Jaeger: Support url for sampling.strategies file

[trondhindenes]

Requirement - what kind of business use case are you trying to solve?

We'd like to allow dev teams to control sampling strategies. This currently is quite involved since jaeger relies on a filesystem-file. In kubernetes this typically means a configMap volume, which requires us to restart all jaeger collector pods when the file is updated. Quite cumbersome.

I'd like Jaeger to support a sampling.strategies.url option, where the sampling strategies file was downloaded from a url. The cache timeout could be a separate parameter, or it could use the cache headers from the dowload to determine how often to retrieve updates.

Imho this would allow much easier changing of the sampling strategies, as we would be able to build a super-simple rest api to provide the json payload.

Problem - what in Jaeger blocks you from solving the requirement?

strategies.json is implemented as a filesystem-file only

Proposal - what do you suggest to solve the problem or improve the existing situation?

See requirement secion

Any open questions to address

[jpkrohling]

Looks interesting, do you want to give it a try?

[trondhindenes]

i'm not a go dev unfortunately, so implementing this is a bit out of reach for me atm.

[goku321]

Would like to try my hands on this.

[jpkrohling]

Go for it!