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 the online case we were unnecessarily loading the configuration from IPFS, a very
slow operation if IPFS is very busy (when syncing).
For the offline case, we required IPFS to be online (for remote
configurations) slow things down as well and is uncovenient. Instead, simply
open the database with default parameters and list it.
Fixes#865.
This makes the necessary changes so that consensu is selected on "init" with a
flag set, by default, to "crdt". This generates only a "crdt" or a "raft"
section, not both.
If the configuration file has a "raft" section, "raft" will be used to start
the daemon. If it has a "crdt" section, "crdt" will be used. If it has none or
both sections, an error will happen.
This also affects "state *" commands, which will now autoselect how to work
from the existing configuration.
* Daemon: support remote configuration
This:
* Adds support for fetching the configuration from a remote HTTP location:
`ipfs-cluster-service init http://localhost:8080/ipfs/Qm...` will instruct
cluster to read the configuration file from ipfs on start (potentially making
use of ipns and dnslink).
This is done by creating a `service.json` like `{ "source": <url> }`.
The source is then read when loading that configuration every time the daemon starts.
This allows to let users always use a mutating remote configuration, potentially
adding/removing trusted peers from the list or adjusting other things.
* Configuration and state helpers from ipfs-cluster-service have been extracted
to its own cmdutils package. This will help supporting something like an
`ipfs-cluster-follow` command in the next releases.
* Allows to disable the rest api by not defining it in the configuration (I thought
this was already so, but apparently only affected the ipfsproxy).
* Removes informer/allocator configurations from the daemon (--alloc). No one used
a non default pair. In fact, it was potentially buggy to use the reposize one.
