AWS deployment impossible: non-alphanumeric characters not fully escaped in WebSocket routes

AWS Lambda WebSocket routes not fully escaped in CloudFormation template

Description

When using serverless for deploying AWS Lambda functions, WebSocket routes with multiple instances of the same non-alphanumeric character result in a CloudFormation template validation error on deployment.

1. What did you do?

Added a AWS Lambda function definition to serverless.yml with a WebSocket route with multiple dashes, like the following:

myFunction:
  handler: main.handler
  events:
    - http: POST /some-api-route
    - websocket:
        route: some-api-route

1. What happened?

The command sls deploy fails with the message: Error: The CloudFormation template is invalid: Template format error: Resource name someDashapi-routeWebsocketsRoute is non alphanumeric.

Stack trace:

Error: The CloudFormation template is invalid: Template format error: Resource name someDashapi-routeWebsocketsRoute is non alphanumeric.
      at provider.request.catch.error (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:20:13)
      at tryCatcher (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/util.js:16:23)
      at Promise._settlePromiseFromHandler (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:547:31)
      at Promise._settlePromise (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:604:18)
      at Promise._settlePromise0 (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:649:10)
      at Promise._settlePromises (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:725:18)
      at _drainQueueStep (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:93:12)
      at _drainQueue (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:86:9)
      at Async._drainQueues (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:102:5)
      at Immediate.Async.drainQueues (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:15:14)
      at runCallback (timers.js:794:20)
      at tryOnImmediate (timers.js:752:5)
      at processImmediate [as _immediateCallback] (timers.js:729:5)

This template works when running locally with the serverless offline plugin.

1. What should’ve happened?

The deployment should have run successfully.

1. What’s the content of your serverless.yml file?

service: my-service

provider:
  name: aws
  runtime: python3.6
  stage: dev
  region: eu-west-1
  deploymentBucket:
    name: deploymentBucket
  websocketsApiRouteSelectionExpression: $request.body.action

functions:
  myFunction:
    handler: main.handler
    events:
      - http: POST /some-api-route
      - websocket:
          route: some-api-route

1. What’s the output you get when you use the SLS_DEBUG=* environment variable (e.g. SLS_DEBUG=* serverless deploy)

  Error --------------------------------------------------
 
  Error: The CloudFormation template is invalid: Template format error: Resource name someDashapi-routeWebsocketsRoute is non alphanumeric.
      at provider.request.catch.error (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:20:13)
  From previous event:
      at AwsDeploy.validateTemplate (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/lib/validateTemplate.js:16:85)
  From previous event:
      at AwsDeploy.BbPromise.bind.then (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:119:39)
  From previous event:
      at Object.aws:deploy:deploy:validateTemplate [as hook] (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:115:30)
      at BbPromise.reduce (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:55)
  From previous event:
      at PluginManager.invoke (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:22)
      at PluginManager.spawn (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:510:17)
      at AwsDeploy.BbPromise.bind.then (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:93:48)
  From previous event:
      at Object.deploy:deploy [as hook] (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:89:30)
      at BbPromise.reduce (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:55)
  From previous event:
      at PluginManager.invoke (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:22)
      at getHooks.reduce.then (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:525:24)
  From previous event:
      at PluginManager.run (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:525:8)
      at variables.populateService.then (/usr/local/lib/node_modules/serverless/lib/Serverless.js:133:33)
      at runCallback (timers.js:794:20)
      at tryOnImmediate (timers.js:752:5)
      at processImmediate [as _immediateCallback] (timers.js:729:5)
  From previous event:
      at Serverless.run (/usr/local/lib/node_modules/serverless/lib/Serverless.js:120:74)
      at serverless.init.then (/usr/local/lib/node_modules/serverless/bin/serverless.js:75:30)
      at /usr/local/lib/node_modules/serverless/node_modules/graceful-fs/graceful-fs.js:111:16
      at /usr/local/lib/node_modules/serverless/node_modules/graceful-fs/graceful-fs.js:45:10
      at FSReqWrap.oncomplete (fs.js:135:15)
  From previous event:
      at initializeErrorReporter.then (/usr/local/lib/node_modules/serverless/bin/serverless.js:75:8)
      at runCallback (timers.js:794:20)
      at tryOnImmediate (timers.js:752:5)
      at processImmediate [as _immediateCallback] (timers.js:729:5)
  From previous event:
      at Object.<anonymous> (/usr/local/lib/node_modules/serverless/bin/serverless.js:64:4)
      at Module._compile (module.js:652:30)
      at Object.Module._extensions..js (module.js:663:10)
      at Module.load (module.js:565:32)
      at tryModuleLoad (module.js:505:12)
      at Function.Module._load (module.js:497:3)
      at Function.Module.runMain (module.js:693:10)
      at startup (bootstrap_node.js:188:16)
      at bootstrap_node.js:609:3
 
  Get Support --------------------------------------------
     Docs:          docs.serverless.com
     Bugs:          github.com/serverless/serverless/issues
     Issues:        forum.serverless.com
 
  Your Environment Information ---------------------------
     Operating System:          linux
     Node Version:              8.10.0
     Framework Version:         1.60.5
     Plugin Version:            3.2.7
     SDK Version:               2.2.1
     Components Core Version:   1.1.2
     Components CLI Version:    1.4.0

Suggested Potential Fix

The following code in lib/plugins/aws/lib/naming.js appears to be the culprit:

getNormalizedWebsocketsRouteKey(route) {
    return route
      .replace('$', 'S') // dollar sign
      .replace('/', 'Slash')
      .replace('-', 'Dash')
      .replace('_', 'Underscore')
      .replace('.', 'Period');
  },

Proposed change:

getNormalizedWebsocketsRouteKey(route) {
    return route
      .replace(/\$/g, 'S') // dollar sign
      .replace(/\//g, 'Slash')
      .replace(/-/g, 'Dash')
      .replace(/_/g, 'Underscore')
      .replace(/\./g, 'Period');
  },

Proposed unit tests (lib/plugins/aws/lib/naming.test.js), under the describe('#getNormalizedWebsocketsRouteKey()') section at line 252:

it('converts multiple `-` correctly', () => {
    expect(sdk.naming.getNormalizedWebsocketsRouteKey('a-longer-path')).to.equal('aDashlongerDashpath');
});

it('converts multiple `-` and `_` correctly', () => {
    expect(sdk.naming.getNormalizedWebsocketsRouteKey('a-long_er-path_still')).to.equal('aDashlongUnderscoreerDashpathUnderscorestill');
});

[tom-marsh]

Apologies for the delay, see above for the pull request.

[medikoo]

@tom-marsh indeed normalization logic is broken as you point (sorry I missed your point in initial description).

PR that fixes that is definitely welcome!