Layer

About Layer

• A Layer here refers to packages that extend beyond the built-in methods of the programming language.
  To simplify: you can think of a layer as similar to Python libraries—you just import them and use them as usual.
  (By default, AWS Lambda functions don’t include external libraries; you must add them through layers).

• Each Lambda function can include up to 5 layers.

• A Lambda function cannot exceed the maximum size limit for layers. If it does, AWS will show a red warning.

• There are two ways to add a layer:
  • Upload directly: zip the original library files and push them to a layer (time-consuming, may cause compatibility issues with Lambda, or risk missing files when zipping).
  • Upload a zipped package directly into the Lambda function.
  • Use existing layers: copy ARNs (from layers others have created) along with the corresponding version.

Reference ARN repository: https://github.com/keithrozario/Klayers