How to get started with Google Cloud Client Libraries

Key Takeaways

Cloud client libraries. In the last episode, I talked about what they are and why they're so useful. I told you about how they significantly reduce the code that you need to write and handle all those low-level details like authentication. Now, [music] let's get a little bit more hands-on. We're going to set up an environment, get application default credentials configured, [music] and make our very first cloud client library call. This is what's what with cloud client libraries. If you're developing with Google Cloud on your local machine, you'll need to install the Google Cloud CLI or G-Cloud before you can access Google Cloud services. The Google Cloud CLI is part of the Google Cloud SDK. Not only does it let you manage Google Cloud resources from your terminal, it also handles authentication for your locally running application code. The instructions for installing the Google Cloud CLI vary by operating system, so I've linked instructions in the description. For the demonstration I'm about to walk through, I already have the CLI installed, just not configured. So, I've got a cloud storage bucket and I want to return a list of all the files that I have stored in it. Here's how I can do that with Python. Now, before I can run this, I'll install the dependencies with pip install. Rather than a single massive library, Google Cloud client libraries are split by service. Since I'm accessing Google Cloud Storage, I'll install the corresponding client library, Google Cloud Storage. You'll see this pattern for most of the services. Google Cloud compute, Google Cloud Secret Manager, and so on. This approach means you'll only install the code that you need, keeping your application light and clean. Let me do a quick rundown of the code here. First, I import the library for Google Cloud Storage. Next, I instantiate the client. The client is the main entry point for any subsequent calls to the API that I make in my application code. After that, I construct a request which in this case only requires the name of my GCS bucket as a resource path. And now the magic happens. The request is sent to Google Cloud using the list objects method of my client. And since the results are returned as an iterable object, I have a loop to simply print out the name of each object in my bucket. I'm going to run this now just to show you what happens. Like I mentioned before, I installed the Google Cloud CLI, but I haven't configured it. So, as expected, I get an authentication error. Our application doesn't know anything about who I am and what it's allowed to do on Google Cloud. To fix this, I need to get application default credentials or ADC for short. Application default credentials are a standard automatic way for your application to find the right permissions to talk to Google Cloud APIs. There are a few ways to provide your application with these credentials, but for local development, I'll show you the most straightforward approach. Run g-cloud o application-default login. This command opens a browser for you to sign in with your Google account and then creates a local credential file in a well-known location on your file system. You might receive a message like this one warning you about a missing quota project. Well, the quota project is a Google Cloud project that is responsible for billing and usage limits of an API call. I'll talk more about quota projects in a later video. This particular example doesn't need one. So, I'm going to keep going and run the code. Notice again that when we create the client, we don't explicitly provide any credentials. This is the magic of application default credentials. My code will automatically find the credentials I just set up and use them to authenticate to Google Cloud. And there we go. Now that I'm authenticated with my application default credentials, the code runs and I've got a list of my files right here. I didn't have to change a single line of my Python code to indicate credentials or other authentication details. With a single G-Cloud command, I configured my local environment and the client library automatically picked it up. That's the power of this approach. Now this is a very brief overview of how to get started with cloud client libraries with a very simple example as a preferred way of providing authentication to cloud client libraries. Application default credentials are an important [music] concept to understand. There's more to talk about there. So catch the next episode while I'll cover where your application is looking for those credentials, what they look like, and more. And as always, if you have any questions, feel free to drop them in the comments. Thanks for [music] watching. See you next time. Heat. Heat.