No matching handler found for 'handler'. Check your service definition

I just upgraded from serverless-webpack 2.0.0 to 2.2.0 and got the following error. It was working perfectly with the previous version.

No matching handler found for 'handler'. Check your service definition

Is there anything wrong in my configuration?

service: my_service

provider:
  ...

custom:
  webpack: webpack.config.serverless.js

functions:
  my_function:
    handler: handler.my_function
    events:
       ...

plugins:
  - serverless-webpack

FYI I’m on serverless latest (as of today: 1.18.1)

[vcarel]

Ok, found. The problem is that slsw.lib.entries does not contain an array, but the object { 'src/server/handler': './src/server/handler.js' }

If I just use the previous config, it works fine

module.exports = {
  entry: ['./src/server/handler.js']

So, at the end, the fix was to set the path in the handler definition:

functions:
  my_function:
    handler: src/server/handler.my_function

[HyperBrain]

Ok. I think the missing path in the function definition is the problem. The function definition should define the path - otherwise you’d also get issues with other plugins that need to find the handler. The problem is, that Serverless (the framework) is completely unaware of the handler location in your case.

So, please change the handler definition in your serverless.yml.

… and the good thing: With 2.2.0 you now do not have to set the entries manually anymore in your webpack config. Just use:

// webpack.conf.js
const slsw = require('serverless-webpack');
module.exports = {
  entry: slsw.lib.entries,
  ...
  output: {
    ...
    filename: '[name].js',
    ...
  }
};

Then you can add functions to your service without changing the config again.