Serverless Plugin External SNS Events

Add ability for functions to use existing or external SNS topics as an event source

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Serverless Plugin: External SNS Events

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What is it?

This is a plugin for the Serverless framework to allow you have a function that uses an already existing, or external (to that service), SNS topic as an event source.

By default, the Serverless SNS event source will create a new topic just for that function, but in many cases if you want a function to subscribe to a topic, the topic will have already been created, either in the same service or in a different service.

How do I use it?

Rather than defining an sns event for your function, define an externalSNS event, where the value is a string, the name of the topic that you want to subscribe this function to.

NOTE: at this time, it is assumed that the topic is in the same account and region as the Lambda function itself. That can be changed in the future if needed - feel free to open an issue, and preferably submit a pull request.

      name: ${self:service}-${self:provider.stage}-doSomething
      handler: src/DoSomething.handler
         - externalSNS: 'some-topic-name'

By doing that, the deploy and remove commands in SLS will now subscribe and unsubscribe your function to or from the specified topic. If you would like to subscribe or unsubscribe the functions manually (outside of a deploy or remove command), you can use serverless subscribeExternalSNS or serverless unsubscribeExternalSNS.

How do I contribute?

Easy! Pull requests are welcome! Just do the following:

  • Clone the code
  • Install the dependencies with npm install
  • Create a feature branch (e.g. git checkout -b my_new_feature)
  • Make your changes and commit them with a reasonable commit message
  • Make sure the code passes our standards with grunt standards
  • Make sure all unit tests pass with npm test

Our goal is 100% unit test coverage, with good and effective tests (it's easy to hit 100% coverage with junk tests, so we differentiate). We will not accept pull requests for new features that do not include unit tests. If you are submitting a pull request to fix a bug, we may accept it without unit tests (we will certainly write our own for that bug), but we strongly encourage you to write a unit test exhibiting the bug, commit that, and then commit a fix in a separate commit. This greatly increases the likelihood that we will accept your pull request and the speed with which we can process it.


This software is released under the MIT license. See the license file for more details.