piton v0.4.0 Piton.Pool View Source

Piton.Pool is a GenServer which will be on charge of a pool of Piton.Ports.

Piton.Pool will launch as many Python processes as you define in pool_number and it will share them between all the request (executions) it receives. It is also protected from Python exceptions, therefore, if a Python code raises an exception that can close the port, a new one will be opened and added it to the pool.

Start a Pool

  {:ok, pool} = Piton.Pool.start_link([module: MyPoolPort, pool_number: pool_number], [])

The arguments has to be in a Keyword List and it has to contain:

module: Module which has to `use Piton.Port`
pool_number: number of available Pythons.

Run a Python code using the pool

  Piton.Pool.execute(pid_of_the_pool, elixir_function, list_of_arguments_of_elixir_function)

Timeout

Piton.Port.execution function has a timeout, this timeout will be passes as timeout to the Piton.Port.execution function.

Link to this section Summary

Functions

child_spec(arg)

Returns a specification to start this module under a supervisor

execute(pid, python_function, python_arguments, timeout \\ 5000)

It will execute the arguments in the given function of the given module using the given pool of ports

get_number_of_available_ports(pid)

It will return the number of available ports

get_number_of_waiting_processes(pid)

It will return the number of processes that are waiting for an available port

init(list)

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

start_link(args, opts)

Link to this section Functions

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

execute(pid, python_function, python_arguments, timeout \\ 5000)

execute(pid(), atom(), list(), timeout()) :: {:ok, any()} | {:error, any()}

It will execute the arguments in the given function of the given module using the given pool of ports.

get_number_of_available_ports(pid)

get_number_of_available_ports(pid()) :: integer()

It will return the number of available ports.

get_number_of_waiting_processes(pid)

get_number_of_waiting_processes(pid()) :: integer()

It will return the number of processes that are waiting for an available port.

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.

start_link(args, opts)