Serverless-python-requirements: layer: retain: true doesn't seem to work

Created on 30 Aug 2019 · 3Comments · Source: UnitedIncome/serverless-python-requirements

I've started a new package, that is purely to create a lambda layer and upload it - no actual code/functions, only the Layer.

I _think_ I'm supposed to use this kind of syntax:

service: sample-py37
frameworkVersion: ">=1.51.0 <2.0.0"

plugins:
  - serverless-python-requirements

provider:
  name: aws
  runtime: python3.7
  region: us-east-1

custom:
  pythonRequirements:
    dockerizePip: true
    layer:
      retain: true

But it doesn't appear to actually retain the older versions. Am I doing something wrong?

open-for-visibility

Source

miketheman

Most helpful comment

I figured it out, since I had the same issue. What you actually want to do is this:

resources:
  Resources:
    PythonRequirementsLambdaLayer:
      UpdateReplacePolicy: Retain

This will set the layer to retain previous versions of the layer when it updates, preventing your functions that are using the older layer from failing.

NOTE: This does mean you need to externally delete your unused layers or else they will linger.

flyinbutrs on 4 Oct 2019

👍8

All 3 comments

retain: true appears to be an option for the main serverless provider for layers, as opposed to the python-requirements plugin. I'm also curious how to emulate this behavior though.

flyinbutrs on 3 Oct 2019

I figured it out, since I had the same issue. What you actually want to do is this:

resources:
  Resources:
    PythonRequirementsLambdaLayer:
      UpdateReplacePolicy: Retain

This will set the layer to retain previous versions of the layer when it updates, preventing your functions that are using the older layer from failing.

NOTE: This does mean you need to externally delete your unused layers or else they will linger.

flyinbutrs on 4 Oct 2019

👍8

This appears to be an issue in serverless, but we'll keep it open for visibility.