This commit introduces an api.Cid type and replaces the usage of cid.Cid
everywhere.
The main motivation here is to override MarshalJSON so that Cids are
JSON-ified as '"Qm...."' instead of '{ "/": "Qm....." }', as this "ipld"
representation of IDs is horrible to work with, and our APIs are not issuing
IPLD objects to start with.
Unfortunately, there is no way to do this cleanly, and the best way is to just
switch everything to our own type.
This commit continues the work of taking advantage of the streaming
capabilities in go-libp2p-gorpc by improving the ipfsconnector and pintracker
components.
StatusAll and RecoverAll methods are now streaming methods, with the REST API
output changing accordingly to produce a stream of GlobalPinInfos rather than
a json array.
pin/ls request to the ipfs daemon now use ?stream=true and avoid having to
load the full pinset map on memory. StatusAllLocal and RecoverAllLocal
requests to the pin tracker stream all the way and no longer store the full
pinset, and the full PinInfo status slice before sending it out.
We have additionally switched to a pattern where streaming methods receive the
channel as an argument, allowing the caller to decide on whether to launch a
goroutine, do buffering etc.
This commit introduces the new go-libp2p-gorpc streaming capabilities for
Cluster. The main aim is to work towards heavily reducing memory usage when
working with very large pinsets.
As a side-effect, it takes the chance to revampt all types for all public
methods so that pointers to static what should be static objects are not used
anymore. This should heavily reduce heap allocations and GC activity.
The main change is that state.List now returns a channel from which to read
the pins, rather than pins being all loaded into a huge slice.
Things reading pins have been all updated to iterate on the channel rather
than on the slice. The full pinset is no longer fully loaded onto memory for
things that run regularly like StateSync().
Additionally, the /allocations endpoint of the rest API no longer returns an
array of pins, but rather streams json-encoded pin objects directly. This
change has extended to the restapi client (which puts pins into a channel as
they arrive) and to ipfs-cluster-ctl.
There are still pending improvements like StatusAll() calls which should also
stream responses, and specially BlockPut calls which should stream blocks
directly into IPFS on a single call.
These are coming up in future commits.
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.
