roger v2.0.1 Roger.System View Source

Listener for system-wide events.

On the AMQP side, the systemchannel declares a fanout exchange called ‘system’ and adds a private queue to it, which it consumes.

Link to this section Summary

Functions

active?()

Return whether the node is active or shutting down

call(command, args \\ nil)

Execute a given command on all nodes, and wait for all nodes to return their values

cast(command, args \\ nil)

Execute a given command on all nodes, does not wait for their completion

child_spec(arg)

Returns a specification to start this module under a supervisor

connected?()

Return whether the node is connected to the AMQP broker

init(list)

Invoked when the server is started. start_link/3 or start/3 will block until it returns

set_inactive()

Set node to inactive so it can no longer start new partitions

unsubscribe_all()

Unsubscribe from all queues - ie. stop listening for jobs

Link to this section Functions

active?()

Return whether the node is active or shutting down

call(command, args \\ nil)

Execute a given command on all nodes, and wait for all nodes to return their values

cast(command, args \\ nil)

Execute a given command on all nodes, does not wait for their completion.

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

connected?()

Return whether the node is connected to the AMQP broker

init(list)

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

args is the argument term (second argument) passed to start_link/3.

Returning {:ok, state} will cause start_link/3 to return {:ok, pid} and the process to enter its loop.

Returning {:ok, state, timeout} is similar to {:ok, state} except handle_info(:timeout, state) will be called after timeout milliseconds if no messages are received within the timeout.

Returning {:ok, state, :hibernate} is similar to {:ok, state} except the process is hibernated before entering the loop. See c:handle_call/3 for more information on hibernation.

Returning :ignore will cause start_link/3 to return :ignore and the process will exit normally without entering the loop or calling c:terminate/2. If used when part of a supervision tree the parent supervisor will not fail to start nor immediately try to restart the GenServer. The remainder of the supervision tree will be (re)started and so the GenServer should not be required by other processes. It can be started later with Supervisor.restart_child/2 as the child specification is saved in the parent supervisor. The main use cases for this are:

The GenServer is disabled by configuration but might be enabled later.
An error occurred and it will be handled by a different mechanism than the Supervisor. Likely this approach involves calling Supervisor.restart_child/2 after a delay to attempt a restart.

Returning {:stop, reason} will cause start_link/3 to return {:error, reason} and the process to exit with reason reason without entering the loop or calling c:terminate/2.

Callback implementation for GenServer.init/1.

set_inactive()

Set node to inactive so it can no longer start new partitions

unsubscribe_all()

Unsubscribe from all queues - ie. stop listening for jobs