerInput
+    )
+    await ContainerService.run(container)
   }
 
   private async createContainer(updaterCommand: string): Promise<Container> {
@@ -125,57 +128,4 @@ export class Updater {
     core.info(`Created ${updaterCommand} container: ${container.id}`)
     return container
   }
-
-  private async storeContainerInput(
-    container: Container,
-    input: FileFetcherInput | FileUpdaterInput
-  ): Promise<void> {
-    const tar = pack()
-    tar.entry({name: JOB_INPUT_FILENAME}, JSON.stringify(input))
-    tar.finalize()
-    await container.putArchive(tar, {path: JOB_INPUT_PATH})
-  }
-
-  private async runContainer(container: Container): Promise<void> {
-    try {
-      await container.start()
-      const stream = await container.attach({
-        stream: true,
-        stdout: true,
-        stderr: true
-      })
-      container.modem.demuxStream(stream, process.stdout, process.stderr)
-
-      await container.wait()
-    } finally {
-      await container.remove()
-      core.info(`Cleaned up container ${container.id}`)
-    }
-  }
-}
-
-type FileFetcherInput = {
-  job: JobDetails
-  credentials: Credential[]
-}
-
-type FetchedFiles = {
-  base_commit_sha: string
-  dependency_files: any[]
-  base64_dependency_files: any[]
-}
-
-type DependencyFile = {
-  name: string
-  content: any
-  directory: string
-  type: string
-  support_file: boolean
-  content_encoding: string
-  deleted: boolean
-  operation: string
-}
-
-type FileUpdaterInput = FetchedFiles & {
-  job: JobDetails
 }

src/utils.ts

@@ -0,0 +1,12 @@
+import {DependencyFile} from './file-types'
+
+const base64Decode = (str: string): string =>
+  Buffer.from(str, 'base64').toString('binary')
+
+export const base64DecodeDependencyFile = (
+  file: DependencyFile
+): DependencyFile => {
+  const fileCopy = JSON.parse(JSON.stringify(file))
+  fileCopy.content = base64Decode(fileCopy.content)
+  return fileCopy
+}