Struct OtelTracingLayer

pub struct OtelTracingLayer<T: SpanAttributesExtractor> { /* private fields */ }

Tower middleware to create an OpenTelemetry tracing span for Lambda invocations.

This layer wraps a Lambda service to automatically create and configure OpenTelemetry spans for each invocation. It supports:

• Automatic span creation with configurable names
• Automatic attribute extraction from supported event types
• Context propagation from HTTP headers
• Response status tracking

Example

use lambda_otel_lite::{init_telemetry, OtelTracingLayer, TelemetryConfig, SpanAttributes};
use lambda_runtime::{service_fn, Error, LambdaEvent, Runtime};
use aws_lambda_events::event::apigw::ApiGatewayV2httpRequest;
use tower::ServiceBuilder;

async fn handler(event: LambdaEvent<ApiGatewayV2httpRequest>) -> Result<serde_json::Value, Error> {
    Ok(serde_json::json!({ "statusCode": 200 }))
}

let (_, completion_handler) = init_telemetry(TelemetryConfig::default()).await?;

// Create a layer with custom name
let layer = OtelTracingLayer::new(completion_handler)
    .with_name("api-handler");

// Apply the layer to your handler
let service = ServiceBuilder::new()
    .layer(layer)
    .service_fn(handler);

Runtime::new(service).run().await

Implementations

impl<T: SpanAttributesExtractor> OtelTracingLayer<T>

pub fn new(completion_handler: TelemetryCompletionHandler) -> Self

Create a new OpenTelemetry tracing layer with the required completion handler.

The completion handler is used to signal when spans should be exported. It’s typically obtained from init_telemetry.

Arguments

• completion_handler - Handler for managing span export timing

pub fn with_name(self, name: impl Into<String>) -> Self

Set the span name.

This name will be used for all spans created by this layer. It should describe the purpose of the Lambda function (e.g., “process-order”, “api-handler”).

Arguments

• name - The name to use for spans

Trait Implementations

impl<T: Clone + SpanAttributesExtractor> Clone for OtelTracingLayer<T>

fn clone(&self) -> OtelTracingLayer<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S, T> Layer<S> for OtelTracingLayer<T>

where T: SpanAttributesExtractor + Clone,

type Service = OtelTracingService<S, T>

The wrapped service

fn layer(&self, inner: S) -> Self::Service

Wrap the given service with the middleware, returning a new service that has been decorated with the middleware.