# Sinatra

> Send traces to Last9 from a Sinatra app using OpenTelemetry

Source: https://last9.io/docs/integrations/frameworks/ruby/sinatra/

Sinatra is a lightweight web application framework written in Ruby. This comprehensive guide will help you instrument your Sinatra application with OpenTelemetry and smoothly send the traces to a Last9 cluster. You can also check out the example application on [GitHub↗](https://github.com/last9/opentelemetry-examples/tree/master/ruby/sinatra).

## Pre-requisites

1. You've a Sinatra application.
2. You have signed up for [Last9](https://app.last9.io), created a cluster, and obtained the following OTLP credentials from the [Integrations](https://app.last9.io/integrations?integration=OpenTelemetry) page:
   - `endpoint`
   - `auth_header`

## Install OpenTelemetry packages

To install the required packages, add the following lines to your Gemfile:

```ruby
# Gemfile
source 'https://rubygems.org'

gem 'sinatra'

gem 'dotenv'
gem 'opentelemetry-sdk'
gem 'opentelemetry-exporter-otlp'
gem 'opentelemetry-instrumentation-all'
```

Then, run the following command to install the packages:

```bash
bundle install
```

## Set the environment variables

Create a `.env` file in the root directory of your application and add the following environment variables:

```bash
OTEL_SERVICE_NAME=sinatra-api-service
OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.last9.io
OTEL_EXPORTER_OTLP_HEADERS="Authorization=<BASIC_AUTH_HEADER>"
OTEL_TRACES_EXPORTER=otlp
```

> Note: Replace `<BASIC_AUTH_HEADER>` with the URL encoded value of the basic auth header obtained from the [Integrations](https://app.last9.io/integrations?integration=OpenTelemetry) page.

In `app.rb`, add the following code to load the environment variables:

```ruby
# app.rb
require 'dotenv/load'
# Rest of the code...
```

:::note
You can also other mechanisms to load environment variables and configuration such as loading a YAML file.
:::

## Instrument your application

Create a new file `instrumentation.rb` and add the following code:

```ruby
require 'opentelemetry/sdk'
require 'opentelemetry/exporter/otlp'
require 'opentelemetry/instrumentation/all'

OpenTelemetry::SDK.configure do |c|
  c.service_name = 'sinatra-api-service'
  c.use_all() # enables all instrumentation!
end
```

This code snippet configures the OpenTelemetry SDK to use the OTLP exporter and enables all instrumentation.
We will require this file in `app.rb` to instrument the application.

In `app.rb`, require the `instrumentation.rb` file:

```ruby
# app.rb

require_relative 'instrumentation'

# Rest of the code...
```

## Run the application

Run the Sinatra application using the following command:

```bash
ruby app.rb
```

## Visualize the traces

After running the Sinatra app, you can visualize the traces in the Last9's APM dashboard.

![image](../../../../../../assets/content/docs/integrations/frameworks/ruby/sinatra/sinatra.png)

---

## Running on Kubernetes

If you deploy your Sinatra app to Kubernetes, enrich traces with `k8s.*` semantic convention attributes (pod, namespace, node, deployment) using the Kubernetes Downward API. See [Kubernetes Resource Attributes](/docs/integrations/frameworks/ruby/kubernetes-resource-attributes/) for the deployment manifest.

## Troubleshooting

Please get in touch with us on [Discord](https://discord.com/invite/Q3p2EEucx9) or [Email](mailto:support@last9.io) if you have any questions.