This is primarily to make the code a bit easier to reason about, and will reduce the level of indirection and data copying in the search-servi->query-service->index-service communication chain.
Adding new ranking parameters to the API and routing them through the system, in order to permit integration of the new position data with the ranking algorithm.
The change also cleans out several parameters that no longer filled any function.
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.
This is necessary as we use zookeeper to orchestrate first-time startup of the services, to ensure that the database is properly migrated by the control service before anything else is permitted to start.
Roll back to JDK 21 for now, and make Java version configurable in the root build.gradle
The project has run into no less than three distinct show-stopping bugs in JDK22, across multiple vendors, and gradle still doesn't fully support it, meaning you need multiple JDK versions installed.
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.
Cleaning out a lot of old junk from the code, and one thing lead to another...
* Build is improved, now constructing docker images with 'jib'. Clean build went from 3 minutes to 50 seconds.
* The ProcessService's spawning is smarter. Will now just spawn a java process instead of relying on the application plugin's generated outputs.
* Project is migrated to GraalVM
* gRPC clients are re-written with a neat fluent/functional style. e.g.
```channelPool.call(grpcStub::method)
.async(executor) // <-- optional
.run(argument);
```
This change is primarily to allow handling ManagedChannel errors, but it turned out to be a pretty clean API overall.
* For now the project is all in on zookeeper
* Service discovery is now based on APIs and not services. Theoretically means we could ship the same code either a monolith or a service mesh.
* To this end, began modularizing a few of the APIs so that they aren't strongly "living" in a service. WIP!
Missing is documentation and testing, and some more breaking apart of code.
To avoid having to either hard-code or manually configure service addresses (possibly several dozen), and to reduce the project's dependency on docker to deal with routing and discovery, the option to use [Zookeeper](https://zookeeper.apache.org/) to manage services and discovery has been added.
A service registry interface was added, with a Zookeeper implementation and a basic implementation that only works on docker and hard-codes everything.
The last remaining REST service, the assistant-service, has been migrated to gRPC.
This also proved a good time to clear out primordial technical debt from the root of the codebase. The 'service-client' library has been taken behind the barn and given a last farewell. It's replaced by a small library for managing gRPC channels.
Since it's no longer used by anything, RxJava has been removed as a dependency from the project.
Although the current state seems reasonably stable, this is a work-in-progress commit.
Refactored the GRPC Stub Pool for better handling of channel SHUTDOWN state. Any disconnected channels are now re-created before returning the stub.
The class was also renamed to GrpcChannelPool, as we no longer pool the stubs.
This change set updates the query APIs to enable the search service to add additional criteria, such as QueryStrategy and TemporalBias.
The QueryStrategy makes it possible to e.g. require a match is in the title of a result, and TemporalBias enables penalizing results that are not within a particular time period.
These options are added to the search interface. The old 'recent results' is modified to use TemporalBias, and a new filter 'Search In Title' is added as well.
The vintage filter is modified to add a temporal bias for the past.
* (executor-api) Make executor API talk GRPC
The executor's REST API was very fragile and annoying to work with, lacking even basic type safety. Migrate to use GRPC instead. GRPC is a bit of a pain with how verbose it is, but that is probably a lesser evil. This is a fairly straightforward change, but it's also large so a solid round of testing is needed...
The change set breaks out the GrpcStubPool previously residing in the QueryService, and makes it available to all clients.
ServiceId.name was also renamed to avoid the very dangerous clash with Enum.name().
The boilerplate needed for grpc was also extracted into a common gradle file for inclusion into the appropriate build.gradle-files.
The changeset also makes the control service responsible for flyway migrations. This helps reduce the number of places the database configuration needs to be spread out. These automatic migrations can be disabled with -DdisableFlyway=true.
The commit also adds curl to the docker container, to enable docker health checks and interdependencies.
