Skip to content

Latest commit

 

History

History
141 lines (110 loc) · 5.57 KB

README.md

File metadata and controls

141 lines (110 loc) · 5.57 KB
Raw

AWS OTel .NET SDK for Lambda

NuGet version badge NuGet download count badge

This repo contains SDK to instrument Lambda handler to create incoming span.

Installation

dotnet add package OpenTelemetry.Instrumentation.AWSLambda

Configuration

Add AddAWSLambdaConfigurations() to TracerProvider.

TracerProvider tracerProvider = Sdk.CreateTracerProviderBuilder()
        // add other instrumentations
        .AddAWSLambdaConfigurations(options => options.DisableAwsXRayContextExtraction = true)
        .Build();

AWSLambdaInstrumentationOptions

AWSLambdaInstrumentationOptions contains various properties to configure AWS lambda instrumentation:

Instrumentation

AWSLambdaWrapper contains tracing methods covering different types of function handler method signatures. AWSLambdaWrapper.Trace() and AWSLambdaWrapper.TraceAsync() are used for wrapping synchronous and asynchronous function handlers respectively. The ActivityContext parentContext parameter is optional and used to pass a custom parent context. If the parent is not passed explicitly then it's either extracted from the input parameter or uses AWS X-Ray headers if AWS X-Ray context extraction is enabled (see configuration property DisableAwsXRayContextExtraction).

Note

If tracing is required when AWS X-Ray is disabled, the DisableAwsXRayContextExtraction property needs to be set to true. This will instruct the instrumentation to ignore the "not sampled" trace header automatically sent when AWS X-Ray is disabled.

The sequence of the parent extraction: explicit parent -> parent from input parameter -> AWS X-Ray headers -> default The parent extraction is supported for the input types listed in the table below:

Type Parent extraction source
APIGatewayProxyRequest, APIGatewayHttpApiV2ProxyRequest HTTP headers of the request
SQSEvent Attributes of the last SQSMessage (if SetParentFromMessageBatch is true)
SNSEvent Attributes of the last SNSRecord

Lambda Function

  1. Create a wrapper function with the same signature as the original Lambda function but an added ILambdaContext parameter if it was not already present. Call AWSLambdaWrapper.Trace() or AWSLambdaWrapper.TraceAsync() API and pass TracerProvider, original Lambda function and its parameters.

  2. Set the wrapper function as the Lambda handler input.

// new Lambda function handler passed in
public string TracingFunctionHandler(JObject input, ILambdaContext context)
=> AWSLambdaWrapper.Trace(tracerProvider, OriginalFunctionHandler, input, context);

public string OriginalFunctionHandler(JObject input, ILambdaContext context)
{
    var S3Client = new AmazonS3Client();
    var httpClient = new HttpClient();
    _ = S3Client.ListBucketsAsync().Result;
    _ = httpClient.GetAsync("https://aws.amazon.com").Result;
    return input?.ToString();
}

Lambda Function - Asp.Net Core

For using base classes from package Amazon.Lambda.AspNetCoreServer, override the FunctionHandlerAsync function in LambdaEntryPoint.cs file. Call AWSLambdaWrapper.TraceAsync() API and pass TracerProvider, original Lambda function and its inputs as parameters. Below is an example if using APIGatewayProxyFunction as base class.

public override async Task<APIGatewayProxyResponse> FunctionHandlerAsync(
    APIGatewayProxyRequest request, ILambdaContext lambdaContext)
=> await AWSLambdaWrapper.TraceAsync(tracerProvider, base.FunctionHandlerAsync,
    request, lambdaContext);

Example

A more detailed Lambda function example that takes a JObject and ILambdaContext as inputs.

public class Function
{
    public static TracerProvider tracerProvider;

    static Function()
    {
        tracerProvider = Sdk.CreateTracerProviderBuilder()
                .AddHttpClientInstrumentation()
                .AddAWSInstrumentation()
                .AddOtlpExporter()
                .AddAWSLambdaConfigurations(options => options.DisableAwsXRayContextExtraction = true)
                .Build();
    }

    public string TracingFunctionHandler(JObject input, ILambdaContext context)
    => AWSLambdaWrapper.Trace(tracerProvider, FunctionHandler, input, context);

    /// <summary>
    /// A simple function that takes a JObject input and sends downstream http
    /// request to aws.amazon.com and aws request to S3.
    /// </summary>
    public string FunctionHandler(JObject input, ILambdaContext context)
    {
        var S3Client = new AmazonS3Client();
        var httpClient = new HttpClient();
        _ = S3Client.ListBucketsAsync().Result;
        _ = httpClient.GetAsync("https://aws.amazon.com").Result;
        return input?.ToString();
    }
}

Reference