How to Set Environment Variables in Google App Engine

To set environment variables in Google App Engine, add an env_variables section in your app.yaml file with key-value pairs. This works for both standard and flexible environments and allows your app to access these variables at runtime.

Syntax

The env_variables section in app.yaml defines environment variables as key-value pairs. Each key is the variable name, and the value is its string value.

• env_variables: Starts the environment variables block.
• KEY: The name of the environment variable.
• VALUE: The string value assigned to the variable.

yaml

env_variables:
  KEY1: "value1"
  KEY2: "value2"

Example

This example shows how to set two environment variables, API_KEY and ENV, in the app.yaml file. Your application can then read these variables at runtime.

yaml

runtime: python39

env_variables:
  API_KEY: "12345-abcde"
  ENV: "production"

Common Pitfalls

Common mistakes when setting environment variables in App Engine include:

• Not quoting string values, which can cause parsing errors.
• Placing env_variables outside the root level of app.yaml.
• Trying to set environment variables in the flexible environment without redeploying the app.
• Using environment variables for sensitive data without encryption or secret management.

yaml

Wrong:
env_variables:
  API_KEY: 12345-abcde  # Missing quotes can cause issues

Right:
env_variables:
  API_KEY: "12345-abcde"

Quick Reference

Remember these tips when setting environment variables in App Engine:

• Always use quotes around string values.
• Define env_variables at the root level in app.yaml.
• Redeploy your app after changing environment variables.
• Use Google Secret Manager for sensitive data instead of plain environment variables.

Key Takeaways

Set environment variables in the app.yaml file under the env_variables section as key-value pairs.

Always quote string values to avoid parsing errors.

Redeploy your App Engine app after changing environment variables to apply updates.

Avoid storing sensitive data directly in env_variables; use Secret Manager instead.

Place env_variables at the root level of app.yaml for proper recognition.