* 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
The special case of Starting allowed us to make sure every node in a
cluster waited for the whole cluster to come up, but caused problems
later if a node died and came back. We drop the Starting state for
clusters, treating a STARTING node as equivalent to an UNKNOWN (or
DOWN) node for purposes of cluster state, so clusters will go from
Down to Degraded to Normal as nodes come up. We now wait for the
Normal state during initial bringup. We would previously have accepted
Degraded, if you could reach it, for instance if a node came up and
then went down again before another node finished starting, but I'm
pretty sure that was unintentional.
This solves a problem where while a node was down, we'd accept
queries that we could handle in a degraded state, but then we'd
*stop* accepting them when the node started coming back up.
enriched metadata for tables
added support for the concept of a table and field owners in metadata; mechanism to derive owner from http request metadata; metadata for table description
The root problem this is attempting to address is sporadic
weird cases in which etcd mistakenly thinks it's down even when
it's up. I am not confident that this is addressed, but there's
a reasonable chance that it is, and I can't trigger it at the
moment, but it was always sporadic, so that doesn't prove much.
There's a lot going on here, and it comes into roughly three
categories.
First: Dropping unused/unneeded code. There's a lot of leftover
bits from the initial development and refactoring of this.
Second: Unifying and shuffling some of the design. We had
multiple interfaces which are functionally impossible to
usefully implement separately, so they're combined together,
and in some cases, moved.
Third: Streamlining logic and simplifying design choices.
This is combined into one commit because the changes are
thoroughly entertwined with each other and you can't usefully
break most of them out.
Also, a bunch of test coverage for most of these changes.
Big changes:
We merge the topology and disco packages. The topology and disco
packages being separate creates a complicated tangle of problems
and dependencies. The fundamental problem, approximately, is that
topology.Node has to track disco.NodeState.
There's three core interfaces interacting here:
topology.Noder (maintains list of nodes)
disco.Stator (maintains the state of a node)
disco.Metadator (stores, possibly retrieves, node metadata)
But the node state mantained by the Noder *is* the set of node
metadata, plus state updates produced by Stators. The only actual
non-trivial and usable implementation of these interfaces is a single
thing which implements all three, and in which the implementations
share a single backend data source which they are all modifying.
But you can't move Noder into disco, because Noder has to refer
to topology.Node, but topology.Node refers to disco.
Solution: First, merge these two packages. Second, merge these
three interfaces, to provide a single interface which is more
clear about the fact that (metadator.)SetMetadata() and
(stator.)Started() are both changing the output we'll get from
(noder.)Nodes().
We rework the node state tracking.
We have this nodeStates map which is almost unused. Really, we
don't need it at all. Every node's state is either its last heartbeat
state or "Unknown", so we simplify this a bit. Also, we ensure that
the populateNodeStates function itself is yielding the sorted nodes
list, so we don't have to be as worried about possible later lookups
of sortedNodes happening outside a lock. We also add diagnostics
for deleting nodes from the metadata list (this should never happen),
and try to track heartbeat state more closely.
This is *probably* what fixes the underlying reported problem,
if anything did.
Still an open issue: Make heartbeat state changes aware of when
they're talking about *this* node and possibly not try to
mark it down? Except this may have a flaw: That would result in
each node disagreeing with other nodes in etcd about the state
of that node in the failure cases, and undermine the point of
using etcd to keep these states consistent.
We reduce the number of contexts and cancelfuncs in the etcd wrapper.
We create a shared context for the non-etcd.embed children of our
etcd wrapper, the heartbeat/keepalive and the node watcher, so we
can cancel that one context and cancel all of those at once, so
we don't need to separately track a function to call to cancel
the watch, AND be closing another channel. Also, our shutdown
now propagates automatically to the various etcd API calls we've
made for things like the node watcher and keepalive calls.
We still need to watch that channel in watchNodesOnce, though,
because apparently the watch doesn't yield an error even if the
context calling it is canceled. Whee.
