Cannot run both Node and Python offline runtimes simultaneously

[lebolo]

Bug Report

Current Behavior
Running serverless offline with both Node and Python runtimes gives the following error when hitting a Python endpoint:

Traceback (most recent call last):
  File "/foo/node_modules/serverless-offline/dist/lambda/handler-runner/python-runner/invoke.py", line 76, in <module>
    module = import_module(args.handler_path.replace(os.sep, '.'))
  File "/foo/venv/lib/python3.6/importlib/__init__.py", line 121, in import_module
    raise TypeError(msg.format(name))
TypeError: the 'package' argument is required to perform a relative import for '.webpack.service.src.utilsPy'

Sample Code

• file: serverless.yml

service  :
  name: ${self:custom.serviceName}
custom   :
  packageJson       : ${file(./package.json)}
  serviceName       : ${self:custom.packageJson.name}
  webpack           :
    webpackConfig : ./webpack.config.js
    includeModules: true
  serverless-offline:
    httpPort: 4000
  pythonRequirements:
    dockerizePip: true
plugins:
  - serverless-webpack
  - serverless-offline
  - serverless-pseudo-parameters
  - serverless-python-requirements
provider :
  name              : aws
  runtime           : nodejs12.x
  <removed a bunch of parameters not relevant to this>
functions:
 - ${file(some-other-file-not-relevant.yml)}
  - health:
      name       : ${self:service}-${self:provider.stage}-health
      description: Health check endpoint
      handler    : src/utils.handler
      memorySize : 128
      timeout    : 10
      events     :
        - http:
            path  : /health
            method: GET
            cors  : true
  - health-py:
      name       : ${self:service}-${self:provider.stage}-health-py
      runtime    : python3.6
      description: Health check endpoint for python
      handler    : src/utilsPy.handler
      memorySize : 128
      timeout    : 10
      events     :
        - http:
            path  : /health-py
            method: GET
            cors  : true

• file: webpack.config.js

const path = require('path');
const slsw = require('serverless-webpack');
const nodeExternals = require('webpack-node-externals');
const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');

// CUSTOM CODE: Remove Python files as entry points
const entries = {};
Object.keys(slsw.lib.entries).forEach(
    key => {
      if (!slsw.lib.entries[key].match(/\.py$/)) {
        entries[key] = [slsw.lib.entries[key]]
      }
    }
);

module.exports = {
  context: __dirname,
  mode: slsw.lib.webpack.isLocal ? 'development' : 'production',
  entry: entries, // CUSTOM CODE: Uses custom entry above
  devtool: slsw.lib.webpack.isLocal ? 'cheap-module-eval-source-map' : 'source-map',
  resolve: {
    extensions: ['.mjs', '.json', '.ts'],
    symlinks: false,
    cacheWithContext: false,
  },
  output: {
    libraryTarget: 'commonjs',
    path: path.join(__dirname, '.webpack'),
    filename: '[name].js',
  },
  target: 'node',
  externals: [nodeExternals()],
  module: {
    rules: [
      // all files with a `.ts` or `.tsx` extension will be handled by `ts-loader`
      {
        test: /\.(tsx?)$/,
        loader: 'ts-loader',
        exclude: [
          [
            path.resolve(__dirname, 'node_modules'),
            path.resolve(__dirname, '.serverless'),
            path.resolve(__dirname, '.webpack'),
          ],
        ],
        options: {
          transpileOnly: true,
          experimentalWatchApi: true,
        },
      },
    ],
  },
  plugins: [
    // new ForkTsCheckerWebpackPlugin({
    //   eslint: true,
    //   eslintOptions: {
    //     cache: true
    //   }
    // })
  ],
};

• file: utils.ts

import { APIGatewayProxyHandler } from 'aws-lambda';
import 'source-map-support/register';
/**
 * A simle health check endpoint...
 * @param event
 * @param _context
 */
export const handler: APIGatewayProxyHandler = async (event, _context) => {
    return {
        statusCode: 200,
        body: JSON.stringify({
            message: 'Healthy!',
            input: event,
        }, null, 2),
    };
};

• file: utilsPy.py

"""
    A simple health checkpoint for python
"""
import json
def handler(event, context):
    return {
            'statusCode': 200,
            'body':
            json.dumps({
              'message':'Healthy Python!',
              'input': event
              })
            }

Expected behavior/code
Expecting to run both TypeScript and Python lambdas offline simultaneously.

