View Source FLAME.Pool (flame v0.1.8)

Manages a pool of FLAME.Runner's.

Pools support elastic growth and shrinking of the number of runners.

Examples 

children = [
  ...,
  {FLAME.Pool, name: MyRunner, min: 1, max: 10, max_concurrency: 100}
]

See start_link/1 for supported options.

TODO

[ ] interface to configure min/max at runtime

Summary

Functions

call(name, func, opts \\ [])

Calls a function in a remote runner for the given FLAME.Pool.

cast(name, func)

Casts a function to a remote runner for the given FLAME.Pool.

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

place_child(name, child_spec, opts)

See FLAME.place_child/3 for more information.

start_link(opts)

Starts a pool of runners.

Functions

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call(name, func, opts \\ [])

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Calls a function in a remote runner for the given FLAME.Pool.

See FLAME.call/3 for more information.

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cast(name, func)

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Casts a function to a remote runner for the given FLAME.Pool.

See FLAME.cast/2 for more information.

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child_spec(init_arg)

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Returns a specification to start this module under a supervisor.

See Supervisor.

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place_child(name, child_spec, opts)

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See FLAME.place_child/3 for more information.

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start_link(opts)

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Starts a pool of runners.

Options

  • :name - The name of the pool, for example: MyApp.FFMPegRunner

  • :min - The minimum number of runners to keep in the pool at all times. For "scale to zero" behavior you may pass 0. When starting as a flame child, the :min will be forced to zero to avoid recursively starting backend resources.

  • :max - The maximum number of runners to elastically grow to in the pool.

  • :max_concurrency - The maximum number of concurrent executions per runner before booting new runners or queueing calls. Defaults to 100.

  • :single_use - if true, runners will be terminated after each call completes. Defaults false.

  • :backend - The backend to use. Defaults to the configured :flame, :backend or FLAME.LocalBackend if not configured.

  • :log - The log level to use for verbose logging. Defaults to false.

  • :timeout - The time to allow functions to execute on a remote node. Defaults to 30 seconds. This value is also used as the default FLAME.call/3 timeout for the caller.

  • :boot_timeout - The time to allow for booting and connecting to a remote node. Defaults to 30 seconds.

  • :shutdown_timeout - The time to allow for graceful shutdown on the remote node. Defaults to 30 seconds.

  • :idle_shutdown_after - The amount of time and function check to idle a remote node down after a period of inactivity. Defaults to 30 seconds. A tuple may also be passed to check a specific condition, for example:

    {10_000, fn -> Supervisor.which_children(MySup) == []}

  • :min_idle_shutdown_after - The same behavior of :idle_shutdown_after, but applied to the the :min pool runners. Defaults to :infinity.

  • :on_grow_start - The optional function to be called when the pool starts booting a new runner beyond the configured :min. The function receives a map with the following metadata:

    • :name - The name of the pool
    • :count - The number of runners the pool is attempting to grow to
    • :pid - The pid of the async process that is booting the new runner

  • :on_grow_end - The optional 2-arty function to be called when the pool growth process completes. The 2-arity function receives either :ok or {:exit, reason}, and map with the following metadata:

    • :name - The name of the pool
    • :count - The number of runners the pool is now at
    • :pid - The pid of the async process that attempted to boot the new runner

  • :on_shrink - The optional function to be called when the pool shrinks. The function receives a map with the following metadata:

    • :name - The name of the pool
    • :count - The number of runners the pool is attempting to shrink to