Serverless deployment to AWS Lambda missing modules?

Question

First time dealing with serverless here. Have successfully deployed using serverless deploy after following the guide to migrating an existing express app over to serverless. But aws lambda keeps throwing an error:

“errorType”: “Runtime.ImportModuleError”, “errorMessage”: “Error: Cannot find module ‘serverless-http’\nRequire stack:\n- /var/task/app.js\n- /var/runtime/UserFunction.js\n- /var/runtime/index.js”,

So I’m confused. What am I doing wrong? The guide to converting an existing express app didn’t say we’d need to create an AWS Lambda Layer, but since it seems like Lambda can’t find the serverless-http module, does it mean that creating a layer is the fix?

Edit: my .zip file seems to only be an express.js file. I'm not sure if that's unusual but reading online reveals that most people seem to have a node_modules folder zipped up as well? I presume the lack of a node_module folder in the .zip file is causing this runtime.ImportModuleError fail? How do I get serverless to add a node_modules folder if that's the case?

Answer 1

node_modules folder is generally packaged with your code -- provided it exists in your directory (does it?).

If node_modules isn't installed on your local machine, then you can create it by using the npm install command. This command will install all the dependencies listed in the package-lock.json file (or package.json) -- sorry I'm not a node guy :(.

But it definitely sounds like you're not uploading your node_modules folder because it's not on your local machine. You have to initialize the directory first.