Depends on protobuf-c 1.3

[ringerc]

The build seems to depend on protobuf-c 1.3 or newer, since it refers to protobuf-gen-c, which AFAICS was added in 1.3. (See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221572).

I've tweaked it to build on 1.2 too. Unclear how important that really is, since RHEL seems to carry 1.0.2 and EL6 EPEL has 0.15 (!). But it's cheap and easy.

[isaachier]

protobuf-gen-c vs. protoc-c is more of a fix for Hunter than for anything else. I can change it if you'd like. As long as it supports proto3 I'm happy. For the record, the schema for messages is about to change really soon (see jaegertracing/jaeger#856).

[ringerc]

I have some more changes pending in my tree, so don't work on it yet. I'm integrating Travis support for HUNTER_ENABLED=0, fixing protobuf finding, etc.

It seems like really the Hunter CMake files should expose a protobuf-c::protoc-c target and fail to do so, but it's easily worked around.

[ringerc]

(You can see my WIP in my https://github.com/2ndquadrant/jaeger-client-c master branch, but beware it's full of CI-fixit spam commits and will be brutally squashed and rebased soon)

[ringerc]

... and I won't waste time seeing if I can make it build with the packaged libprotobuf-c0-dev (0.15) in Ubuntu Trusty.

protobuf will have to be fetched from a PPI or backports or the like. It's amazingly poorly packaged I'm finding - not in EPEL for example. Oh well, at least it's simple to install and reasonably backward compatible.

I've already confirmed it's fine on 1.2 though, just needs a fallback implementatoin to use protoc-c that I've added.

[ringerc]

1.2 does not support proto3. Only protobuf-c 1.3.0 does. jaeger-client-c currently works fine with protobuf 1.2, but I'm assuming you plan to move to proto3?

So that makes this a dependency that's impossible to satisfy on anything but bleeding edge systems except by bundling it.

Not the end of the world, since it can be a private copy. Ugly, but workable. I now see why you have the code in scripts/install-deps.sh to download and build a local copy of protobuf-c. I've switched it off when hunter is enabled, but am using it for the new non-hunter CI build.

[ringerc]

Addressed in #3

[isaachier]

I've commented in #3 about this as well.