Setup AWS API gateway custom authorizers in serverless framework - amazon-web-services

Question

I need to add AWS API gateway custom authorizer to a Lambda function. Currently I have added the authorizer for each endpoint. As in the following serverless.yml.
serverless.yml
service: test-service
provider:
name: aws
runtime: nodejs6.10
stage: dev
region: us-east-1
functions:
bff:
handler: app.handler
events:
- http:
path: /home
method: get
cors: true
authorizer :
arn: arn:aws:lambda:us-east-1:xxxxxx:function:token-verifier
resultTtlInSeconds: 0
identitySource: method.request.header.Authorization
identityValidationExpression: '.*'
How can I add the custom authorizer to the entire lambda function
rather than adding separately to each endpoint?

Answer 1

You're confusing the boundary between AWS API Gateway and AWS Lambda. It's not your fault. Serverless Framework is that good that it almost blurs those two things.
Strictly speaking, AWS Lambda Functions DO NOT need custom authorizers.
Authorizers are used for securing API Gateway endpoints NOT for AWS Lambda functions.
Therefore, you need to define the authorizer for each endpoint you need to require authorization for.
If you're after making your serverless.yml more concise by not repeating the authorizer definition multiple times, you can define it once and just reference it in your endpoints.
service: test-service
custom:
authorizer:
arn: arn:aws:lambda:us-east-1:xxxxxx:function:token-verifier
resultTtlInSeconds: 0
identitySource: method.request.header.Authorization
identityValidationExpression: '.*'
provider:
name: aws
runtime: nodejs6.10
stage: dev
region: us-east-1
functions:
bff:
handler: app.handler
events:
- http:
path: /home
method: get
cors: true
authorizer: ${self:custom.authorizer}