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* python: rename qemu.aqmp to qemu.qmpJohn Snow2022-04-211-1048/+0
| | | | | | | | | | | | | | | | | | | | | Now that we are fully switched over to the new QMP library, move it back over the old namespace. This is being done primarily so that we may upload this package simply as "qemu.qmp" without introducing confusion over whether or not "aqmp" is a new protocol or not. The trade-off is increased confusion inside the QEMU developer tree. Sorry! Note: the 'private' member "_aqmp" in legacy.py also changes to "_qmp"; not out of necessity, but just to remove any traces of the "aqmp" name. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Beraldo Leal <bleal@redhat.com> Acked-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org> Message-id: 20220330172812.3427355-8-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: drop _bind_hack()John Snow2022-03-071-38/+3
| | | | | | | | | | | | | | | | | _bind_hack() was a quick fix to allow async QMP to call bind(2) prior to calling listen(2) and accept(2). This wasn't sufficient to fully address the race condition present in synchronous clients. With the race condition in legacy.py fixed (see the previous commit), there are no longer any users of _bind_hack(). Drop it. Fixes: b0b662bb2b3 Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-11-jsnow@redhat.com [Expanded commit message. --js] Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add start_server() and accept() methodsJohn Snow2022-03-071-5/+62
| | | | | | | | | | | | | | | | | | | | | Add start_server() and accept() methods that can be used instead of start_server_and_accept() to allow more fine-grained control over the incoming connection process. (Eagle-eyed reviewers will surely notice that it's a bit weird that "CONNECTING" is a state that's shared between both the start_server() and connect() states. That's absolutely true, and it's very true that checking on the presence of _accepted as an indicator of state is a hack. That's also very certainly true. But ... this keeps client code an awful lot simpler, as it doesn't have to care exactly *how* the connection is being made, just that it *is*. Is it worth disrupting that simplicity in order to provide a better state guard on `accept()`? Hm.) Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-9-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: stop the server during disconnect()John Snow2022-03-071-1/+5
| | | | | | | | | | | | Before we allow the full separation of starting the server and accepting new connections, make sure that the disconnect cleans up the server and its new state, too. Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-8-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: refactor _do_accept() into two distinct stepsJohn Snow2022-03-071-5/+24
| | | | | | | | | | | | | | | | Refactor _do_accept() into _do_start_server() and _do_accept(). As of this commit, the former calls the latter, but in subsequent commits they'll be split apart. (So please forgive the misnomer for _do_start_server(); it will live up to its name shortly, and the docstring will be updated then too. I'm just cutting down on some churn.) Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-7-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: squelch pylint warning for too many linesJohn Snow2022-03-071-0/+3
| | | | | | | | | | | I would really like to keep this under 1000 lines, I promise. Doesn't look like it's gonna happen. Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-6-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: split _client_connected_cb() out as _incoming()John Snow2022-03-071-25/+58
| | | | | | | | | | | | | As part of disentangling the monolithic nature of _do_accept(), split out the incoming callback to prepare for factoring out the "wait for a peer" step. Namely, this means using an event signal we can wait on from outside of this method. Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-5-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: remove _new_session and _establish_connectionJohn Snow2022-03-071-72/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | These two methods attempted to entirely envelop the logic of establishing a connection to a peer start to finish. However, we need to break apart the incoming connection step into more granular steps. We will no longer be able to reasonably constrain the logic inside of these helper functions. So, remove them - with _session_guard(), they no longer serve a real purpose. Although the public API doesn't change, the internal API does. Now that there are no intermediary methods between e.g. connect() and _do_connect(), there's no hook where the runstate is set. As a result, the test suite changes a little to cope with the new semantics of _do_accept() and _do_connect(). Lastly, take some pieces of the now-deleted docstrings and move them up to the public interface level. They were a little more detailed, and it won't hurt to keep them. Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-4-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: rename 'accept()' to 'start_server_and_accept()'John Snow2022-03-071-2/+4
| | | | | | | | | | | | | | | | | | | Previously, I had a method named "accept()" that under-the-hood calls bind(2), listen(2) *and* accept(2). I meant this as a simplification and counterpart to the one-shot "connect()" method. This is confusing to readers who expect accept() to mean *just* accept(2). Since I need to split apart the "accept()" method into multiple methods anyway (one of which strongly resembling accept(2)), it feels pertinent to rename this method *now*. Rename this all-in-one method "start_server_and_accept()" instead. Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-3-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add _session_guard()John Snow2022-03-071-27/+62
| | | | | | | | | | | | | | | | | | | | | In _new_session, there's a fairly complex except clause that's used to give semantic errors to callers of accept() and connect(). We need to create a new two-step replacement for accept(), so factoring out this piece of logic will be useful. Bolster the comments and docstring here to try and demystify what's going on in this fairly delicate piece of Python magic. (If we were using Python 3.7+, this would be an @asynccontextmanager. We don't have that very nice piece of magic, however, so this must take an Awaitable to manage the Exception contexts properly. We pay the price for platform compatibility.) Signed-off-by: John Snow <jsnow@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20220225205948.3693480-2-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add socket bind step to legacy.pyJohn Snow2022-02-021-3/+38
