fix(ecr-assets): docker images are not built if .dockerignore includes an entry that ignores the dockerfile.

package.json

@@ -49,6 +49,8 @@
       "**/jszip/**",
       "@aws-cdk/assets/minimatch",
       "@aws-cdk/assets/minimatch/**",
+      "@aws-cdk/aws-ecr-assets/minimatch",
+      "@aws-cdk/aws-ecr-assets/minimatch/**",
       "@aws-cdk/cx-api/semver",
       "@aws-cdk/cx-api/semver/**",
       "@aws-cdk/cx-api/semver/**",

packages/@aws-cdk/aws-ecr-assets/lib/image-asset.ts

@@ -2,6 +2,7 @@ import * as assets from '@aws-cdk/assets';
 import * as ecr from '@aws-cdk/aws-ecr';
 import { Construct, Stack, Token } from '@aws-cdk/core';
 import * as fs from 'fs';
+import * as minimatch from 'minimatch';
 import * as path from 'path';
 
 export interface DockerImageAssetProps extends assets.FingerprintOptions {
@@ -95,6 +96,17 @@ export class DockerImageAsset extends Construct implements assets.IAsset {
       exclude = [...exclude, ...fs.readFileSync(ignore).toString().split('\n').filter(e => !!e)];
     }
 
+    // .dockerignore files allow you to ignore the Dockerfile and .dockerignore file
+    // so that these files do not get sent to the Daemon during COPY or ADD. The
+    // files are still utilized by the Docker daemon, even if they are ignored
+    // We need to copy these files into the asset folder, even if they
+    // are included in the .dockerignore, so that these files can be used during the
+    // docker build, so remove any excludes that would match these two essential files
+    exclude = exclude.filter(ignoreExpression => {
+      return !(minimatch('Dockerfile', ignoreExpression, { dot: true }) ||
+             minimatch('.dockerignore', ignoreExpression, { dot: true }));
+    });
+
     if (props.repositoryName) {
       this.node.addWarning(`DockerImageAsset.repositoryName is deprecated. Override "core.Stack.addDockerImageAsset" to control asset locations`);
     }

packages/@aws-cdk/aws-ecr-assets/package.json

@@ -77,7 +77,8 @@
     "@aws-cdk/aws-lambda": "1.22.0",
     "@aws-cdk/aws-s3": "1.22.0",
     "@aws-cdk/core": "1.22.0",
-    "@aws-cdk/cx-api": "1.22.0"
+    "@aws-cdk/cx-api": "1.22.0",
+    "minimatch": "^3.0.4"
   },
   "homepage": "https://github.com/aws/aws-cdk",
   "peerDependencies": {
@@ -96,10 +97,13 @@
   "engines": {
     "node": ">= 10.3.0"
   },
+  "bundledDependencies": [
+    "minimatch"
+  ],
   "stability": "experimental",
   "awslint": {
     "exclude": [
       "docs-public-apis:@aws-cdk/aws-ecr-assets.DockerImageAssetProps"
     ]
   }
-}
+}

packages/@aws-cdk/aws-ecr-assets/test/dockerignore-image/.dockerignore

@@ -1 +1,3 @@
 foobar.txt
+Dockerfile
+.dockerignore