Set environment variables from external file in serverless.yml

Question

I'm using serverless and serverless-local for local development.

I've got an external file which holds references to environment variables which I retrieve from node.env in my app.

From what I understand, I should be able to set my environment variables such as

dev:
   AWS_KEY: 'key',
   SECRET: 'secret
test:
   AWS_KEY: 'test-key',
   SECRET: 'test-secret',
etc:
   ...

and have those environment variables included in my app through the following line in my serverless.yml

provider:
  name: aws
  runtime: nodejs4.3
  stage: ${opt:stage, self:custom.default_stage}
  deploymentBucket: serverless-deploy-packages/${opt:stage, self:custom.default_stage}
  environment: 
    ${file(./serverless-env.yml):${opt:stage, self:custom.default_stage}}

then in the commandline, I call

serverless offline --stage dev --port 9000

I thought this would include the correct vars in my app, but it isn't working. Is this not how it is supposed to work? Am I doing something wrong here?

Answer 1

This is how you can separate your environments by different stages:

serverless.yml:

custom:
  test:
    project: xxx
  prod:
    project: yyy

provider:
  ...
  stage: ${opt:stage, 'test'}
  project: ${self:custom.${opt:stage, 'test'}.project}
  environment:
    ${file(.env.${opt:stage, 'test'}.yml):}

package:
  exclude:
    - .env.*

.env.test.yml:

VARIABLE1: value1
VARIABLE2: value2

During deploy, pass --stage=prod or skip and test project will be deployed. Then in your JS code you can access ENV variables with process.env.VARIABLE1.

Answer 2

From docs:

You can set the contents of an external file into a variable:

file: ${file(./serverless-env.yml)}

And later you can use this new variable to access the file variables.

secret: file.dev.SECRET

Or you can use the file directly:

secret: ${file(./serverless-env.yml):dev.SECRET}