--- title: Instrumenting a Ruby Cloud Run Function description: Datadog, the leading service for cloud-scale monitoring. breadcrumbs: >- Docs > Serverless > Google Cloud Run > Instrumenting Cloud Run Functions > Instrumenting a Ruby Cloud Run Function --- # Instrumenting a Ruby Cloud Run Function {% alert level="info" %} A sample application is [available on GitHub](https://github.com/DataDog/serverless-gcp-sample-apps/tree/main/cloud-run/sidecar/ruby). {% /alert %} ## Setup{% #setup %} 1. **Install the Datadog Ruby tracer**. Add the `datadog` gem to your Gemfile: ``` source 'https://rubygems.org' gem 'datadog' ``` See [Tracing Ruby applications](https://docs.datadoghq.com/tracing/trace_collection/automatic_instrumentation/dd_libraries/ruby/#instrument-your-application) for additional information on how to configure the tracer and enable auto instrumentation. 1. **Install serverless-init as a sidecar**. {% tab title="Datadog CLI" %} Setup: Install the Datadog CLI ```shell npm install -g @datadog/datadog-ci @datadog/datadog-ci-plugin-cloud-run ``` Install the [gcloud CLI](https://cloud.google.com/sdk/docs/install) and authenticate with `gcloud auth login`. Configuration: Configure the [Datadog site](https://docs.datadoghq.com/getting_started/site/) and Datadog API key, and define the service name to use in Datadog. ```shell export DATADOG_SITE="" export DD_API_KEY="" export DD_SERVICE="" ``` Instrument: If you are new to Datadog serverless monitoring, launch the Datadog CLI in interactive mode to guide your first installation for a quick start. ```shell datadog-ci cloud-run instrument -i ``` To set up the Datadog sidecar for your applications, run the `instrument` command *after* your normal deployment. You can specify multiple services to instrument by passing multiple `--service` flags. ```shell datadog-ci cloud-run instrument --project --service --region ``` You can pin to a specific image with the `--sidecar-image` flag. See the [latest releases on Docker Hub](https://hub.docker.com/r/datadog/serverless-init). Additional parameters can be found in the [CLI documentation](https://github.com/DataDog/datadog-ci/tree/master/packages/plugin-cloud-run#arguments). {% /tab %} {% tab title="Terraform" %} The [Datadog Terraform module for Google Cloud Run](https://github.com/DataDog/terraform-google-cloud-run-datadog) wraps the [`google_cloud_run_v2_service`](https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/cloud_run_v2_service) resource and automatically configures your Cloud Run app for Datadog Serverless Monitoring by adding required environment variables and the serverless-init sidecar. If you don't already have Terraform set up, [install Terraform](https://developer.hashicorp.com/terraform/install), create a new directory, and make a file called `main.tf`. Then, add the following to your Terraform configuration, updating it as necessary based on your needs: ```tf variable "datadog_api_key" { description = "Your Datadog API key" type = string sensitive = true } module "my-cloud-run-app" { source = "DataDog/cloud-run-datadog/google" version = "~> 1.0" project = "my-gcp-project" name = "my-cloud-run-app" location = "us-central1" datadog_api_key = var.datadog_api_key datadog_service = "test-service" // your application service datadog_version = "0.0.0" // your code version datadog_env = "prod" // your application environment datadog_enable_logging = true deletion_protection = false build_config = { function_target = "helloHttp" // your function entry point image_uri = "us-docker.pkg.dev/cloudrun/container/hello" base_image = "us-central1-docker.pkg.dev/serverless-runtimes/google-22-full/runtimes/your-runtime" // base image for your runtime enable_automatic_updates = true } template = { containers = [ { name = "main" image = "us-docker.pkg.dev/cloudrun/container/hello" base_image_uri = "us-central1-docker.pkg.dev/serverless-runtimes/google-22-full/runtimes/your-runtime" // base image for your runtime resources = { limits = { cpu = "1" memory = "512Mi" } } ports = { container_port = 8080 } env = [ { name = "DD_TRACE_ENABLED", value = "true" }, ] }, ] } } ``` See the Environment Variables for more information on the configuration options available through the `env`. Ensure the container port for the main container is the same as the one exposed in your Dockerfile/service. If you haven't already, initialize your Terraform project: ```shell terraform init ``` To deploy your app, run: ```shell terraform apply ``` {% /tab %} {% tab title="Other" %} After deploying your Cloud Run app, you can manually modify your app's settings to enable Datadog monitoring. 1. Create a **Volume** with `In-Memory` volume type. 1. Add a **new container** with image URL: `gcr.io/datadoghq/serverless-init:`. See the [latest releases on Docker Hub](https://hub.docker.com/r/datadog/serverless-init) to pin a specific version. 