Automatically remove consecutive slashes in HTTP span names.

[h0cheung]

Is your feature request related to a problem? Please describe.

In certain project implementations, when users generate HTTP routes based on string concatenation, those defining these strings may prefix and suffix each string with a forward slash (/) to prevent routing issues caused by colleagues forgetting to add the slash.

As a result, two consecutive forward slashes may appear in the route definition after concatenation. While this does not affect program execution, it ultimately appears in the Span name.

Describe the solution you'd like

We can automatically remove consecutive slashes from the route when creating the Span.

Describe alternatives you've considered

No response

Additional context

No response

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[laurit]

Please be more specific, which framework instrumentation has this issue. If possible provide a minimal sample app that illustrates the issue.

[h0cheung]

Please be more specific, which framework instrumentation has this issue. If possible provide a minimal sample app that illustrates the issue.

Currently, otel does not appear to perform any additional processing for any frameworks. We commonly use Spring; to reproduce the issue, you can write a program in Spring as follows:

public class Constants {
    public static final String API_PREFIX = "/some/prefix/";
}

@RestController
public class AppController {
    @GetMapping(Constants.API_PREFIX + "/test")
    public String test() {
        return "ok";
    }
}

The concatenated routing string is /some/prefix//test. In Spring, multiple consecutive // characters are meaningless, so it is equivalent to /some/prefix/test. This FR aims to support using the latter as the Span name. Currently, SkyWalking-Java supports this by default.

[laurit]

In Spring, multiple consecutive // characters are meaningless, so it is equivalent to /some/prefix/test

As far as I can tell this is true for older spring versions but in 6.0 or perhaps 5.3 using a // results in 404. Could be related to https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-servlet/handlermapping-path.html and whether it uses AntPathMatcher or not.

[breedx-splk]

You're literally putting a double slash // in the route definition -- I'm not convinced that the instrumentation should change that. You could "fix" this by removing the trailing slash in the prefix, right?

[jaydeluca]

caused by colleagues forgetting to add the slash.

in my opinion, it is the responsibility of the observability tool to expose this user-made mistake (by including it in the span name), as opposed to masking it.