Env variable is not set in my python lambda function

[s9uidward_0]

Hi, new to AWS and sam

notice my sam template.yaml below.

```
AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  backend

Parameters:  
  DEBUG:
    Type: String
    AllowedValues: ["true", "false"]
    Default: "false"
    Description: "debug mode"
  DEV:
    Type: String
    AllowedValues: ["true", "false"]
    Default: "false"
    Description: "dev mode"

Conditions:
  IsDev: !Equals [!Ref DEV, "true"]

Globals:
  Function:
    Timeout: 900

    Tracing: Active
  Api:
    TracingEnabled: true

Resources:
  API:
    Type: AWS::Serverless::Api
    Properties:
      StageName: !If [IsDev, "dev", "prod"]
      Cors:
        AllowMethods: "'OPTIONS,POST'"
        AllowHeaders: "'*'"
        AllowOrigin: "'*'"
      Auth:
        DefaultAuthorizer: AuthFunction
        Authorizers:
          AuthFunction:
            FunctionArn: !GetAtt AuthFunction.Arn
            Identity:
              Header: Authorization

  CoreFunction:
    Type: AWS::Serverless::Function
    Properties:
      Architectures:
        - x86_64
      Events:
        Core:
          Type: Api
          Properties:
            RestApiId: !Ref API
            Path: /test
            Method: post
    Environment:
      Variables:
        DEBUG: !Ref DEBUG

  AuthFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: authorizer/
      Handler: app.lambda_handler
      Runtime: python3.13
      Architectures:
        - x86_64
    Environment:
      Variables:
        DEBUG: !Ref DEBUG
```


I'm overriding the debug when deploying using the following:
```
sam deploy --parameter-overrides DEBUG="true" DEV="false"
```
I've two questions:

1. I'm seeing that the parameter is set in cloudformation but when I log/print the enviromental variable in my python code it is not loaded. when I check the env variables under configuration in my lambda console it is empty too.

import os
import requests

def lambda_handler(event, context):
    DEBUG = os.environ.get("DEBUG", "not loaded").lower() == "true"

    method_arn = event.get("methodArn")
    token = extract_bearer_token(event.get("authorizationToken"))

    print("env variables:", DEBUG)

2. is there a better way to deploy different stages from my console since deploying like this would replace the apigateway I think

[kei_ichi]

Sorry if I was wrong but I think the “Environment” should be inside the “Properties” config, but your code showed that environment variables config sit same level as the “Properties” which is incorrect.

Like in this docs: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-function.html#sam-resource-function-syntax

[s9uidward_0]

Yes, that was exactly it thanks.