When and how to use Application default credentials for Google API auth, with example scripts to set them up and example code to consume them
In my recent post, ‘The Eject Button‘, I explored the idea of writing Apps Script code that can be easily moved to other environments like Google Cloud. This was inspired by the seamless local development workflows available in other languages, which begs the question: how can Apps Script developers replicate that experience?
A big piece of that puzzle is authentication. How do you securely test code on your local machine that needs to talk to Google APIs?
Google Workspace Developer Expert Bruce Mcpherson provides the answer in his excellent guide, ‘Application Default Credentials with Google Cloud and Workspace APIs‘. His post is the perfect starting point for any developer looking to streamline their workflow. The key takeaway is that by using the Google Cloud CLI, your local code can securely use your own credentials to access Google APIs.
When you combine ADC for authenticating real API calls with his gas-fakes mocking library for simulating Apps Script services, you have a powerful toolkit that brings a professional development cycle to the Apps Script world.
If you’re looking to level up your skills and knowledge, I highly recommend diving into Bruce’s article.