This should reduce the risk of ending up in an inconsistent state,
and also the Close() function is probably idempotent now.
Smaller changes:
* Remove config-generators that existed to generate etcd
configs but were used only for tests that no longer exist
or make sense.
* Move the logic to generate etcd configs into the etcd
package, instead of the "testing" subpackage. This allows
us to write a self-contained config generator for
clusters where the nodes know about each other, but do
this just with etcd, not with full featurebase servers.
* Move the thing generating `fake:%d` socket names into
the etcd package, which is the only place we use it.
Also simplify it slightly.
* Don't panic on invalid URLs, report errors from them.
* At least try to use etcd's config.Validate functionality.
It's underdocumented, so we're not sure what it will report,
but at least if it does we'll get reports from it and
know what they are?
* Try to handle CompactRevision errors from watches more
correctly -- after a CompactRevision, any future attempt
to watch from a lower revision will necessarily fail, so
we adjust our target revision up. We don't have good
testing for this.
* Drop the Metadata() method (that used to be in Metadator)
because nothing ever used it and it didn't make much sense
to try.
* Convert SetMetadata from taking an arbitrary json blob
to taking the only data that would ever be valid since
we always use it to extract node information anyway.
* Drop several unused functions, unexport things only used
internally.
* Replace Started() with SetState("STARTED"), allowing us
to write tests that mess with states. We weren't really thinking
carefully about state transitions sometimes and now it's much
easier to do that thinking.
* Stop leaving stray localhost:2380 and localhost:2379 in
our embed config. We still sometimes see peer requests from
those and I honestly don't know why, but at least it should
be rarer.
We had two different, incompatible-with-each-other, and both
individually broken, partial implementations of resizing logic.
There's the original pre-etcd resize, and then the etcd resize,
and neither works, but there's conflicts between the ways they
don't work.
No attempt to fix this is likely to yield decent results, so
instead, we yank them both out entirely, so if we decide to
implement resizing (which we will) we won't be confused by
stray code pertaining to resizing that's not really hooked
up to anything.
We're leaving the resize messages in protobuf to avoid renumbering
protobuf messages. We rename some of our message types to UNUSED0,
etcetera, so that any code still using the old names won't
compile, to make sure we get rid of it, but we can't just drop
the numbers without breaking rolling restart.
The Resize_AddNode tests are removed not just because we don't
have resizing, but because they were completely broken anyway
and never worked at all. But there's no reason to fix them because
they exist to fix the functionality we didn't have and are now
removing the vestigial remains of.
We also drop the one usage of the AddNode function of Noder, because
it was used only by one test code fragment that was creatincg clusters,
and that can be done more correctly. There were no other call sites
at all.
We mark the monitorAntiEntropy function to be ignored by
code coverage because it's not actually being covered. There's
a separate ticket for removing that entirely.
i used this script, a little clunky but it got the job done
```bash
for file in `find . -type f -print | grep '\.go'`; do
sed '1,/^\/\/ limitations under the License.$/d' $file > $file.tmp;
result=`cat $file.tmp`
if [[ result != "" ]]; then
gofmt $file.tmp &> /dev/null;
if [[ $? == 0 ]]; then
mv $file.tmp $file && gofmt -w $file;
else
rm $file.tmp;
fi
else
rm $file.tmp;
fi
done
```
port mapper gives out ports from 63000-65000 for the tests
fix another race
http test uses port.MustGetPort
rbf: remove :0 port request
ocd happy
test fix for grpc listener address already in use
test/disco allocates BindGRPC port from the port mapper
dump stack on each GetPort
verify each port is usable right away
server/config.go has Config.Validate() now
panic if gossip port is 0. validate server.Config
fix another gossip port 0
builds
quiet, don't dump stack on each port alloc
builds
happy linter
even gossip fallback should not be zero but rather use the port mapper
