* Introduce ServiceManager and Refactor DAX Integration tests
The ServiceManager provides an interface with which to manage
featurebase (dax) services (mds, queryer, computer). It replaces the
confusing interface implementations in /dax/server/server.go (which
optionally used pointers to in-process objects to satisfy an interface)
with (for now) http implementations. The thought is that even if we're
running all services in-process, we should communicate between services
over http in order to mirror what we would do in a production
environment where the services are running on different nodes.
This batch of commits does quit a lot, most of which is captured here:
- Added `path` support to `dax.Address`. Address is now a string of the form [scheme]://[host]:[port]/[path].
- Added `Holder.directiveApplied` to determine (in tests) if the computer has completed applying the latest directive. This is somewhat temporary until we improve the mds-to-computer logic.
- Removed the "service prefix" code which was prepending client URL paths with the prefix. Instead, the serviceType (mds, queryer, computer[n] is now part of `dax.Address`).
- Removed, from the dax config, the top level `StorageMethod` and `StorageDSN` and now just have `MDS.Config.DataDir`.
- Added `Computer.Config.N` to specify the number of computers to run in-process.
- Moved the `pilosa.MDS` interface to `computer.Registrar`. This is an example of getting the interfaces defined in the right packages.
- Added `SnapshotTable()` method to the mds client (to align with its API).
- Changed `Balancer.AddJob()` to `Balancer.AddJobs()` to support, for example, adding 256 partitions in a single call. Refactored some of the naive Balancer to account for this.
- Added a `Seed` to the top-level config. It's not really useful because of package `crypto/rand`.
- Added an in-memory implementation of the DisCo interface and disabled etcd in a computer service.
- Create sepearte data-dirs for each in-process computer.
- Disabled grpc in dax.
- Modified the sql3 test definition format to support multiple insert steps and separate query results (to align with those steps).
* Changes necessary to get multiple computer instance running in-process
For now the config looks like this:
```
[computer]
run = true
n = 4
```
but we can probably just change that to be something like:
```
[computer]
run = 4
```
*Issues found running multiple "computers" in-process*
- grpc was trying to bind on the same port
- changed GRPCListener from `*net.TCPListener` to `net.Listener`
- created a nopListener and set to that for now (i.e. disabled grpc)
- etcd was starting more than once
- changed dax to use in-memory implementations of the disco interfaces (i.e. stop using etcd)
- IDAllocator (which uses boltdb) was trying to open the `idalloc.db` file more than once
- realized we have to set separate data-dirs for each holder. that fixed it.
* Port dax integration tests to ManagedCommand
* Modify Balancer-related methods like AddJob to AddJobs
There were (and still are) a lot of places where we were adding on job
at a time, even when we had a long list of jobs to add. This resulted in
every job add (for example adding 1 of 256 shards) taking ~40ms, or over
10s to create a keyed table. One reason was because each job add was
making multiple boltdb transactions.
* Port over more dax integration test stuff
* Add DirectiveApplied to signify that snapshot/writes have loaded.
We use this in tests to avoid using sleeps.
This should be considered temporary; we're going to need a more robust
solution for determining when a computer node is ready to serve complete
data.
* Finish porting dax integration tests
* Improve godocs
* Remove docker-based DAX integration tests.
* go mod tidy
* Move test/managed.go to avoid package conflicts
* Modify IDK integration tests to work with ServiceManager changes
This is really just computer -> computer0
And the MDS DataDir config change.
* cleanup found during review
* echo $CI_COMMIT_REF_SLUG in CI
* remove docker image arg, use build instead
(cherry picked from commit 2843f218bc)
* Rename dax.Shard to dax.VersionedShard
* Rename dax.Partition to dax.VersionedPartition
* Rename dax.FieldVersion to dax.VersionedField
* Rename go files to a standard
(cherry picked from commit 49d0e0fbc8)
