This corrects an annoying bug that had the system crash and burn on first start-up due to a race condition in service initialization, where the services were attempting to access the database before it was properly migrated.
A fix was in principle already in place, but it was running too late and did not prevent attempts to access the as-yet uninitialized database. Move the first boot check into the MainClass instead of the Service constructor.
The change also adds more appropriate docker dependencies to the services to fix rare errors resolving the hostname of the database.
Before the gRPC migration, the system would serve both public and internal requests over HTTP, but distinguish the two using path prefixes and a few HTTP Headers (X-Public, X-Context) added by the reverse proxy to prevent misconfigurations.
Since internal requests meaningfully no longer use HTTP, this convention is just an obstacle now, adding the need to always run the system behind a reverse proxy that rewrites the paths.
The change removes the path prefix, and updates the docker templates to reflect the change. This will require a migration for existing systems.
The previous behavior would listen to too many changes, and based on zookeeper and not curator assumptions about behavior, add an additional monitor on each invocation of each monitor, (which always trigger on service state changes), leading to each monitor re-registering and effectively doubling monitors in numbers whenever a service stopped or started, which in turn meant a lot of bizarre thrashing behavior even on changes in services that don't explicitly talk to each other.
This re-registering behavior is no longer done.
Netty and GRPC by default spawns an incredible number of threads on high-core CPUs, which amount to a fair bit of RAM usage.
Add custom executors that throttle this behavior.
Look, this will make the git history look funny, but trimming unnecessary depth from the source tree is a very necessary sanity-preserving measure when dealing with a super-modularized codebase like this one.
While it makes the project configuration a bit less conventional, it will save you several clicks every time you jump between modules. Which you'll do a lot, because it's *modul*ar. The src/main/java convention makes a lot of sense for a non-modular project though. This ain't that.
