aws-sam-local environment variables

Question

I am following the readme here: https://github.com/awslabs/aws-sam-local

I have a lambda written in python 3.6 and its similar to the helloworld example here : https://g

Answer 1

template file

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Globals:

  Function:
    Timeout: 3

Parameters:

  SomeVar:
    Type: String
    Description: My SomeVar
    Default: default value

Resources:

  HelloWorldFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: hello-world/
      Handler: app.lambdaHandler
      Runtime: nodejs12.x
      Environment:
        Variables:
          SOME_VAR: !Ref SomeVar
      Events:
        HelloWorld:
          Type: Api
          Properties:
            Path: /hello
            Method: get

Outputs:

  HelloWorldApi:
    Description: "API Gateway endpoint URL for Prod stage for Hello World function"
    Value: !Sub "https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/Prod/hello/"

  HelloWorldFunction:
    Description: "Hello World Lambda Function ARN"
    Value: !GetAtt HelloWorldFunction.Arn

  HelloWorldFunctionIamRole:
    Description: "Implicit IAM Role created for Hello World function"
    Value: !GetAtt HelloWorldFunctionRole.Arn

from https://github.com/awslabs/aws-sam-cli/issues/1163#issuecomment-557874976

then in code

console.log(process.env.SOME_VAR);

when you run sam local start-api and it will print default value

when you run sam local start-api --parameter-overrides SomeVar=other_value and it will print other_value

then if you create file env.json with this content

{ "PreviewsFunction": { "SOME_VAR": "123" } }

when you run sam local start-api --env-vars env.json and it will print 123

p.s. it will work with start-api/start-lambda/invoke all in the same way, but it looks like sam deploy only works with --parameter-overrides SomeVar=other_value and no --env-vars