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Phoenix.PubSub.Local

PubSub implementation for handling local-node process groups.

This module is used by Phoenix pubsub adapters to handle their local node subscriptions and it is usually not accessed directly. See Phoenix.PubSub.PG2 for an example integration.

Summary

Functions

broadcast(fastlane, pubsub_server, pool_size, from, topic, msg)

Sends a message to all subscribers of a topic

child_spec(arg)

Returns a specification to start this module under a supervisor

init(arg)

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

start_link(server_name, gc_name)

Starts the server

subscribe(pubsub_server, pool_size, pid, topic, opts \\ [])

Subscribes the pid to the topic

subscribers(pubsub_server, topic, shard)

Returns a set of subscribers pids for the given topic

subscribers_with_fastlanes(pubsub_server, topic, shard)

Returns a set of subscribers pids for the given topic with fastlane tuples. See subscribers/1 for more information

unsubscribe(pubsub_server, pool_size, pid, topic)

Unsubscribes the pid from the topic

Functions

broadcast(fastlane, pubsub_server, pool_size, from, topic, msg)

Sends a message to all subscribers of a topic.

  • pubsub_server - The registered server name
  • pool_size - The size of the pool
  • topic - The string topic, for example “users:123”

Examples

iex> broadcast(MyApp.PubSub, 1, self(), "foo")
:ok
iex> broadcast(MyApp.PubSub, 1, :none, "bar")
:ok

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

init(arg)

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(server_name, gc_name)

Starts the server.

  • server_name - The name to register the server under

subscribe(pubsub_server, pool_size, pid, topic, opts \\ [])

Subscribes the pid to the topic.

  • pubsub_server - The registered server name
  • pool_size - The size of the pool
  • pid - The subscriber pid
  • topic - The string topic, for example “users:123”
  • opts - The optional list of options. Supported options only include :link to link the subscriber to local

Examples

iex> subscribe(MyApp.PubSub, 1, self(), "foo")
:ok

subscribers(pubsub_server, topic, shard)

Returns a set of subscribers pids for the given topic.

  • pubsub_server - The registered server name or pid
  • topic - The string topic, for example “users:123”
  • shard - The shard, for example 1

Examples

iex> subscribers(:pubsub_server, "foo", 1)
[#PID<0.48.0>, #PID<0.49.0>]

subscribers_with_fastlanes(pubsub_server, topic, shard)

Returns a set of subscribers pids for the given topic with fastlane tuples. See subscribers/1 for more information.

unsubscribe(pubsub_server, pool_size, pid, topic)

Unsubscribes the pid from the topic.

  • pubsub_server - The registered server name
  • pool_size - The size of the pool
  • pid - The subscriber pid
  • topic - The string topic, for example “users:123”

Examples

iex> unsubscribe(MyApp.PubSub, 1, self(), "foo")
:ok

© 2014 Chris McCord
Licensed under the MIT License.
https://hexdocs.pm/phoenix_pubsub/Phoenix.PubSub.Local.html