roger v2.1.0 Roger.Partition View Source

Per-node partition registry

Roger implements multi-tenancy by dividing all its work between different “Partitions”. Each partition is identified by a unique ID. Partitions consist of a list of queues, which are defined by its type (an atom) and a max_workers value which sets the concurrency level. The RabbitMQ queue name is constructed of the partition ID + the queue type.

To spread out the work, partitions can be started in the cluster on multiple nodes. The partition’s queue configuration can be different between nodes - i.e. some node might be able to handle more concurrency than others.

Within the cluster, there is one global process (Roger.Partition.Global) which manages the partition’s state. In it, it manages job’s uniqueness, states of paused queues, et cetera.

Link to this section Summary

Types

queue_def()

Functions

child_spec(arg)

Returns a specification to start this module under a supervisor

init(list)

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

reconfigure(id, queues)

Reconfigure the given Roger partition

safe_stop(id)

Stop the parition of accepting new jobs so it can finish of the remaining jobs

start(id, queues)

Start a Roger partition

stop(id)

Stop the given Roger partition

Link to this section Types

queue_def()

queue_def() :: {id :: String.t(), max_workers :: non_neg_integer()}

Link to this section Functions

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

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 {: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 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.