Shared GenServer poll loop for mesh strategies.
Every polling_interval it asks the strategy module for the current peers
(discover/1), filters them down to the online ones that belong to the
cluster, and hands the resulting node names to
Cluster.Strategy.connect_nodes/4. Discovery runs in this process and the
next poll is scheduled only once it returns, so a daemon slower than the
interval delays polls instead of piling them up.
Discovery failures are logged and retried on the next interval; they never
crash the strategy. Disconnects are left to the mesh and :net_kernel.
A control-plane interruption can mark a peer offline while its direct data
path and Erlang connection remain healthy, so a poll never tears down an
established connection from a transient daemon view. net_ticktime closes
a connection whose data path is actually gone.
Summary
Callbacks
Returns the current mesh peers, or an error message when the daemon cannot be queried.
Functions
Returns a specification to start this module under a supervisor.
Filters peers to online cluster members and maps them to node names.
Starts the poll loop for strategy (a module implementing discover/1).
Callbacks
@callback discover(LibclusterMesh.Config.t()) :: {:ok, [LibclusterMesh.Peer.t()]} | {:error, String.t()}
Returns the current mesh peers, or an error message when the daemon cannot be queried.
Functions
Returns a specification to start this module under a supervisor.
See Supervisor.
@spec nodes_for([LibclusterMesh.Peer.t()], LibclusterMesh.Config.t()) :: [node()]
Filters peers to online cluster members and maps them to node names.
The local node is excluded (some daemons include it in their peer output), and duplicates are removed.
iex> peers = [
...> %LibclusterMesh.Peer{ip: "100.64.0.7", hostname: "myapp-2"},
...> %LibclusterMesh.Peer{ip: "100.64.0.3", hostname: "laptop"},
...> %LibclusterMesh.Peer{ip: "100.64.0.9", hostname: "myapp-3", online?: false}
...> ]
iex> config = %LibclusterMesh.Config{node_basename: "myapp", hostnames: ["myapp-"], cli: "ztlctl"}
iex> LibclusterMesh.Poller.nodes_for(peers, config)
[:"myapp@100.64.0.7"]@spec start_link( module(), String.t(), [Cluster.Strategy.State.t()], LibclusterMesh.Config.opts() ) :: GenServer.on_start()
Starts the poll loop for strategy (a module implementing discover/1).
Called by the strategy's start_link/1 with the args libcluster passes in.
opts are forwarded to LibclusterMesh.Config.new!/3, declaring which
config keys the strategy supports. Raises ArgumentError when the topology
config is invalid.