Broadway v0.1.0 Broadway.TermStorage View Source
A simple term storage to avoid passing large amounts of data between processes.
If you have a large amount of data and you want to avoid passing it between
processes, you can use the TermStorage
. The TermStorage
creates a unique
reference for it, allowing you pass the reference around instead of the term.
If the same term is put multiple times, it is stored only once, avoiding generating garbage. However, the stored terms are never removed. A common use case for this feature is in Broadway.Producer, which may need to pass a lot of information to acknowledge messages. With this module, you can store those terms when the producer starts and only pass the reference between messages:
iex> ref = Broadway.TermStorage.put({:foo, :bar, :baz}) # On init
iex> Broadway.TermStorage.get!(ref) # On ack
{:foo, :bar, :baz}
Link to this section Summary
Functions
Returns a specification to start this module under a supervisor
Gets a previously stored term
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Puts a term
Link to this section Functions
child_spec(arg) View Source
Returns a specification to start this module under a supervisor.
See Supervisor
.
get!(ref) View Source
Gets a previously stored term.
init(atom) View Source
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 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
.
put(term) View Source
Puts a term.