When doing tests, we create a ton of one-off clusters. This
turns out to be expensive and slow. Fixing it is surprisingly hard.
Fundamentally: If we're sharing clusters, we need to use different
indexes for each test, to avoid clashes. This changes index names.
As a side-effect, this reorders many partition-based things, like
the order keys are returned in. Thus, to fix this, we change a lot
of tests to no longer depend on the *order* in which strings are
returned.
Having done that, we can also discard the ModHasher behavior, since
that only existed to allow us to reliably predict partitioning.
The basic design is as follows: Instead of a cluster being a
[]*Command, a "shareable" cluster is now a []*Command plus some
flags, and a "cluster" is a pointer to a possibly-shared cluster,
plus a link to the specific test using this specific cluster,
and correspondingly, its test name suitably coerced to be a valid
index name prefix.
The "test.Cluster" object now has methods to allow retrieving an
index name, and also implemnts fmt.Formatter to let you use,
e.g., `%i` with it in Sprintf to get "the index name, plus an i".
(This works for everything but %p and %T.)
This allows us to consistently rework all the many things that
use index names in a persistent way.
We also have `MustUnshared` and `MustRunUnsharedCluster` methods
which allow us to specify that a given test needs its own cluster
for some reason. For instance, the tests that want to run backups
need their own isolated cluster, and the tests that want to close
or reopen nodes need their own cluster because a reopened cluster
won't have working GRPC for some reason.
On "closing" a shared cluster (actually the test-specific wrapper
that reflects a given sharing), we delete any indexes starting with
that test's index name prefix. Otherwise, the huge pile of open
indexes prevents `go test -race` from working on MacOS, where we
run out of address space too quickly.
This is fairly enormous but most of the individual changes are
fairly trivial things like replacing the string "i" with "c.Idx()".
We also tweaked a test that failed for me a couple of times to
not depend on sort order.
The http internal client's FragmentBlocks and Blockdata methods were being used
incorrectly, and incorrect respectively. One was not being passed a node URI by
monitorAntiEntropy, and the other was always using the defaultURI regardless of
what was passed to it. Antientropy was doubling not working because of this. I
think this crept in pretty recently, so hasn't actually affected anyone.
I exposed a SyncData method on Server so that we can invoke the anti entropy
task manually instead of trying to set up the interval so that it will run and
then sleeping and waiting for it to run. Now that this test works the way it
does, the other anti entropy test is obsolete, and I deleted it.
cluster.open waits for node to join cluster if it is not the coordinator, and
currently this relies on having the http handler able to receive messages, so
handler needs to be started first.
