roger v2.1.0 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
Return whether the node is active or shutting down
Execute a given command on all nodes, and wait for all nodes to return their values
Execute a given command on all nodes, does not wait for their completion
Returns a specification to start this module under a supervisor
Return whether the node is connected to the AMQP broker
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Set node to inactive so it can no longer start new partitions
Unsubscribe from all queues - ie. stop listening for jobs
Link to this section Functions
Return whether the node is active or shutting down
Execute a given command on all nodes, and wait for all nodes to return their values
Execute a given command on all nodes, does not wait for their completion.
Returns a specification to start this module under a supervisor.
See Supervisor
.
Return whether the node is connected to the AMQP broker
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 {:ok, state, {:continue, continue}}
is similar to
{:ok, state}
except that immediately after entering the loop
the c:handle_continue/2
callback will be invoked with the value
continue
as first argument.
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 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 callingSupervisor.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 node to inactive so it can no longer start new partitions
Unsubscribe from all queues - ie. stop listening for jobs