Adds support for default attributes

[jcchavezs]

A common use case is that users can pass default attributes to instrumentation at different levels, e.g.:

• https://github.com/openzipkin/brave/blob/f89723df407e2b85dd7e6700ab574b4fa5bdae94/brave/src/test/java/brave/features/handler/DefaultTagsTest.java#L32
• https://github.com/openzipkin/zipkin-go/blob/master/middleware/http/server.go#L42
• Allow adding arbitrary tags on span openzipkin/zipkin-js#502
• recoding default tags on server instrumentation openzipkin/zipkin-js#302

We can allow static tags being passed directly from code and also over env vars:

message AgentConfig {
    ...

    // defaultTags accept a map of tags that will be added on every span
    map<string, string> defaultTags = 4;
}

Ping @hypertrace/agent-maintainers

[pavolloffay]

LGTM, for the name I would consider using attributes, but the HT uses tags in the search bar so I am not sure.

[davexroth]

agreed, we should standardize on attributes. And I thought we had gone through and updated HT to use attributes, but maybe we missed some places. We should fix that.

[jcchavezs]

Yeah, makes sense to use attributes.

…

On Thu, 12 Nov 2020, 20:52 David Roth, ***@***.***> wrote: agreed, we should standardize on attributes. And I thought we had gone through and updated HT to use attributes, but maybe we missed some places. We should fix that. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#21 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAXOYAVBWQ33V6RXGRSQ3RDSPQ4GHANCNFSM4TTVOP3A> .