This is the third implementation attempt. This time, rather than
broadcasting PeerAdd/Join requests to the whole cluster, we use the
consensus log to broadcast new peers joining.
This makes it easier to recover from errors and to know who exactly
is member of a cluster and who is not. The consensus is, after all,
meant to agree on things, and the list of cluster peers is something
everyone has to agree on.
Raft itself uses a special log operation to maintain the peer set.
The tests are almost unchanged from the previous attempts so it should
be the same, except it doesn't seem possible to bootstrap a bunch of nodes
at the same time using different bootstrap nodes. It works when using
the same. I'm not sure this worked before either, but the code is
simpler than recursively contacting peers, and scales better for
larger clusters.
Nodes have to be careful about joining clusters while keeping the state
from a different cluster (disjoint logs). This may cause problems with
Raft.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
The former RPC stuff had become a monster, really hard to have an overview
of the RPC api capabilities and with lots of magic.
go-libp2p-rpc allows to have a clearly defined RPC api which
shows which methods every component can use. A component to perform
remote requests, and the convoluted LeaderRPC, BroadcastRPC methods are
no longer necessary.
Things are much simpler now, less goroutines are needed, the central channel
handling bottleneck is gone, RPC requests are very streamlined in form.
In the future, it would be inmediate to have components living on different
libp2p hosts and it is way clearer how to plug into the advanced cluster rpc
api.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
