This commit adds badger v3 support as datastore backend for IPFS Cluster.
Badgerv3 has a number of improvements over v1, particularly around
compaction. It is significantly more modern and should behave better in
general (some testing is pending).
This takes advantage of go-ds-badger "auto-gc" feature.
It will run a GC cycle made of multiple GC rounds (until it cannot GC more)
automatically. The behaviour is enabled by default in the configuration and
can be disabled by setting "gc_interval" to "0m". Hopefully this prevents
badger datastores from growing crazy.
Badger can take 1000x the amount of needed space if not GC'ed or compacted
(#1320), even for non heavy usage. Cluster has no provisions to run datastore
GC operations and while they could be added, they are not ensured to
help. Improvements on Badger v3 might help but would still need to GC
explicitally.
Cluster was however designed to support any go-datastore as backend.
This commit adds LevelDB support. LevelDB go-datastore wrapper is mature, does
not need GC and should work well for most cluster usecases, which are not
overly demanding.
A new `--datastore` flag has been added on init. The store backend is selected
based on the value in the configuration, similar to how raft/crdt is. The
default is set to leveldb. From now on it should be easier to add additional
backends, i.e. badgerv3.
For simplicity, I haven't exposed the entire
badger config. Also, due to go default values and
the badger implementation, I have had to extract the
two loading mode config values so we can determine
whether it has actually has been set by the user in
the json config file.
License: MIT
Signed-off-by: Adrian Lanzafame <adrianlanzafame92@gmail.com>
This adds a new "crdt" consensus component using go-ds-crdt.
This implies several refactors to fully make cluster consensus-component
independent:
* Delete mapstate and fully adopt dsstate (after people have migrated).
* Return errors from state methods rather than ignoring them.
* Add a new "datastore" modules so that we can configure datastores in the
main configuration like other components.
* Let the consensus components fully define the "state.State". Thus, they do
not receive the state, they receive the storage where we put the state (a
go-datastore).
* Allow to customize how the monitor component obtains Peers() (the current
peerset), including avoiding using the current peerset. At the moment the
crdt consensus uses the monitoring component to define the current peerset.
Therefore the monitor component cannot rely on the consensus component to
produce a peerset.
* Re-factor/re-implementation of "ipfs-cluster-service state"
operations. Includes the dissapearance of the "migrate" one.
The CRDT consensus component defines creates a crdt-datastore (with ipfs-lite)
and uses it to intitialize a dssate. Thus the crdt-store is elegantly
wrapped. Any modifications to the state get automatically replicated to other
peers. We store all the CRDT DAG blocks in the local datastore.
The consensus components only expose a ReadOnly state, as any modifications to
the shared state should happen through them.
DHT and PubSub facilities must now be created outside of Cluster and passed in
so they can be re-used by different components.
