roger v2.4.1 Roger.Partition.Global View Source
Coordinates the global Roger partition state
Each Roger partition has a single place where global state is kept. Global state (and global coordination) is needed for the following things:
Job cancellation; when cancelling a job, we store the job ID globally; when the cancelled job is started, we check the job id against this list of cancelled ids.
Queue keys; some jobs dictate that they cannot be queued when there is already a job queued with an identical queue key; if so, the job fails to enqueue.
Execution keys; jobs which have the same execution key cannot be executed concurrently and need to wait on one another.
Pause states; it is globally stored which queues are currently paused.
The per-partition Global process stores all this information. It provides hooks to persist the information between partition / node restarts. By default, the global state is loaded from and written to the filesystem, but it is possible to override the persister, like this:
config :roger,
persister: Your.PersisterModule
The persister module must implement the
Roger.Partition.Global.StatePersister
behaviour, which provides
simple load and save functions.
Link to this section Summary
Functions
Mark a job id as cancelled
Check whether a given job id has been marked cancelled
Returns a specification to start this module under a supervisor
Check whether a given execution key has been set
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Get the set of paused queues for the given partition_id
Cluster-wide pausing of the given queue in the given partition_id
Cluster-wide pausing of the given queue in the given partition_id
Check whether a given queue key has been marked enqueued
Remove the given execution key
Remove a given queue key
Link to this section Functions
Mark a job id as cancelled.
This does not check for the validity of the job id. The job will not be removed from the queue, but instead will be removed as soon as it’s dequeued.
When a job is currently executing, the process of a running job will be killed.
Check whether a given job id has been marked cancelled
Returns a specification to start this module under a supervisor.
See Supervisor
.
Check whether a given execution key has been set
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
.
Get the set of paused queues for the given partition_id.
Cluster-wide pausing of the given queue in the given partition_id.
Cluster-wide pausing of the given queue in the given partition_id.
Check whether a given queue key has been marked enqueued
Remove the given execution key
Remove a given queue key