Since it seems we're building out more and more higher level primitives
in order to support certain parallel style actor trees and messaging
patterns (eg. task broadcast channels), we might as well start a new
sub-package for purely `trio` constructions. We hereby dub this
the realm of `trionics` (like electronics but for trios instead of
electrons).
To kick things off, add an `async_enter_all()` concurrent
exit-stack-like context manager API which will concurrently spawn
a sequence of provided async context managers and deliver their ordered
results but with proper support for `trio` cancellation semantics.
The stdlib's `AsyncExitStack` is not compatible with nurseries not
`trio` tasks (which are cancelled) since as task will be suspended on
the stack after push and does not ever hit a checkpoint until the stack
is closed.
Now that we're on our way to a (somewhat) serious beta release I think
it's about time to start de-noising the logging emissions. Since we're
trying out this approach of "stack layer oriented" log levels, I figured
this is a good time to move most of the "warnings" to what they should
be: cancellation monitoring status messages. The level is set to 16
which is just above our "runtime" level but just below the traditional
"info" level. I think this will be a decent approach since usually if
you're confused about why your `tractor` app is behaving unlike you
expect, it's 90% of the time going to be to do with cancellation or
error propagation. This this setup a user can specify the 'cancel' level
and see all the msgs pertaining to both actor and task-in-actor
cancellation mechanics.
The stdlib's `logging.LoggingAdapter` doesn't currently pass through
`stacklevel: int` down to its wrapped logger instance. Hack it here
and get our msgs looking like they would if using a built-in level.
In an effort to have some kind of more formal interface around the
transport layer, add a `MsgTransport` protocol type and use with
the channel composition of message streams. Start a little "key map"
of `(<codec>, <protocol>)` to `MsgTransport` types which can be
dynamically loaded. Add a `Channel.from_stream()` constructor thus
cleaning up the mangled logic that was in the constructor based on
inputs. Drop all the "auto reconnect" channel logic for now since
nothing is using it (internally) and it's likely it will need rework
once we bring in a protocol besides TCP.
`msgspec` sends python lists over the wire
(https://github.com/jcrist/msgspec/issues/30) which is fine and dandy
but we use them as lookup keys so we need to be sure we tuple-cast
first.
This change some super old (and bad) code from the project's very early
days. For some redic reason i must have thought masking `trio`'s
internal stream / transport errors and a TCP EOF as `StopAsyncIteration`
somehow a good idea. The reality is you probably
want to know the difference between an unexpected transport error
and a simple EOF lol. This begins to resolve that by adding our own
special `TransportClosed` error to signal the "graceful" termination of
a channel's underlying transport. Oh, and this builds on the `msgspec`
integration which helped shed light on the core issues here B)
Add a `tractor._ipc.MsgspecStream` type which can be swapped in for
`msgspec` serialization transparently. A small msg-length-prefix framing
is implemented as part of the type and we use
`tricycle.BufferedReceieveStream` to handle buffering logic for the
underlying transport.
Notes:
- had to force cast a few more list -> tuple spots due to no native
`tuple`decode-by-default in `msgspec`: https://github.com/jcrist/msgspec/issues/30
- the framing can be understood by this protobuf walkthrough:
https://eli.thegreenplace.net/2011/08/02/length-prefix-framing-for-protocol-buffers
- `tricycle` becomes a new dependency
Can only really use an encoder currently since there is no streaming api
in `msgspec` as of currently. See jcrist/msgspec#27.
Not sure if any encoding speedups are currently noticeable especially
without any validation going on yet XD.
First experiments toward #196
- drop `shield` input to `MsgStream`
- check for cancel called prior to loading the feeder mem chan
in `Context.open_stream()`
- warn on a timeout when trying to cancel a remote task from
`Context.cancel()`
- drop noop endofchannel handler block
Follow up to previous commit: extend our simple context test set to
include cancellation via kbi in the parent as well as timeout logic and
testing of the parent opening a stream even though the target actor does
not.
Thanks again to https://github.com/adder46/wrath for discovering this
bug.
Not sure we even have a test for this yet. The main issue discovered by
a user project (https://github.com/adder46/wrath) was that a kbi raised
inside a block like this (with both recv-only and send-recv streams)
would not cancel on the first ctrl-c sent from console and instead
SIGiNT had to be repeatedly sent as many times as there are subactors in
the first level tree. This test catches that as well as just verifies
the basic side-by-side functionality.
Tyler Goodlet
goodboy