Serverless SAM Export Error: Cannot read property 'charAt' of undefined

[marianina8]

When I run the following command:

serverless sam export --output ./sam-template.yml

I get the following error:

      Type Error ---------------------------------------------

    Cannot read property 'charAt' of undefined

        For debugging logs, run again after setting the "SLS_DEBUG=*" environment variable.

    Stack Trace --------------------------------------------

    TypeError: Cannot read property 'charAt' of undefined
        at StreamEventConverter.convertEvent (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/events/StreamEventConverter.js:29:33)
        at Object.keys.forEach (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/FunctionConverter.js:101:49)
        at Array.forEach (<anonymous>)
        at serverlessFunction.events.forEach (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/FunctionConverter.js:95:33)
        at Array.forEach (<anonymous>)
        at FunctionConverter.serverlessFunctionToSam (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/FunctionConverter.js:89:33)
        at allFunctions.forEach (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/SamGenerator.js:119:32)
        at Array.forEach (<anonymous>)
        at SamGenerator.readFunctions (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/SamGenerator.js:109:20)
        at SamGenerator.generate (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/lib/SamGenerator.js:58:10)
        at BbPromise (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/index.js:206:46)
        at SamPlugin.exportSam (/Users/marian/goop/src/github.com/goop/service-wms/node_modules/serverless-sam/index.js:203:12)
    From previous event:
        at PluginManager.invoke (/Users/marian/.nvm/versions/node/v10.9.0/lib/node_modules/serverless/lib/classes/PluginManager.js:390:22)
        at PluginManager.run (/Users/marian/.nvm/versions/node/v10.9.0/lib/node_modules/serverless/lib/classes/PluginManager.js:421:17)
        at variables.populateService.then.then (/Users/marian/.nvm/versions/node/v10.9.0/lib/node_modules/serverless/lib/Serverless.js:157:33)
        at runCallback (timers.js:693:18)
        at tryOnImmediate (timers.js:664:5)
        at processImmediate (timers.js:646:5)
        at process.topLevelDomainCallback (domain.js:121:23)
    From previous event:
        at Serverless.run (/Users/marian/.nvm/versions/node/v10.9.0/lib/node_modules/serverless/lib/Serverless.js:144:8)
        at serverless.init.then (/Users/marian/.nvm/versions/node/v10.9.0/lib/node_modules/serverless/bin/serverless:43:50)

I'm using serverless v.1.30.3 and node v10.9 I'm not quite sure where to start with this error message as searching online has not yielded any similar issues/fixes. Any pointers would be greatly appreciated!

[marianina8]

Just a follow up, I was able to get it to work by changing my serverless.yml file's declaration of a stream from:

    events:
      - stream: ${env:arn}

to:

    events:
      - stream:
          arn: ${env:arn}
          type: dynamodb

(* arn is stored as an environment variable). For some reason I didn't see any documentation that suggests that this is how streams should be defined. To your knowledge is this the correct way to define a stream in serverless.yml? It seemed to work deploying to AWS Lambda even the original way. Thanks!

[xevenheaven]

Just to chime in, I was facing a similar problem:

  Type Error ---------------------------------------------

  Cannot read property 'charAt' of undefined

     For debugging logs, run again after setting the "SLS_DEBUG=*" environment variable.

  Your Environment Information -----------------------------
     OS:                     darwin
     Node Version:           10.11.0
     Serverless Version:     1.36.3

My serverless.yml was:

    events:
      - stream:
          arn: "arn:aws:kinesis:${region}:${account}:stream/${name}"
          batchSize: 100
          startingPosition: LATEST
          enabled: true

Following @marianina8's method, I added the type field:

    events:
      - stream:
          arn: "arn:aws:kinesis:${region}:${account}:stream/${name}"
          batchSize: 100
          startingPosition: LATEST
          enabled: true
          type: kinesis

And that solved the problem.

ℹ️Might wanna add in the docs that the type field is required.