1. Add the volume mount to every container in your application. Choose a path such as `/shared-volume`, and remember it for the next step. 1. Add the following environment variables to your `serverless-init` sidecar container: - `DD_SERVICE`: A name for your service. For example, `gcr-sidecar-test`. - `DD_ENV`: A name for your environment. For example, `dev`. - `DD_SERVERLESS_LOG_PATH`: Your log path. For example, `/shared-volume/logs/*.log`. The path must begin with the mount path you defined in the previous step. - `DD_API_KEY`: Your [Datadog API key](https://app.datadoghq.com/organization-settings/api-keys). - `FUNCTION_TARGET`: The entry point of your function. For example, `Main`. For a list of all environment variables, including additional tags, see Environment variables. {% /tab %} 1. **Set up logs**. In the previous step, you created a shared volume. You may have also set the `DD_SERVERLESS_LOG_PATH` environment variable, which defaults to `/shared-volume/logs/app.log`. In this step, configure your logging library to write logs to the file set in `DD_SERVERLESS_LOG_PATH`. You can also set a custom format for log/trace correlation and other features. Datadog recommends setting the environment variable `DD_SOURCE=ruby` in your sidecar container to enable advanced Datadog log parsing. Then, update your logging library. For example, you can use Ruby's native `logger` library: ```ruby LOG_FILE = "/shared-logs/logs/app.log" FileUtils.mkdir_p(File.dirname(LOG_FILE)) logger = Logger.new(LOG_FILE) logger.formatter = proc do |severity, datetime, progname, msg| "[#{datetime}] #{severity}: [#{Datadog::Tracing.log_correlation}] #{msg}\n" end logger.info "Hello World!" ``` For more information, see [Correlating Ruby Logs and Traces](https://docs.datadoghq.com/tracing/other_telemetry/connect_logs_and_traces/ruby/). 1. **Add a service label in Google Cloud**. In your Cloud Run service's info panel, add a label with the following key and value: | Key | Value | | --------- | ---------------------------------------------------------------------------------------------- | | `service` | The name of your service. Matches the value provided as the `DD_SERVICE` environment variable. | See [Configure labels for services](https://cloud.google.com/run/docs/configuring/services/labels) in the Cloud Run documentation for instructions. **Send custom metrics**. To send custom metrics, [install the DogStatsD client](https://docs.datadoghq.com/extend/dogstatsd/?tab=ruby#install-the-dogstatsd-client) and [view code examples](https://docs.datadoghq.com/metrics/custom_metrics/dogstatsd_metrics_submission/?tab=ruby#code-examples-5). In Serverless Monitoring, only the *distribution* metric type is supported. ### Environment variables{% #environment-variables %} | Variable | Description | Container | | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------- | | `DD_API_KEY` | [Datadog API key](https://app.datadoghq.com/organization-settings/api-keys) - **Required** | Sidecar container | | `DD_SITE` | [Datadog site](https://docs.datadoghq.com/getting_started/site/) - **Required** | Sidecar container | | `DD_SERVICE` | Datadog Service name. **Required** | Both containers | | `DD_SERVERLESS_LOG_PATH` | The path where the sidecar should tail logs from. Recommended to set to `/shared-volume/logs/app.log`. | Sidecar container | | `DD_LOGS_INJECTION` | When true, enrich all logs with trace data for supported loggers. See [Correlate Logs and Traces](https://docs.datadoghq.com/tracing/other_telemetry/connect_logs_and_traces/) for more information. | Application container | | `DD_VERSION` | See [Unified Service Tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging/). | Both containers | | `DD_ENV` | See [Unified Service Tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging/). | Both containers | | `DD_SOURCE` | Set the log source to enable a [Log Pipeline](https://docs.datadoghq.com/logs/log_configuration/pipelines) for advanced parsing. To automatically apply language-specific parsing rules, set to `ruby`, or use your custom pipeline. Defaults to `cloudrun`. | Sidecar container | | `DD_TAGS` | Add custom tags to your logs, metrics, and traces. Tags should be comma separated in key/value format (for example: `key1:value1,key2:value2`). | Sidecar container | | `FUNCTION_TARGET` | Required for correct tagging. The entry point of your function. For example, `Main`. You can also find `FUNCTION_TARGET` on the source tab inside Google console: `Function entry point`. | Sidecar container | **Do not set** the following environment variables in your serverless environment. They should only be set in non-serverless environments. - `DD_AGENT_HOST` - `DD_TRACE_AGENT_URL` ## Troubleshooting{% #troubleshooting %} This integration depends on your runtime having a full SSL implementation. If you are using a slim image, you may need to add the following command to your Dockerfile to include certificates: ```dockerfile RUN apt-get update && apt-get install -y ca-certificates ``` To have your Cloud Run services appear in the [software catalog](https://cloud.google.com/run/docs/configuring/services/labels), you must set the `DD_SERVICE`, `DD_VERSION`, and `DD_ENV` environment variables. ## Further reading{% #further-reading %} - [Tracing Ruby Applications](https://docs.datadoghq.com/tracing/trace_collection/automatic_instrumentation/dd_libraries/ruby/) - [Correlating Ruby Logs and Traces](https://docs.datadoghq.com/tracing/other_telemetry/connect_logs_and_traces/ruby/)