hub v0.6.3 Hub.Channel
GenServer that handles a single channel. This serializes publishes, subscribes and unsubscribes on that channel, and makes sure no race condition can occur.
Link to this section Summary
Functions
Returns a specification to start this module under a supervisor.
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
Publishes the message to all matching subscribers of this channel. Returns number of subscribers that the message was sent to.
Starts the Channel
Subscribes with the quoted pattern
Get all subscribers from channel
Unsubscribes using the reference returned on subscribe
Link to this section Types
count()
count() :: pos_integer() | :infinity
count() :: pos_integer() | :infinity
pattern()
pattern() :: any()
pattern() :: any()
subscribe_option()
subscribe_options()
subscribe_options() :: [subscribe_option()]
subscribe_options() :: [subscribe_option()]
subscription_ref()
Link to this section Functions
child_spec(init_arg)
Returns a specification to start this module under a supervisor.
See Supervisor
.
init(channel_name)
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
init_arg
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
.
publish(channel, message)
publish(pid(), any()) :: non_neg_integer()
publish(pid(), any()) :: non_neg_integer()
Publishes the message to all matching subscribers of this channel. Returns number of subscribers that the message was sent to.
start_link(channel_name)
start_link(String.t()) :: GenServer.on_start()
start_link(String.t()) :: GenServer.on_start()
Starts the Channel
subscribe_quoted(channel, quoted_pattern, options \\ [])
subscribe_quoted(pid(), any(), subscribe_options()) ::
{:ok, subscription_ref()} | {:error, reason :: String}
subscribe_quoted(pid(), any(), subscribe_options()) :: {:ok, subscription_ref()} | {:error, reason :: String}
Subscribes with the quoted pattern
subscribers(channel)
subscribers(pid()) :: [Hub.Subscriber.t()]
subscribers(pid()) :: [Hub.Subscriber.t()]
Get all subscribers from channel
unsubscribe(arg)
unsubscribe(subscription_ref()) :: :ok
unsubscribe(subscription_ref()) :: :ok
Unsubscribes using the reference returned on subscribe