Allows for waiting on another actor (by name) to register with the
arbiter. This makes synchronized actor spawning and consecutive task
coordination easier to accomplish from within sub-actors.
Resolves#31
As per a suggestion from @njsmith I've added a little less verbose intro
which mentions *actors* up front.
More,
- add install cmd
- reorg spawning and portal sections a wee bit
This allows for registering more then one actor with the same "name"
when you have multiple actors fulfilling the same role. Eventually
we'll need support for looking up all actors registered under a given
"service name" (or whatever we decide to call it).
Also, a fix to the arbiter such that each new instance refers to a
separate `_registry` dict (found an issue with duplicate names during
testing).
Resolves#7
Start a forkserver once in the main (parent-most) process
and pass ipc info (fds) to subprocesses manually such that embedded
calls to `multiprocessing.Process.start()` just work. Note that this
relies on our overridden version of the stdlib's
`multiprocessing.forkserver` module.
Resolves#6
The stdlib insists on creating multiple forkservers and semaphore trackers
for each sub-sub-process launched. This isn't ideal since it costs each
`tractor` sub-actor an additional 2 more processes then necessary and is
confusing when viewed as a process tree (eg. via `pstree`).
The majority of the change is simply avoiding the call to
`forkserver.ensure_running()` and `semaphore_tracker.ensure_running()`
in `ForkServer.connect_new_process()` and instead treating the user like
an adult and expecting those calls to be made *once* in the parent most
process (i.e. what `multiprocessing` calls the `MainProcess`).
Really a proper patch should be made against cpython which allows for
similar manual management of the server along with a mechanism to communicate
forkserver and semaphore tracker fd info to sub-processes such that
further calls to `Process.start()` work as expected.
Relates to #6
Stop worrying about a "main task" in each actor and instead add an
additional `ActorNursery.run_in_actor()` method which wraps calls
to create an actor and run a lone RPC task inside it. Note this
adjusts the public API of `ActorNursery.start_actor()` to drop
its `main` kwarg.
The dirty deats of making this possible:
- each spawned RPC task is now tracked with a specific cancel scope such
that when the actor is cancelled all ongoing responders are cancelled
before any IPC/channel machinery is closed (turns out that spawning
new actors from `outlive_main=True` actors was probably borked before
finally getting this working).
- make each initial RPC response be a packet which describes the
`functype` (eg. `{'functype': 'asyncfunction'}`) allowing for async
calls/submissions by client actors (this was required to make
`run_in_actor()` work - `Portal._submit()` is the new async method).
- hooray we can stop faking "main task" results for daemon actors
- add better handling/raising of internal errors caught in the bowels of
the `Actor` itself.
- drop the rpc spawning nursery; just use the `Actor._root_nursery`
- only wait on `_no_more_peers` if there are existing peer channels that
are actually still connected.
- an `ActorNursery.__aexit__()` now implicitly waits on `Portal.result()` on close
for each `run_in_actor()` spawned actor.
- handle cancelling partial started actors which haven't yet connected
back to the parent
Resolves#24
Take @njsmith's advice and properly close actor invoked async generators
using `async_generator.aclosing()` instead of hacking it (as previous)
with a shielded cancel scope.
Cancellation requires that each actor cancel it's spawned subactors
before cancelling its own root (nursery's) cancel scope to avoid breaking
channel connections before kill commands (`Actor.cancel()`) have been sent
off to peers. To solve this, ensure each main task is cancelled to
completion first (which will guarantee that all actor nurseries have
completed their cancellation steps) before cancelling the actor's "core"
tasks under the "root" scope.
Tyler Goodlet
goodboy