NodejsFunction broken on Windows

[misterjoshua]

NodejsFunction doesn't work on Windows. There's some sort of problem with the way it translates Windows paths (backslash) to Docker.

Reproduction Steps

lib/my-stack.ts:

export class MyStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);
    new NodejsFunction(this, 'handler');
  }
}

lib/my-stack.handler.ts:

export const handler = () => 'anything';

Error Log

PS E:\p\break> yarn cdk synth                                                                                                                                                                                                  yarn run v1.22.4
warning package.json: No license field
$ cdk synth
Failed to build file at E:\p\break\lib\my-stack.handler.ts: Error: [Status 125] stdout:


stderr: docker: Error response from daemon: the working directory '\project\lib' is invalid, it needs to be an absolute path.
See 'docker run --help'.
Subprocess exited with error 1
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Environment

• CLI Version : 1.40.0
• Framework Version: 1.40.0
• OS : Windows 10
• Language : TypeScript on NodeJS v12.1.0

---

This is 🐛 Bug Report

[jogold]

The problem is here:

aws-cdk/packages/@aws-cdk/aws-lambda-nodejs/lib/builder.ts

Line 114 in 395c07c

'-w', path.dirname(containerEntryPath),

containerEntryPath is constructed using a path.join() but it should always use forward slashes.

Will open a PR to fix this.