How to Use Environment Variables in Google Cloud Functions

To use environment variables in a Google Cloud Function, set them during deployment with the --set-env-vars flag or in the Cloud Console. Inside your function code, access these variables using process.env.VARIABLE_NAME in Node.js or the equivalent in other languages.

Syntax

When deploying a Cloud Function, you specify environment variables using the --set-env-vars flag followed by key-value pairs separated by commas.

Inside your function code, access these variables through your language's environment variable access method, such as process.env in Node.js.

bash

gcloud functions deploy FUNCTION_NAME \
  --runtime nodejs18 \
  --trigger-http \
  --set-env-vars KEY1=VALUE1,KEY2=VALUE2

Example

This example shows a Node.js Cloud Function that reads an environment variable named GREETING and returns it in the HTTP response.

javascript

exports.helloEnv = (req, res) => {
  const greeting = process.env.GREETING || 'Hello';
  res.status(200).send(`${greeting}, world!`);
};

Output

Hello, world!

Common Pitfalls

• Not setting environment variables during deployment will cause your function to see undefined values.
• Trying to change environment variables inside the function code does not persist changes.
• Environment variables are case-sensitive; ensure you use the exact key names.

javascript

Wrong way:
exports.func = (req, res) => {
  process.env.MY_VAR = 'new value'; // This does NOT change the env var for future calls
  res.send(process.env.MY_VAR);
};

// Right way:
// Set MY_VAR during deployment with --set-env-vars MY_VAR=value
exports.func = (req, res) => {
  res.send(process.env.MY_VAR);
};

Quick Reference

Remember these tips when using environment variables in Cloud Functions:

• Set variables at deploy time with --set-env-vars.
• Access variables in code via process.env.VAR_NAME (Node.js) or equivalent.
• Do not attempt to modify environment variables inside the function.
• Use environment variables for secrets or config, not for large data.

Key Takeaways

Set environment variables during deployment using the --set-env-vars flag.

Access environment variables inside your function code via process.env in Node.js.

Environment variables are read-only inside the function and cannot be changed at runtime.

Use environment variables for configuration and secrets, not for large or sensitive data storage.

Ensure variable names are case-sensitive and match exactly between deployment and code.