Feature request: Support Graphite metrics provider

[mdb]

Describe the feature

Thanks for your work on Flagger! At HBO Max, we're interested in experimenting with Flagger in support of progressive deployments, though many of our microservices' metrics currently live in Graphite.

Proposed solution

It would be great if Flagger supported a Graphite metrics provider (And we have some work in progress to add this support at https://github.com/HBOCodeLabs/flagger; stay posted for a PR soon 😃 )

Any alternatives you've considered?

We have considered making use of an already-supported metrics provider -- and eventually hope to make more use of Prometheus -- though the effort required for us to do so in the near term outweighs the effort required to add Graphite support to Flagger. Furthermore, others may benefit from Flagger Graphite support. 😃

[hiddeco]

Just a friendly heads-up that this issue isn't being ignored, but that @stefanprodan is enjoying well-deserved time off this week. He will probably get back to you next week. 🌻

[mdb]

Thanks for the update @hiddeco ! Hopefully we'll have an implementation PR'd by then =)