Understanding Service Accounts

Oct 13, 2025 by talynt.org 9 views

Introduction

Deploying a Ruby on Rails application to Google Cloud Platform (GCP) Cloud Run can be a seamless experience, but it's not uncommon to encounter issues, especially when it comes to authentication and authorization. In this article, we'll delve into the problem of Cloud Run asking for a service account when creating a signed URL in a Ruby on Rails application.

Background

Cloud Run is a fully managed platform that allows you to deploy containerized applications without worrying about the underlying infrastructure. It's a great choice for building scalable and secure applications. However, when it comes to authentication and authorization, things can get a bit tricky.

The Problem

When trying to create a signed URL in a Ruby on Rails application deployed to Cloud Run, you might encounter the following error:

Error: Could not load the default credentials. Browse to https://console.cloud.google.com/projectselector2/iam-admin/serviceaccounts to create one.

This error message indicates that Cloud Run is unable to find a service account to use for authentication. But why is this happening?

Understanding Service Accounts

A service account is a special type of account that belongs to a project and is used to authenticate and authorize services running on Google Cloud Platform. When you deploy an application to Cloud Run, it needs a service account to use for authentication.

Why is Cloud Run Asking for a Service Account?

There are a few reasons why Cloud Run might be asking for a service account:

Lack of Service Account Configuration: If you haven't configured a service account for your Cloud Run service, it will default to using the default service account for the project.
Insufficient Permissions: If the service account doesn't have the necessary permissions to create a signed URL, Cloud Run will ask for a service account.
Missing Credentials: If the service account credentials are missing or invalid, Cloud Run will ask for a service account.

Solving the Problem

To solve this problem, you'll need to configure a service account for your Cloud Run service. Here are the steps:

Step 1: Create a Service Account

Go to the Google Cloud Console and navigate to the IAM & Admin page.
Click on "Service accounts" and then click on "Create service account".
Fill in the required information, such as the service account name and description.
Click on "Create" to create the service account.

Step 2: Generate a Key File

Go to the IAM & Admin page and click on "Service accounts".
Find the service account you created in Step 1 and click on the three vertical dots next to it.
Click on "Create key" and select "JSON key file".
Download the key file and save it securely.

Step 3: Configure the Service Account in Cloud Run

Go to the Cloud Run page and click on the three vertical dots next to your service.
Click on "Edit" and then click on "Service account".
Select the service account you created in Step 1 and click on "Save".

Step 4: Update the Application Code

Update the application code to use the service account credentials.
Use the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to the key file.

Example Code

Here's an example of how to use the service account credentials in a Ruby on Rails application:

# config/environments/production.rb
Rails.application.configure do
  config.active_storage.service = :google_cloud
  config.active_storage.google_cloud.credentials = {
    key: ENV['GOOGLE_APPLICATION_CREDENTIALS']
  }
end

# config/environments/production.rb
Rails.application.configure do
  config.active_storage.service = :google_cloud
  config.active_storage.google_cloud.credentials = {
    key: File.read(Rails.root.join('config', 'service_account_key.json'))
  }
end

Conclusion

In this article, we've explored the problem of Cloud Run asking for a service account when creating a signed URL in a Ruby on Rails application. We've also provided a step-by-step guide on how to configure a service account and update the application code to use the service account credentials.

By following these steps, you should be able to resolve the issue and create signed URLs in your Ruby on Rails application deployed to Cloud Run.

Additional Resources

Google Cloud Run documentation
Google Cloud IAM documentation
Ruby on Rails documentation
Ruby on Rails in Cloud Run Keeps Asking for Service Account: Q&A ===========================================================

Introduction

In our previous article, we explored the problem of Cloud Run asking for a service account when creating a signed URL in a Ruby on Rails application. We also provided a step-by-step guide on how to configure a service account and update the application code to use the service account credentials.

In this article, we'll answer some frequently asked questions (FAQs) related to this topic.

Q&A

Q: What is a service account, and why do I need one?

A: A service account is a special type of account that belongs to a project and is used to authenticate and authorize services running on Google Cloud Platform. You need a service account to use for authentication when creating a signed URL in your Ruby on Rails application deployed to Cloud Run.

Q: How do I create a service account?

A: To create a service account, follow these steps:

Go to the Google Cloud Console and navigate to the IAM & Admin page.
Click on "Service accounts" and then click on "Create service account".
Fill in the required information, such as the service account name and description.
Click on "Create" to create the service account.

Q: What are the permissions required for a service account to create a signed URL?

A: The service account needs to have the following permissions:

cloud.storage.objects.create
cloud.storage.objects.get
cloud.storage.objects.list

Q: How do I generate a key file for my service account?

A: To generate a key file, follow these steps:

Go to the IAM & Admin page and click on "Service accounts".
Find the service account you created and click on the three vertical dots next to it.
Click on "Create key" and select "JSON key file".
Download the key file and save it securely.

Q: How do I configure the service account in Cloud Run?

A: To configure the service account in Cloud Run, follow these steps:

Go to the Cloud Run page and click on the three vertical dots next to your service.
Click on "Edit" and then click on "Service account".
Select the service account you created and click on "Save".

Q: How do I update the application code to use the service account credentials?

A: To update the application code, follow these steps:

Update the config/environments/production.rb file to use the service account credentials.
Use the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to the key file.

Q: What are the benefits of using a service account?

A: Using a service account provides several benefits, including:

Improved security: Service accounts are used for authentication and authorization, which improves the security of your application.
Simplified management: Service accounts can be managed centrally, which simplifies the management of your application.
Better scalability: Service accounts can be used to scale your application, which improves its performance and reliability.

Q: What are the common issues that can occur when using a service account?

A: Some common issues that can occur when using a service account include:

Insufficient permissions: If the service account doesn't have the necessary permissions, it can cause issues.
Missing credentials: If the service account credentials are missing or invalid, it can cause issues.
Configuration errors: If the service account is not configured correctly, it can cause issues.

Conclusion

In this article, we've answered some frequently asked questions related to using a service account with Cloud Run and Ruby on Rails. We hope this article has provided you with a better understanding of the topic and has helped you to resolve any issues you may be experiencing.