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2021-10-12python/aqmp: Disable logging messages by defaultJohn Snow1-0/+4
AQMP is a library, and ideally it should not print error diagnostics unless a user opts into seeing them. By default, Python will print all WARNING, ERROR or CRITICAL messages to screen if no logging configuration has been created by a client application. In AQMP's case, ERROR logging statements are used to report additional detail about runtime failures that will also eventually be reported to the client library via an Exception, so these messages should not be rendered by default. (Why bother to have them at all, then? In async contexts, there may be multiple Exceptions and we are only able to report one of them back to the client application. It is not reasonably easy to predict ahead of time if one or more of these Exceptions will be squelched. Therefore, it's useful to log intermediate failures to help make sense of the ultimate, resulting failure.) Add a NullHandler that will suppress these messages until a client application opts into logging via logging.basicConfig or similar. Note that upon calling basicConfig(), this handler will *not* suppress these messages from being displayed by the client's configuration. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210923004938.3999963-8-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-10-12python/aqmp: Reduce severity of EOFError-caused loop terminationsJohn Snow1-2/+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>
2021-10-12python/aqmp: Add dict conversion method to Greeting objectJohn Snow1-0/+13
The iotests interface expects to return the greeting as a dict; AQMP offers it as a rich object. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210923004938.3999963-6-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-10-12python/aqmp: add send_fd_scmJohn Snow1-0/+22
Add an implementation for send_fd_scm to the async QMP implementation. Like socket_scm_helper mentions, a non-empty payload is required for QEMU to process the ancillary data. A space is most useful because it does not disturb the parsing of subsequent JSON objects. A note on "voiding the warranty": Python 3.11 removes support for calling sendmsg directly from a transport's socket. There is no other interface for doing this, our use case is, I suspect, "quite unique". As far as I can tell, this is safe to do -- send_fd_scm is a synchronous function and we can be guaranteed that the async coroutines will *not* be running when it is invoked. In testing, it works correctly. I investigated quite thoroughly the possibility of creating my own asyncio Transport (The class that ultimately manages the raw socket object) so that I could manage the socket myself, but this is so wildly invasive and unportable I scrapped the idea. It would involve a lot of copy-pasting of various python utilities and classes just to re-create the same infrastructure, and for extremely little benefit. Nah. Just boldly void the warranty instead, while I try to follow up on https://bugs.python.org/issue43232 Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210923004938.3999963-5-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-10-12python/aqmp: Return cleared events from EventListener.clear()John Snow1-2/+7
This serves two purposes: (1) It is now possible to discern whether or not clear() removed any event(s) from the queue with absolute certainty, and (2) It is now very easy to get a List of all pending events in one chunk, which is useful for the sync bridge. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20210923004938.3999963-4-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-10-12python/aqmp: add .empty() method to EventListenerJohn Snow1-0/+6
Synchronous clients may want to know if they're about to block waiting for an event or not. A method such as this is necessary to implement a compatible interface for the old QEMUMonitorProtocol using the new async internals. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20210923004938.3999963-3-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-10-12python/aqmp: add greeting property to QMPClientJohn Snow1-0/+5
Expose the greeting as a read-only property of QMPClient so it can be retrieved at-will. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20210923004938.3999963-2-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp-tui: Add syntax highlightingG S Niteesh Babu1-2/+34
Add syntax highlighting for the incoming and outgoing QMP messages. This is achieved using the pygments module which was added in a previous commit. The current implementation is a really simple one which doesn't allow for any configuration. In future this has to be improved to allow for easier theme config using an external config of some sort. Signed-off-by: G S Niteesh Babu <niteesh.gs@gmail.com> Message-Id: <20210823220746.28295-6-niteesh.gs@gmail.com> Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp-tui: Add AQMP TUIG S Niteesh Babu1-0/+620
Added AQMP TUI. Implements the follwing basic features: 1) Command transmission/reception. 2) Shows events asynchronously. 3) Shows server status in the bottom status bar. 4) Automatic retries on disconnects and error conditions. Also added type annotations and necessary pylint/mypy configurations. Signed-off-by: G S Niteesh Babu <niteesh.gs@gmail.com> Message-Id: <20210823220746.28295-3-niteesh.gs@gmail.com> Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add scary messageJohn Snow1-0/+14
Add a warning whenever AQMP is used to steer people gently away from using it for the time-being. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-24-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add asyncio_run compatibility wrapperJohn Snow1-0/+19
As a convenience. It isn't used by the library itself, but it is used by the test suite. It will also come in handy for users of the library still on Python 3.6. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-23-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add _raw() execution interfaceJohn Snow1-0/+51
This is added in anticipation of wanting it for a synchronous wrapper for the iotest interface. Normally, execute() and execute_msg() both raise QMP errors in the form of Python exceptions. Many iotests expect the entire reply as-is. To reduce churn there, add a private execution interface that will ease transition churn. However, I do not wish to encourage its use, so it will remain a private interface. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-22-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add execute() interfacesJohn Snow2-8/+198
Add execute() and execute_msg(). _execute() is split into _issue() and _reply() halves so that hypothetical subclasses of QMP that want to support different execution paradigms can do so. I anticipate a synchronous interface may have need of separating the send/reply phases. However, I do not wish to expose that interface here and want to actively discourage it, so they remain private interfaces. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-21-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: Add message routing to QMP protocolJohn Snow1-2/+120
Add the ability to handle and route messages in qmp_protocol.py. The interface for actually sending anything still isn't added until next commit. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-20-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add QMP protocol supportJohn Snow2-0/+266
The star of our show! Add most of the QMP protocol, sans support for actually executing commands. No problem, that happens in the next several commits. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-18-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add QMP event supportJohn Snow2-0/+708
This class was designed as a "mix-in" primarily so that the feature could be given its own treatment in its own python module. It gets quite a bit too long otherwise. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-16-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add well-known QMP object modelsJohn Snow1-0/+133
The QMP spec doesn't define very many objects that are iron-clad in their format, but there are a few. This module makes it trivial to validate them without relying on an external third-party library. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-15-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add QMP Message formatJohn Snow2-1/+212
The Message class is here primarily to serve as a solid type to use for mypy static typing for unambiguous annotation and documentation. We can also stuff JSON serialization and deserialization into this class itself so it can be re-used even outside this infrastructure. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-14-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add AsyncProtocol._readline() methodJohn Snow1-0/+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>
2021-09-27python/aqmp: add _cb_inbound and _cb_outbound logging hooksJohn Snow1-4/+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>
2021-09-27python/aqmp: add configurable read buffer limitJohn Snow1-2/+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>
2021-09-27python/aqmp: add AsyncProtocol.accept() methodJohn Snow1-4/+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>
2021-09-27python/aqmp: add logging to AsyncProtocolJohn Snow1-9/+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>
2021-09-27python/aqmp: Add logging utility helpersJohn Snow1-0/+56
Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-8-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add runstate state machine to AsyncProtocolJohn Snow2-5/+160
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>
2021-09-27python/aqmp: add generic async message-based protocol supportJohn Snow3-1/+577
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>
2021-09-27python/aqmp: add asyncio compatibility wrappersJohn Snow1-0/+89
Python 3.6 does not have all of the goodies that Python 3.7 does, and we need to support both. Add some compatibility wrappers needed for this purpose. (Note: Python 3.6 is EOL December 2021.) Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20210915162955.333025-5-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add error classesJohn Snow2-0/+54
Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-3-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2021-09-27python/aqmp: add asynchronous QMP (AQMP) subpackageJohn Snow2-0/+27
For now, it's empty! Soon, it won't be. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-2-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>