[app-configuration] Adding distributed tracing

[richardpark-msft]

Some changes, mostly just refactoring.

One thing I discovered as I was doing this was that (not sure why) the listConfigurationSettingsOptions and listRevisionsOptions weren't exposing inherited properties from RequestOptionsBase (and thus I couldn't add the spanOptions).

I fixed this by just flattening them out into their own classes which appears to have solved it and was going to happen anyways since I need to do something similar to improve doc generation.

[chradek]

One thing you'll need to be able to do is add the TracingPolicy from core-http as part of your request pipeline. You can see how keyvaults does that here:

azure-sdk-for-js/sdk/keyvault/keyvault-secrets/src/index.ts

Line 115 in eed5c32

requestPolicyFactories = requestPolicyFactories.concat([

The reason you want this is that this policy will create a span specific to the HTTP request (we'll add more properties to it in the future) and forwards the span context by adding the traceparent/tracestate headers to the outgoing request.

[xirzec]

Generally looks good! 👍

Left a couple comments.

I had debated about making a helper like this (where the traced code happens inside a callback.)

I think why I shied away from it is I remember having to debug similar code in F12 where it was really annoying if you stepped into the tracing code since you had to step through goop just to get back to your function body. So you ended up having to set a breakpoint in the inner function body and continue, whereas if you do the start/end pattern the developer can simply stepOver the two helper calls.

Something to think about 😄

[richardpark-msft]

Generally looks good! 👍

Left a couple comments.

I had debated about making a helper like this (where the traced code happens inside a callback.)

I think why I shied away from it is I remember having to debug similar code in F12 where it was really annoying if you stepped into the tracing code since you had to step through goop just to get back to your function body. So you ended up having to set a breakpoint in the inner function body and continue, whereas if you do the start/end pattern the developer can simply stepOver the two helper calls.

Something to think about 😄

I'm with you on the steppability-issue with it. I'm more worried about consistently applying the pattern. Perhaps this is something we can do some work on with the code generator at some point so these classes will be a bit cleaner.

[richardpark-msft]

One thing you'll need to be able to do is add the TracingPolicy from core-http as part of your request pipeline. You can see how keyvaults does that here:

azure-sdk-for-js/sdk/keyvault/keyvault-secrets/src/index.ts

Line 115 in eed5c32

requestPolicyFactories = requestPolicyFactories.concat([

The reason you want this is that this policy will create a span specific to the HTTP request (we'll add more properties to it in the future) and forwards the span context by adding the traceparent/tracestate headers to the outgoing request.

Added. Check out appConfigurationClient.ts's constructor.

[xirzec]

Looks good!