AWS Lambda Node.js — Zero-Code Instrumentation with Elven Observability Layer

Overview

Elven provides instrumentation Layers for AWS Lambda, enabling:

• Automatic collection of logs, metrics, and traces.

• Data forwarding to the Elven Observability platform with zero code.

• Fully managed via Layers and environment variables.

• Compatible with any Lambda runtime language through our universal bootstrap.

This documentation describes how to instrument your Lambda using the official Elven Layers.

Prerequisites

• The Lambda function must already be implemented and functional.

• Permission to modify the Lambda configuration (Layers and environment variables).

• Have the Tenant ID and authentication Token provided by Elven Observability.

If you do not have the Tenant ID and Token, access:

https://elvenobservability.com

Or request it from the Elven support team.

Configuring the Lambda

Step 1 — Add the Elven Layer

Choose the Layer according to your case:

Layer	ARN
elven-instrumentation-js (complete: logs + metrics + traces)	(use the list of ARNs below)

Example (us-east-1):

arn:aws:lambda:us-east-1:204595508824:layer:elven-instrumentation-js:1

• In the AWS Lambda console, go to your function > Configuration > Layers > Add a layer.

• Add the Layer using the ARN for your region.

Step 2 — Modify the Handler

Very important: By default, the Elven Layer intercepts the Lambda execution through its own bootstrap.

You must:

Set the actual path of your handler in the AWS_LAMBDA_FUNCTION_HANDLER environment variable.

Example:

AWS_LAMBDA_FUNCTION_HANDLER=src/index.handler

Set the Elven bootstrap:

In the console, add:

AWS_LAMBDA_EXEC_WRAPPER=/opt/bootstrap

This ensures that the Elven bootstrap initializes first, before calling your actual handler.

Step 3 — Configure the environment variables

Below is the complete list:

Variable	Description	Example
AWS_LAMBDA_FUNCTION_HANDLER	Actual path of your handler	src/index.handler
AWS_LAMBDA_EXEC_WRAPPER	Always /opt/bootstrap	/opt/bootstrap
LOKI_URL	Elven Loki endpoint	https://loki.elvenobservability.com/loki/api/v1/push
LOKI_AUTH_TOKEN	Authentication token	(fornecido pela Elven)
LOKI_TENANT_ID	Client Tenant ID	(fornecido pela Elven)
LOKI_APP_NAME	Application name (for labeling)	my-app
LOKI_COOPERATIVE_MODE	Enable resilient mode	true
LOKI_PURE_HANDLER	Safe interception mode	true
LOKI_SAFE_INIT	Enable protected startup	true
OTEL_EXPORTER_OTLP_ENDPOINT	Endpoint of your OTEL Collector	http://my-otel-collector.com:4318
OTEL_SERVICE_NAME	Service name (traces)	my-app
OTEL_RESOURCE_ATTRIBUTES	Additional resource attributes	service.name=my-app,environment=production
OTEL_LAMBDA_TRACE_MODE	Enable trace capture	capture
OTEL_LOG_LEVEL	Internal SDK log	error
OTEL_PROPAGATORS	Active propagators	tracecontext,baggage,xray
OTEL_TRACES_SAMPLER	Trace sampling	always_on

Important Note:

• The LOKI_AUTH_TOKEN e LOKI_TENANT_ID variables are provided by Elven.

• An active and accessible OpenTelemetry Collector is also required for sending traces and metrics (OTEL_EXPORTER_OTLP_ENDPOINT).

• If you do not have the Token, Tenant ID, or Collector configured, please contact Elven Support.

Step 4 — Deploy

Now just save and deploy your Lambda.

Instrumentation will be automatic.

Practical examples

Fully functional example

Imagine your original Lambda configured with the handler:

Handler: src/index.handler

After instrumentation with Elven:

• In the Lambda Handler field (AWS Console), you can enter anything — it doesn't matter.

• Add:

AWS_LAMBDA_FUNCTION_HANDLER=src/index.handler
AWS_LAMBDA_EXEC_WRAPPER=/opt/bootstrap
# e todas as variáveis do bloco 3

Done. No code changes are required.

Common Issues & Troubleshooting

Problem	Cause	Solution
Cannot find handler.	AWS_LAMBDA_FUNCTION_HANDLER is not set correctly.	Check the exact handler path, including subfolders.
Initialization timeout.	Network failure when connecting to Loki/OTEL.	Check if your Lambda has access to the internet or private endpoints.
Data is not showing up in Elven.	Incorrect Token or Tenant.	Request new authentication data from support.

Support & Contact

If you need help with configuration, onboarding, or troubleshooting, please contact us:

📧 [email protected]

🌐 https://elvenobservability.com

Full Layer ARNs (by region)

• us-east-1: arn:aws:lambda:us-east-1:204595508824:layer:elven-instrumentation-js:1

• us-east-2: arn:aws:lambda:us-east-2:204595508824:layer:elven-instrumentation-js:1

• us-west-1: arn:aws:lambda:us-west-1:204595508824:layer:elven-instrumentation-js:1

• us-west-2: arn:aws:lambda:us-west-2:204595508824:layer:elven-instrumentation-js:1

• sa-east-1: arn:aws:lambda:sa-east-1:204595508824:layer:elven-instrumentation-js:1