update opencensus packages

[mightyguava]

The prometheus and datadog exporters were moved into contrib.go.opencensus.io (this whole repo seems unstable and experimental btw).

I'm updating these because I'm vendoring ld-relay into another repo, to use as a library

[eli-darkly]

This is currently only passing CI in Go 1.10.

[mightyguava]

Depending on opencensus probably wasn't the wisest choice:

[mightyguava]

I pinned the version fo go.opencensus.io, hopefully that fixes things? 🙏

[mightyguava]

@eli-darkly we are green!

[eli-darkly]

@mightyguava Well, since the ld-relay build uses dep, pinning the version does work. That won't help anyone who pulls this code into an app without using dep. But it's probably reasonable to require that they use it if they do that.

[mightyguava]

I think it's reasonable to expect people pulling it ld-relay as a library (I might be the only one), to use either dep or go mod.

[alecthomas]

Any chance we can get this merged?

[mightyguava]

I'm one of the people who don't use dep and ran into build breakages. This fixes things for people who use dep. I don't really understand why there's hesitance to merging this pr.

@alecthomas We are using my fork at https://github.com/mightyguava/ld-relay internally. Feel free to make PRs there for whatever you want to change.

[eli-darkly]

@mightyguava There wasn't any deliberate "hesitance"; we just had a lot of other things going on with ld-relay, and had not had a chance to look at this again since the build got fixed. We will take another look. Sorry for the delay.

[eli-darkly]

[tracked internally as 55052]

[eli-darkly]

This looks correct; I'll merge it now into onto a branch where we can do some follow-up testing, and assuming there are no unforeseen problems we'll release it ASAP.

[eli-darkly]

And sorry again for the extended delay.

[eli-darkly]

@mightyguava Problem: the Prometheus integration appears to be broken now, due to a transitive dependency on a buggy version of github.com/prometheus/client_golang. To fix this, we'll need to either make dep override the transitive dependency, or wait until we can get that package patched.

Unfortunately, we released 5.8.2 with these changes before we noticed the problem. So we do need to put out another patch ASAP, and I'm not sure if the best way to go at this point is to use an override as I mentioned, or just roll back the dependency change for now. But I'm unclear on what kind of build-breakage you were seeing before, that made this necessary; I should have asked that in the first place.

[mightyguava]

Hey, sorry for the breakage. Feel free to roll this back since we do keep our own fork.

The reason we needed to bump this is because when this repo is used with go modules, it automatically pulls in a newer version of opencensus that has breaking API changes, and we wanted to keep the code in sync. The fork basically just maintains the go module manifests. We had to lock the version in this upstream repo though, because without it, upgrading pulled in a version of opencensus that was really broken.