Reduce size of dependency

[seanamos]

Given the intended target for this package is lambda functions, minimizing the impact on the size of the final binary and reducing dependencies should be a high priority.

Adding datadog-lambda-go as a dependency can significantly increase the size of the final binary and brings in a large amount of transitive dependencies.

Before adding dependency:

➜ du -h bin/linux/arm64/*
8.7M    bin/linux/arm64/xxx

After adding dependency:

➜ du -h bin/linux/arm64/*
 32M    bin/linux/arm64/xxx

Specifications

• Datadog Go Lambda package version: 1.47.0
• Go version: 1.23.5

[krzysiek1507]

Hey! Updating this package to use github.com/aws/aws-xray-sdk-go v2 should reduce the size I guess? v2 got rid of AWS SDK Go v1.

[krzysiek1507]

cc @nhulston

[krzysiek1507]

I opened a PR with the update #190

[seanamos]

After upgrading to v1.22.0, we saw a reduction of 4mb. So 8.7M without the dependency, 28M with it, down from 32M.

Trending in the right direction.

[debugmiller]

I believe the issue here is that this library disables go's dead code elimination which can significantly increase binary sizes. This is because one of this library's transitive dependencies uses reflect.Value.MethodByName which disables dead code elimination (see this blog).

The import chain is:

• the init() function in golang.org/x/net/trace uses html/template which disables dead code elimination because it calls reflect.Value.MethodByName
• golang.org/x/net/trace is imported by google.golang.org/grpc
• google.golang.org/grpc is imported by github.com/aws/aws-xray-sdk-go/v2/xray
• github.com/aws/aws-xray-sdk-go/v2/xray is imported by github.com/DataDog/datadog-lambda-go/internal/trace

In short the problem is with the import here. It looks like only a small number of functionality is needed. Consider reimplementing those functions.

Alternatively, users can opt out of grpc tracing (if their usecase allows) by building with go build -tags grpcnotrace per this comment