Turning off IPv6 causes the tests to fail because the Go
`net.Listen()` function obtains a `[::]` address when using
a `localhost:0` bind address. Looking through the Go source
code, I don't see a good way to fix that.
This change adds a test flag to allow users to specify the
network name when running the test:
```sh
go test github.com/pilosa/pilosa/server -network tcp4
```
A configurable limit has been added to restrict the number of
mutating calls in a `pql.Query`. This is to prevents requests from
timing out from large queries.
The default is set to 5000 writes per request and is configurable
through the configuration file and the command line flags.
This mainly involved running `RecalculateCache()` on all fragments
in `TopN` tests. It seems these tests have been running as LRU
caches, and once we made `ranked` the default, they stopped working.
Some tests were affected by the change in partition number and
therefore the change in fragment to node mapping.
It is nested under "cluster" in the config, and it controls cluster membership
as well as broadcasting, so I think type is more appropriate. Also, brevity.
GossipNodeSet and GossipBroadcaster had a lot of cross dependency - I made them
the same object and had it implement all three interfaces (NodeSet, Broadcaster,
BroadcastReceiver).
I implmented an HTTPBroadcastReceiver which runs as as separate server.
BroadcastReceiver is a separate entity on the pilosa.Server object and is
started separately from broadcaster and nodeset. In the case of GossipNodeSet,
the broadcast receiver must be started before Open()ing the Nodeset, because it
doesn't actually start listening until Open() is called, but it needs the
handler set up before then.
server/server.go was heavily refactored to configure the new structs and
interfaces on the pilosa.Server object.
greatly simplifies Messenger, to the point of making it basically shell around
MessageBroker. Next stesp are to make the receiving of internal messages more
well-defined and behind an interface, remove/merge Messenger and MessageBroker,
and have the implementations of MessageBroker in separate packages.
