This is a giant cleanup of the etcd code. The earlier version was
written when I was less experienced with golang.
This is still not perfect, and does contain some races, but at least
it's a decent base to start from. The automatic elastic clustering
should be considered an experimental feature. If you need a more
battle-tested cluster, then you should manage etcd manually and point
mgmt at your existing cluster.
Part of this was rotten, and not fully functional. This fixes the rot,
adds some tests, and improves the type checking that occurs when sending
and receiving values. In addition, a significant portion of this happens
at compile time.
There is still more work to be done here, but this should get us a good
chunk of the way for now.
This adds back the retry loop around Process. This is done as a
separate commit so you can more easily see the logic of the retry magic
This commit is similar but different to the earlier commit adding retry
around Watch.
The engine core had some unfortunate bugs that were the result of some
early design errors when I wasn't as familiar with channels. I've
finally rewritten most of the bad parts, and I think it's much more
logical and stable now.
This also simplifies the resource API, since more of the work is done
completely in the engine, and hidden from view.
Lastly, this adds a few new metaparameters and associated code.
There are still some open problems left to solve, but hopefully this
brings us one step closer.
It's plausible that we send on a closed channel if we're running a back
poke and it tries to send a poke on something that has already closed.
If it detects this condition, it will exit.
Unfortunately, it's not clear if the wait group will protect this case,
but hopefully this will hold us until we can re-write the needed parts
of the engine.
Occasionally when a back poke happens downstream of an upstream vertex
which has already exited, it could get back poked, which would cause a
panic. This moves the deletion of the state struct until the entire
graph has completed so that it won't panic. It doesn't matter if a back
poke is lost, we're shutting down or pausing, and in this scenario it
can be lost.
Somewhere after the engine re-write we seem to have regressed and
converge early even if some resource is dirty. This adds an additional
timer so that we don't start the individual resource converged countdown
until our state is okay.
This allows golang tests to be marked as root or !root using build tags.
The matching tests are then run as expected using our test runner.
This also disables test caching which is unfriendly to repeated test
running and is an absurd golang default to add.
Lastly this hooks up the testing verbose flag to tests that accept a
debug variable.
These tests aren't enabled on travis yet because of how it installs
golang.
This giant patch makes some much needed improvements to the code base.
* The engine has been rewritten and lives within engine/graph/
* All of the common interfaces and code now live in engine/
* All of the resources are in one package called engine/resources/
* The Res API can use different "traits" from engine/traits/
* The Res API has been simplified to hide many of the old internals
* The Watch & Process loops were previously inverted, but is now fixed
* The likelihood of package cycles has been reduced drastically
* And much, much more...
Unfortunately, some code had to be temporarily removed. The remote code
had to be taken out, as did the prometheus code. We hope to have these
back in new forms as soon as possible.
