Setting up tracing for Ruby Lambda functions

Enabling tracing by using AWS web console

To enable tracing of Ruby Lambda functions through the AWS web console, complete the following steps:

1. Add the Instana Lambda layer to your function:

   1. On the configuration page of your Lambda function, click Layers.

      

   2. In the Layers box, click Add a layer.

      

   3. On the Add layer page, select the Specify an ARN option as the layer source.

   4. In the Specify an ARN field, copy and paste the ARN for the Instana Lambda Layer that matches your region. You can find the right ARN for the Instana Lambda Layer in the Instana Lambda Layers section.

   5. Click Add.

      

2. Instrument the handler function:

   Wrap your Ruby lambda function in a Instana.serverless.wrap_aws block, passing the event and context as arguments as shown in the following example. This wrapper automatically creates spans for your Lambda invocation and handles the tracing context.

   require 'bundler/setup'
   
   require 'json'
   require 'instana'
   
   def lambda_handler(event:, context:)
     Instana.serverless.wrap_aws(event, context) do
       # Your original Lambda function code goes here
       {
         statusCode: 200,
         body: {
           message: "Hello World!",
         }.to_json
       }
     end
   end
   

   With the wrapper approach, you can maintain your existing handler function name while adding Instana tracing capabilities. You don't need to change your Lambda handler configuration in the AWS console.

3. Set environment variables:

   Add the following environment variables:

   • INSTANA_ENDPOINT_URL: Your serverless monitoring endpoint. Make sure to use the correct value for your region that starts with https://serverless-.
   • INSTANA_AGENT_KEY: Your agent key.
   • LAMBDA_HANDLER: Your custom handler, if you are not using the default handler lambda_function.lambda_handler.

   You can also obtain the correct values for these environment variables from your Instana UI. To obtain the correct values for these environment variables, click Data sources > Install agents > AWS Lambda.

Enabling tracing by using AWS CLI

The following example shows an AWS CLI command that might serve as a starting point if you want to automate the Instana integration of your AWS Lambda functions:

# Do not copy and paste this verbatim!
# It will overwrite any previously defined collection of layers and
# environment variables.
aws --region $YOUR_REGION lambda update-function-configuration \
  --function-name $YOUR_LAMBDA_FUNCTION_NAME \
  --layers $INSTANA_LAYER_ARN \
  --environment ""Variables={INSTANA_ENDPOINT_URL=... , INSTANA_AGENT_KEY=... , LAMBDA_HANDLER=...}""

Unlike some other language integrations, you don't need to modify the handler configuration when you use the Ruby integration. The Ruby integration uses a wrapper approach that preserves your original handler function.