How to ignore or rename spans in library code?

[hverlin]

I have a service with the following code, which relies on gitlab.com/gitlab-org/api/client-go

func FetchFileFromGitLab(logger logging.Logger, gitlabClient *gitlab.Client, projectId any, location string, ref string) ([]byte, error) {
	file, _, err := gitlabClient.RepositoryFiles.GetFile(projectId, location, &gitlab.GetFileOptions{Ref: &ref})

       // ...
}

The GetFile function in the GitLab go client wraps the http client which is being instrumented:
https://gitlab.com/gitlab-org/api/client-go/-/blob/0034e1e813b95c313302c9fe0ac703a904e9f6bd/repository_files.go#L95

The issue is that each request to GitLab shows up as a different resource in Datadog instead of being normalized like
GET /v4/api/projects/:id/repository/files/:file.

It makes sense that the instrumentation cannot detect which path segments are parameters or not. However, the default behavior is causing an issue: it creates one resource name per URL called, making the endpoints list not very useful.

Is there a way to either:

• prevent this code from being instrumented (using //orchestrion:ignore does not seem to work)
• or rename the spans (without using DD_APM_REPLACE_TAGS in the agent)?

Thank you!

[genesor]

Hi @hverlin, thanks for trying out orchestrion.

Right now using automatic instrumentation it is not possible to change this behavior. The current orchestrion instrumentation around an net/http client (which is used under the hood by the GitLab client) uses a ResourceNamer that relies on the path (v2) (also for the v1 in a different way) as resource name. This is something that the team discussed this week because this behavior is not ideal for users.

A URL quantizer has been recently introduced in dd-trace-go#3471 that could be leveraged in a future v2.x release to help address this issue.

In the meantime, if you'd like to rename the resources of the span you'd need to manually instrument your code by wrapping the client used by the GitLab client.

To do so you'd need to follow those steps:

1. Remove the net/http contrib from the auto instrumentation configuration:
   • Copy the orchestrion.tool.go imports here in your own orchestrion.tool.go
   • Remove the mention to gopkg.in/DataDog/dd-trace-go.v1/contrib/net/http in the import list
   • Note that you'd also need to manually instrument the server part because both client and server are instrumented with the same package.
2. Manually instrument the http clients and servers using dd-trace-go contrib public API (example here) and use a ResourceNamer here that would have the URL Quantizer logic you want.

Let me know if this solution works for you.