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defprotocol SNet.Group do
@moduledoc"""
A group is a specification of a bunch of peers we want and accept to talk to
about some things. It supports a number of abstract operations for finding peers,
broadcasting/gossiping, authenticating, etc.
"""
@doc"""
Find new peers for this group, open connections and notify us when connections are open.
Launches background processes if necessary, returns immediately.
"""
def init_lookup(group, notify_to)
@doc"""
Get all currently open connections to peers in this group.
"""
def get_connections(group)
@doc"""
Broadcast a message to peers of the group.
Will send to at most nmax peers, so this is a good primitive for gossip.
"""
def broadcast(group, msg, nmax \\ 10)
@doc"""
Check if a peer is allowed to participate in this group.
"""
def in_group?(group, conn_pid, auth)
end
defmodule SNet.PubShardGroup do
defstruct [:id]
defimpl SNet.Group do
def init_lookup(%SNet.PubShardGroup{id: id}, _notify_to) do
# For now: ask all currently connected peers and connect to new peers we know of
spawn fn ->
for {_, pid, _} <- SNet.Manager.list_connections do
GenServer.cast(pid, {:send_msg, {:interested, [id]}})
end
for peer_info <- Shard.Manager.get_shard_peers id do
if SNet.Manager.get_connections_to peer_info == [] do
SNet.Manager.add_peer(peer_info) # TODO callback when connected
end
end
end
# TODO: use a DHT to find peers
end
def get_connections(%SNet.PubShardGroup{id: id}) do
Shard.Manager.get_shard_peers(id)
|> Enum.map(&(SNet.Manager.get_connections_to(&1)))
|> Enum.filter(&(&1 != []))
|> Enum.map(fn [{pid, _auth}|_] -> pid end)
end
def broadcast(group, msg, nmax) do
%SNet.PubShardGroup{id: id} = group
nsent = get_connections(group)
|> Enum.shuffle
|> Enum.take(nmax)
|> Enum.map(&(GenServer.cast(&1, {:send_msg, msg})))
|> Enum.count
if nmax - nsent > 0 do
Shard.Manager.get_shard_peers(id)
|> Enum.filter(&(SNet.Manager.get_connections_to(&1) == []))
|> Enum.shuffle
|> Enum.take(nmax - nsent)
|> Enum.map(&(SNet.Manager.send(&1, msg)))
end
end
def in_group?(%SNet.PubShardGroup{id: _id}, _peer_pid, _auth) do
true # No access control
end
end
end
defmodule SNet.PrivGroup do
defstruct [:pk_list]
defimpl SNet.Group do
def init_lookup(%SNet.PubShardGroup{id: id}, notify_to) do
# TODO
end
def get_connections(%SNet.PubShardGroup{id: id}) do
# TODO
end
def broadcast(group, msg, nmax) do
end
def in_group?(%SNet.PubShardGroup{id: _id}, peer_pid, auth) do
# TODO
end
end
end
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