Zipkin 1.27

Zipkin 1.27 moves the UI under the path /zipkin, allows listening on multiple Kafka topics and improves Cassandra 3 support.

The Zipkin UI was formerly served from an unmodified server as the base path. We've had folks ask for a year in various ways to have this under a subpath instead. We decided to move the UI under /zipkin as it matched most users' requirements and was easiest for our single-page app to route. Thanks to @eirslett @danielkwinsor and @neilstevenson for help with implementation and testing.

We recently added Kafka 0.10 support. This version includes the ability to listen on multiple topics, something you might do if you have environments where spans come from different sources. Thanks to @danielkwinsor for implementation and @dgrabows for review, we now support this by simply comma-delimiting the topic. Note: there are some gotchas if you are considering migrating from Kafka 0.8 to 0.10. Thanks to @fedj for noting something you might run into.

Some of you may using the experimental "cassandra3" storage type. We had a serious glitch @llinder found where blocking could occur on a query depending on the count of results retuned. Not only did Lance fix the glitch, but also added testcontainers to ensure clean, docker-based integration tests run on every PR.

Finally, Zipkin 1.27 fixes a number of broken windows. Thanks @NithinMadhavanpillai for adding a test to help us fix a bad data bug parsing dependencies, @fgcui1204 for finding out why service names sometimes cut off in the UI, @ImFlog for backfilling docs about how ports can be specified in cassandra and @joel-airspring for fixing a few distracting glitches in our build.