| | | | | | | | | | | | | | | | | | | | | | | | The synchronous QMP library would bind to the server address during __init__(). The new library delays this to the accept() call, because binding occurs inside of the call to start_[unix_]server(), which is an async method -- so it cannot happen during __init__ anymore. Python 3.7+ adds the ability to create the server (and thus the bind() call) and begin the active listening in separate steps, but we don't have that functionality in 3.6, our current minimum. Therefore ... Add a temporary workaround that allows the synchronous version of the client to bind the socket in advance, guaranteeing that there will be a UNIX socket in the filesystem ready for the QEMU client to connect to without a race condition. (Yes, it's a bit ugly. Fixing it more nicely will have to wait until our minimum Python version is 3.7+.) Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-id: 20220201041134.1237016-5-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: rename AQMPError to QMPErrorJohn Snow2022-01-211-4/+4
| | | | | | | | | This is in preparation for renaming qemu.aqmp to qemu.qmp. I should have done this from this from the very beginning, but it's a convenient time to make sure this churn is taken care of. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
* python/aqmp: copy type definitions from qmpJohn Snow2022-01-211-6/+10
| | | | | | | | | | Copy the remaining type definitions from QMP into the qemu.aqmp.legacy module. Now, users that require the legacy interface don't need to import anything else but qemu.aqmp.legacy wrapper. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Beraldo Leal <bleal@redhat.com>
* Python/aqmp: fix type definitions for mypy 0.920John Snow2022-01-101-2/+3
| | | | | | | | | | | | | | | | 0.920 (Released 2021-12-15) is not entirely happy with the way that I was defining _FutureT: qemu/aqmp/protocol.py:601: error: Item "object" of the upper bound "Optional[Future[Any]]" of type variable "_FutureT" has no attribute "done" Update it with something a little mechanically simpler that works better across a wider array of mypy versions. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20220110191349.1841027-3-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: fix ConnectError string methodJohn Snow2021-11-161-1/+5
| | | | | | | | | | | | | | | | | | | | When ConnectError is used to wrap an Exception that was initialized without an error message, we are treated to a traceback with a rubbish line like this: ... ConnectError: Failed to establish session: Correct this to use the name of an exception as a fallback message: ... ConnectError: Failed to establish session: EOFError Better! Signed-off-by: John Snow <jsnow@redhat.com> Reported-by: Thomas Huth <thuth@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Message-id: 20211111143719.2162525-3-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: Fix disconnect during capabilities negotiationJohn Snow2021-11-161-5/+13
| | | | | | | | | | | | | | | | | | | | | | | If we receive ConnectionResetError (ECONNRESET) while attempting to perform capabilities negotiation -- prior to the establishment of the async reader/writer tasks -- the disconnect function is not aware that we are in an error pathway. As a result, when attempting to close the StreamWriter, we'll see the same ConnectionResetError that caused us to initiate a disconnect in the first place, which will cause the disconnect task itself to fail, which emits a CRITICAL logging event. I still don't know if there's a smarter way to check to see if an exception received at this point is "the same" exception as the one that caused the initial disconnect, but for now the problem can be avoided by improving the error pathway detection in the exit path. Reported-by: Thomas Huth <thuth@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Message-id: 20211111143719.2162525-2-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: Reduce severity of EOFError-caused loop terminationsJohn Snow2021-10-121-2/+5
| | | | | | | | | | | | | | When we encounter an EOFError, we don't know if it's an "error" in the perspective of the user of the library yet. Therefore, we should not log it as an error. Reduce the severity of this logging message to "INFO" to indicate that it's something that we expect to occur during the normal operation of the library. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210923004938.3999963-7-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add AsyncProtocol._readline() methodJohn Snow2021-09-271-0/+29
| | | | | | | | | | | | | | This is added as a courtesy: many protocols are line-based, including QMP. Putting it in AsyncProtocol lets us keep the QMP class implementation just a pinch more abstract. (And, if we decide to add a QTEST implementation later, it will need this, too. (Yes, I have a QTEST implementation.)) Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-13-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add _cb_inbound and _cb_outbound logging hooksJohn Snow2021-09-271-4/+46
| | | | | | | | | | | | | | | Add hooks designed to log/filter incoming/outgoing messages. The primary intent for these is to be able to support iotests which may want to log messages with specific filters for reproducible output. Another use is for plugging into Urwid frameworks; all messages in/out can be automatically added to a rendering list for the purposes of a qmp-shell like tool. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-12-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add configurable read buffer limitJohn Snow2021-09-271-2/+16
| | | | | | | | | | | QMP can transmit some pretty big messages, and the default limit of 64KB isn't sufficient. Make sure that we can configure it. Reported-by: G S Niteesh Babu <niteesh.gs@gmail.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-11-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add AsyncProtocol.accept() methodJohn Snow2021-09-271-4/+85
| | | | | | | | | | It's a little messier than connect, because it wasn't designed to accept *precisely one* connection. Such is life. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-10-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add logging to AsyncProtocolJohn Snow2021-09-271-9/+73
| | | | | | | | | | Give the connection and the reader/writer tasks nicknames, and add logging statements throughout. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-9-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add runstate state machine to AsyncProtocolJohn Snow2021-09-271-4/+155
| | | | | | | | | | | | | | This serves a few purposes: 1. Protect interfaces when it's not safe to call them (via @require) 2. Add an interface by which an async client can determine if the state has changed, for the purposes of connection management. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-7-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
* python/aqmp: add generic async message-based protocol supportJohn Snow2021-09-271-0/+521
This is the bare minimum that you need to establish a full-duplex async message-based protocol with Python's asyncio. The features to be added in forthcoming commits are: - Runstate tracking - Logging - Support for incoming connections via accept() - _cb_outbound, _cb_inbound message hooks - _readline() method Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-6-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>