Serverless Layers

• Automatically attaches layers to the provider and for each function
  • Skips functions with no other layers as they will use the layer(s) we added to the provider
• Creates a new layer's version when dependencies are updated
• Does not publish a new layer if dependencies are unchanged
• Drastically reduces lambda size
• Reduces deployment time
• Allows sharing of the same layers (libraries) among all lambda functions

Options

• NodeJS
• Ruby
• Python

Common Requirements

• AWS only (sorry)
• Serverless >= 1.34.0 (layers support)

Install

npm install -D serverless-layers

or

serverless plugin install --name serverless-layers

Add the plugin to your serverless.yml file:

Single layer config

Example:

plugins:
  - serverless-layers

custom:
  serverless-layers:
    functions: # optional
      - my_func2
    dependenciesPath: ./package.json

functions:
  my_func1:
    handler: handler.hello
  my_func2:
    handler: handler.hello

Multiple layers config

Example:

plugins:
  - serverless-layers

custom:
  serverless-layers:
    # applies for all lambdas 
    - common:
        dependenciesPath: ./my-folder/package.json
    # apply for foo only
    - foo:
        functions:
          - foo
        dependenciesPath: my-folder/package-foo.json
    - staticArn:
        functions:
          - foo
          - bar
        arn: arn:aws:lambda:us-east-1:<your_account>:layer:node-v13-11-0:5

functions:
  foo:
    handler: handler.hello
  bar:
    handler: handler.hello

NodeJS

Requirements

• Node >= v6.10.3
• NPM >= 3.10.10
• A valid package.json file

Options

Ruby

Requirements

• Ruby >= 2.5
• A valid Gemfile file

Options

Python

Requirements

• Python >= 2.7
• A valid requirements.txt file

Options

Default Serverless Setup

This plugin will set up the following options automatically if not specified in serverless.yml.

Minimal Policy permissions for CI/CD IAM users

serverless-layers-policy.json

{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Action":[
            "s3:PutObject",
            "s3:GetObject"
         ],
         "Resource": "arn:aws:s3:::examplebucket"
      },
      {
         "Effect":"Allow",
         "Action":[
            "cloudformation:DescribeStacks"
         ],
         "Resource": "*"
      },
      {
         "Effect":"Allow",
         "Action":[
            "lambda:PublishLayerVersion"
         ],
         "Resource": "*"
      }
   ]
}

License

MIT

Contributors

Yes, thank you! This plugin is community-driven, and most of its features are from different authors. Please update the docs and tests and add your name to the package.json file. We try to follow Airbnb's JavaScript Style Guide.

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