--- title: Instrumenting a Ruby Container App In-Container description: Datadog, the leading service for cloud-scale monitoring. breadcrumbs: >- Docs > Serverless > Azure Container Apps > In-Container Instrumentation > Instrumenting a Ruby Container App In-Container --- # Instrumenting a Ruby Container App In-Container ## 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**. Datadog publishes new releases of the `serverless-init` container image to Google's gcr.io, AWS's ECR, and on Docker Hub: | hub.docker.com | gcr.io | public.ecr.aws | | ----------------------- | -------------------------------- | -------------------------------------- | | datadog/serverless-init | gcr.io/datadoghq/serverless-init | public.ecr.aws/datadog/serverless-init | Images are tagged based on semantic versioning, with each new version receiving three relevant tags: - `1`, `1-alpine`: use these to track the latest minor releases, without breaking changes - `1.x.x`, `1.x.x-alpine`: use these to pin to a precise version of the library - `latest`, `latest-alpine`: use these to follow the latest version release, which may include breaking changes Add the following instructions and arguments to your Dockerfile. ```dockerfile COPY --from=datadog/serverless-init: /datadog-init /app/datadog-init ENTRYPOINT ["/app/datadog-init"] CMD ["rails", "server", "-b", "0.0.0.0"] ``` {% collapsible-section %} Alternative configuration: Datadog expects `serverless-init` to be the top-level application, with the rest of your app's command line passed in for `serverless-init` to execute. If you already have an entrypoint defined inside your Dockerfile, you can instead modify the CMD argument. ```dockerfile CMD ["/app/datadog-init", "rails", "server", "-b", "0.0.0.0"] ``` If you require your entrypoint to be instrumented as well, you can instead swap your entrypoint and CMD arguments. ```dockerfile ENTRYPOINT ["/app/datadog-init"] CMD ["/your_entrypoint.sh", "rails", "server", "-b", "0.0.0.0"] ``` As long as your command to run is passed as an argument to `datadog-init`, you will receive full instrumentation. {% /collapsible-section %} 1. **Set up logs**. To enable logging, set the environment variable `DD_LOGS_ENABLED=true`. This allows `serverless-init` to read logs from stdout and stderr. Datadog also recommends setting the environment variable `DD_SOURCE=ruby` to enable advanced Datadog log parsing. To enable log-trace correlation, you need to include `Datadog::Tracing.log_correlation` in your log format. For example: ```ruby logger = Logger.new(STDOUT) 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. **Configure your application**. After the container is built and pushed to your registry, set the required environment variables for the Datadog Agent: - `DD_API_KEY`: Your [Datadog API key](https://app.datadoghq.com/organization-settings/api-keys), used to send data to your Datadog account. For privacy and safety, configure this API key as a Google Cloud Secret. - `DD_SITE`: Your [Datadog site](https://docs.datadoghq.com/getting_started/site/). For example, `datadoghq.com`. For more environment variables, see the Environment variables section on this page. **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, only the *distribution* metric type is supported. ### Environment variables{% #environment-variables %} | Variable | Description | | -------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `DD_API_KEY` | [Datadog API key](https://app.datadoghq.com/organization-settings/api-keys) - **Required** | | `DD_SITE` | [Datadog site](https://docs.datadoghq.com/getting_started/site/) - **Required** | | `DD_SERVICE` | Datadog Service name. **Required** | | `DD_AZURE_SUBSCRIPTION_ID` | Azure Subscription ID. **Required** | | `DD_AZURE_RESOURCE_GROUP` | Azure Resource Group name. **Required** | | `DD_LOGS_ENABLED` | When true, send logs (stdout and stderr) to Datadog. Defaults to false. | | `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. | | `DD_VERSION` | See [Unified Service Tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging/). | | `DD_ENV` | See [Unified Service Tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging/). | | `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 `containerapp`. | | `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`). | **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 Azure Container Apps appear in the [software catalog](https://docs.datadoghq.com/internal_developer_portal/software_catalog/), 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/)