Where does zappa upload environment variables to?

Question

tl;dr

Environment variables set in a zappa_settings.json don't upload as environment variables to AWS Lambda. Where do they go?

ts;wm

I have a Lambda function configured, deployed and managed using the Zappa framework. In the zappa_settings.json I have set a number of environment variables. These variables are definitely present as my application successfully runs however, when trying to inspect the Lambda function environment variables in the console or AWS CLI I see no environment variables have been uploaded to the Lambda function itself.

Extract from zappa_settings.json:

{
  "stage-dev": {
    "app_function": "project.app",
    "project_name": "my-project",
    "runtime": "python3.7",
    "s3_bucket": "my-project-zappa",
    "slim_handler": true,
    "environment_variables": {
      "SECRET": "mysecretvalue"
    }
  }
}

Output of aws lambda get-function-configuration --function-name my-project-stage-dev:

{
  "Configuration": {
    "FunctionName": "my-project-stage-dev",
    "FunctionArn": "arn:aws:lambda:eu-west-1:000000000000:function:my-project-stage-dev",
    "Runtime": "python3.7",
    "Role": "arn:aws:iam::000000000000:role/lambda-execution-role",
    "Handler": "handler.lambda_handler",
    "CodeSize": 12333025,
    "Description": "Zappa Deployment",
    "Timeout": 30,
    "MemorySize": 512,
    "LastModified": "...",
    "CodeSha256": "...",
    "Version": "$LATEST",
    "TracingConfig": {
      "Mode": "PassThrough"
    },
    "RevisionId": "..."
  },
  "Code": {
    "RepositoryType": "S3",
    "Location": "..."
  }
}

Environment is absent from the output despite being included in the zappa_settings and the AWS documentation indicating it should be included if present, this is confirmed by checking in the console. I want to know where zappa is uploading the environment variables to, and if possible why it is doing so over using Lambda's in-built environment?

AWS CLI docs: https://docs.aws.amazon.com/cli/latest/reference/lambda/get-function-configuration.html

Answer 1

environment_variables are saved in zappa_settings.py when creating a package for deployment (run zappa package STAGE and explore the archive) and are then dynamically set as environment variables by modifying os.environ in handler.py.

To set native AWS variables you need to use aws_environment_variables.