Environment

• serverless version: 1.71.3
• serverless-offline version: 6.2.0
• node.js version: 12.6.2
• OS: macOS 10.14.6

optional, if you are using any of the following frameworks to invoke handlers

• python version: 3.6

Additional context/Screenshots

When I run serverless offline, I am able to successfully go to the health endpoint (javascript), but going to the health-py endpoint gives me the error pasted above.

If I instead run serverless offline --location ., I am able to successfully go to the health-py endpoint, but the health endpoint gives me this error

Failure: Cannot find module '/foo/src/utils'

Require stack:
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/InProcessRunner.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/index.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/HandlerRunner.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/index.js
- /foo/node_modules/serverless-offline/dist/lambda/LambdaFunction.js
- /foo/node_modules/serverless-offline/dist/lambda/LambdaFunctionPool.js
- /foo/node_modules/serverless-offline/dist/lambda/Lambda.js
- /foo/node_modules/serverless-offline/dist/lambda/index.js
- /foo/node_modules/serverless-offline/dist/ServerlessOffline.js
- /foo/node_modules/serverless-offline/dist/index.js
- /foo/node_modules/serverless-offline/dist/main.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/classes/PluginManager.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/Serverless.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/utils/autocomplete.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/bin/serverless.js
Error: Cannot find module '/foo/src/utils'
Require stack:
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/InProcessRunner.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/index.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/HandlerRunner.js
- /foo/node_modules/serverless-offline/dist/lambda/handler-runner/index.js
- /foo/node_modules/serverless-offline/dist/lambda/LambdaFunction.js
- /foo/node_modules/serverless-offline/dist/lambda/LambdaFunctionPool.js
- /foo/node_modules/serverless-offline/dist/lambda/Lambda.js
- /foo/node_modules/serverless-offline/dist/lambda/index.js
- /foo/node_modules/serverless-offline/dist/ServerlessOffline.js
- /foo/node_modules/serverless-offline/dist/index.js
- /foo/node_modules/serverless-offline/dist/main.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/classes/PluginManager.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/Serverless.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/lib/utils/autocomplete.js
- /bar/.nave/installed/bender-sls/lib/node_modules/serverless/bin/serverless.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:980:15)
    at Function.resolve (internal/modules/cjs/helpers.js:83:19)
    at InProcessRunner.run (/foo/node_modules/serverless-offline/dist/lambda/handler-runner/in-process-runner/InProcessRunner.js:59:18)
    at HandlerRunner.run (/foo/node_modules/serverless-offline/dist/lambda/handler-runner/HandlerRunner.js:148:64)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at LambdaFunction.runHandler (/foo/node_modules/serverless-offline/dist/lambda/LambdaFunction.js:313:20)
    at hapiHandler (/foo/node_modules/serverless-offline/dist/events/http/HttpServer.js:463:18)
    at module.exports.internals.Manager.execute (/foo/node_modules/@hapi/hapi/lib/toolkit.js:45:28)
    at Object.internals.handler (/foo/node_modules/@hapi/hapi/lib/handler.js:46:20)
    at exports.execute (/foo/node_modules/@hapi/hapi/lib/handler.js:31:20)
    at Request._lifecycle (/foo/node_modules/@hapi/hapi/lib/request.js:312:32)
    at Request._execute (/foo/node_modules/@hapi/hapi/lib/request.js:221:9)

[barnc]

Running into this same exact issue. Did you ever find a solution to this?

[lebolo]

We did not. We ended up only using Python lambdas for this project =\

[garymcleanhall]

The problem is that the webpack output directory is prefixed with a period . - this makes python think that the import is package-relative, yet no package has been specified.

To fix, have webpack output everything to a directory without the . prefix:

output: {
    libraryTarget: 'commonjs',
    path: path.join(__dirname, 'dist'),
    filename: '[name].js',
  },

[hongquan]

Our project doesn't have NodeJS, but we also ran into this error, at the same line:

module = import_module(args.handler_path.replace(os.sep, '.'))

We managed to fork serverless-offline and added a fix. But we are not sure if this solves other people's problem as well. In our case, the args.handler_path has a crazy path like ../../../../../../tmp/serverless-offline/services/ekyc-api/pykye/ckkg9e51y0002e8l113qz4f13/code/pykye.serverless, and when looking into that path, we don't see our code (pykye.serverless) copied to there. So our fix is just to let python-runner import the code right at project source folder, instead of in /tmp/ path.

[raytorres280]

I get the error even though on deploy my code works.

I can deploy my zip file using sls deploy and can hit the endpoint without error. Locally, using sls offline or sls offline --location . I get the same package argument error.

edit: It would be great if we could provide an artifact to sls offline the same way we do to serverless