chore(core): show Docker build output for BundlingDockerImage.fromAsset()

Remove the `-q` option and use a known tag derived from the path to the
Dockerfile and the build options.

Author: jogold

packages/@aws-cdk/core/lib/bundling.ts

@@ -1,4 +1,5 @@
 import { spawnSync, SpawnSyncOptions } from 'child_process';
+import * as crypto from 'crypto';
 import { FileSystem } from './fs';
 
 /**
@@ -108,28 +109,29 @@ export class BundlingDockerImage {
   public static fromAsset(path: string, options: DockerBuildOptions = {}) {
     const buildArgs = options.buildArgs || {};
 
+    // Image tag derived from path and build options
+    const tagHash = crypto.createHash('sha256').update(JSON.stringify({
+      path,
+      ...options,
+    })).digest('hex');
+    const tag = `cdk-${tagHash}`;
+
     const dockerArgs: string[] = [
-      'build', '-q',
+      'build', '-t', tag,
       ...(options.file ? ['-f', options.file] : []),
       ...flatten(Object.entries(buildArgs).map(([k, v]) => ['--build-arg', `${k}=${v}`])),
       path,
     ];
 
-    const docker = dockerExec(dockerArgs);
-
-    const match = docker.stdout.toString().match(/sha256:[a-z0-9]+/);
-
-    if (!match) {
-      throw new Error('Failed to extract image ID from Docker build output');
-    }
+    dockerExec(dockerArgs);
 
     // Fingerprints the directory containing the Dockerfile we're building and
     // differentiates the fingerprint based on build arguments. We do this so
     // we can provide a stable image hash. Otherwise, the image ID will be
     // different every time the Docker layer cache is cleared, due primarily to
     // timestamps.
     const hash = FileSystem.fingerprint(path, { extraHash: JSON.stringify(options) });
-    return new BundlingDockerImage(match[0], hash);
+    return new BundlingDockerImage(tag, hash);
   }
 
   /** @param image The Docker image */
@@ -166,13 +168,7 @@ export class BundlingDockerImage {
       ...command,
     ];
 
-    dockerExec(dockerArgs, {
-      stdio: [ // show Docker output
-        'ignore', // ignore stdio
-        process.stderr, // redirect stdout to stderr
-        'inherit', // inherit stderr
-      ],
-    });
+    dockerExec(dockerArgs);
   }
 
   /**
@@ -303,7 +299,13 @@ function flatten(x: string[][]) {
 
 function dockerExec(args: string[], options?: SpawnSyncOptions) {
   const prog = process.env.CDK_DOCKER ?? 'docker';
-  const proc = spawnSync(prog, args, options);
+  const proc = spawnSync(prog, args, options ?? {
+    stdio: [ // show Docker output
+      'ignore', // ignore stdio
+      process.stderr, // redirect stdout to stderr
+      'inherit', // inherit stderr
+    ],
+  });
 
   if (proc.error) {
     throw proc.error;

packages/@aws-cdk/core/test/bundling.test.ts

@@ -1,4 +1,5 @@
 import * as child_process from 'child_process';
+import * as crypto from 'crypto';
 import * as path from 'path';
 import { nodeunitShim, Test } from 'nodeunit-shim';
 import * as sinon from 'sinon';
@@ -46,11 +47,10 @@ nodeunitShim({
   },
 
   'bundling with image from asset'(test: Test) {
-    const imageId = 'sha256:abcdef123456';
     const spawnSyncStub = sinon.stub(child_process, 'spawnSync').returns({
       status: 0,
       stderr: Buffer.from('stderr'),
-      stdout: Buffer.from(imageId),
+      stdout: Buffer.from('stdout'),
       pid: 123,
       output: ['stdout', 'stderr'],
       signal: null,
@@ -67,33 +67,27 @@ nodeunitShim({
     });
     image.run();
 
+    const tagHash = crypto.createHash('sha256').update(JSON.stringify({
+      path: 'docker-path',
+      buildArgs: {
+        TEST_ARG: 'cdk-test',
+      },
+    })).digest('hex');
+    const tag = `cdk-${tagHash}`;
+
     test.ok(spawnSyncStub.firstCall.calledWith('docker', [
-      'build', '-q',
+      'build', '-t', tag,
       '--build-arg', 'TEST_ARG=cdk-test',
       'docker-path',
     ]));
 
     test.ok(spawnSyncStub.secondCall.calledWith('docker', [
       'run', '--rm',
-      imageId,
+      tag,
     ]));
     test.done();
   },
 
-  'throws if image id cannot be extracted from build output'(test: Test) {
-    sinon.stub(child_process, 'spawnSync').returns({
-      status: 0,
-      stderr: Buffer.from('stderr'),
-      stdout: Buffer.from('stdout'),
-      pid: 123,
-      output: ['stdout', 'stderr'],
-      signal: null,
-    });
-
-    test.throws(() => BundlingDockerImage.fromAsset('docker-path'), /Failed to extract image ID from Docker build output/);
-    test.done();
-  },
-
   'throws in case of spawnSync error'(test: Test) {
     sinon.stub(child_process, 'spawnSync').returns({
       status: 0,
@@ -133,11 +127,10 @@ nodeunitShim({
   },
 
   'BundlerDockerImage json is the bundler image if building an image'(test: Test) {
-    const imageId = 'sha256:abcdef123456';
     sinon.stub(child_process, 'spawnSync').returns({
       status: 0,
       stderr: Buffer.from('stderr'),
-      stdout: Buffer.from(imageId),
+      stdout: Buffer.from('stdout'),
       pid: 123,
       output: ['stdout', 'stderr'],
       signal: null,
@@ -148,7 +141,11 @@ nodeunitShim({
 
     const image = BundlingDockerImage.fromAsset('docker-path');
 
-    test.equals(image.image, imageId);
+    const tagHash = crypto.createHash('sha256').update(JSON.stringify({
+      path: 'docker-path',
+    })).digest('hex');
+
+    test.equals(image.image, `cdk-${tagHash}`);
     test.equals(image.toJSON(), imageHash);
     test.ok(fingerprintStub.calledWith('docker-path', sinon.match({ extraHash: JSON.stringify({}) })));
     test.done();