qemu.qmp 0.0.0a0

QEMU Monitor Protocol library.

This package provides an asyncio library used for communicating with QEMU Monitor Protocol (“QMP”) servers. It requires Python 3.6+ and has no other dependencies.

This library can be used for communicating with QEMU emulators or with the QEMU Guest Agent (QGA), QEMU Storage Daemon (QSD) or any other utility or application that speaks QMP.

This library makes as little assumptions as possible about the actual version or what type of endpoint it will be communicating with; i.e. this library does not contain command definitions and does not seek to be an SDK or a replacement for tools like libvirt/virsh. It is “simply” the protocol (QMP) and not the vocabulary (QAPI). It is up to the programmer (you!) to know which commands and arguments you want to send.

Who is this library for?

It is firstly for developers of QEMU themselves; as the test infrastructure of QEMU itself needs a convenient and scriptable interface for testing QEMU. This library was split out of the QEMU source tree in order to share a reference version of a QMP library that was usable both within and outside of the QEMU source tree.

Second, it’s for those who are developing for QEMU by adding new architectures, devices, or functionality; as well as targeting those who are developing with QEMU, i.e. developers working on integrating QEMU features into other projects such as libvirt, kubevirt, kata containers, etc. Occasionally, using existing VM management stacks that integrate QEMU+kvm can make developing, testing, and debugging features difficult and more ‘raw’ access is required. This library is for you.

Lastly, it’s for power users who already use QEMU directly without the aid of libvirt because they require the raw control and power this affords them.

Who is this library NOT for?

It is not designed for anyone looking for a turn-key solution for VM management. QEMU is a low-level component that resembles a swiss army knife with 5,000 attachments. This library does not manage that complexity at all and is largely “QEMU ignorant”, and so it is not a replacement for projects like libvirt, virtual machine manager, boxes, etc.

Installing

This package can be installed with pip using pip3 install qemu.qmp.

Usage

At its simplest, script-style usage looks like this:

from qemu.qmp import QMPClient

qmp = QMPClient('my-vm-nickname')
await qmp.connect('/path/to/qmp.sockfile')

res = await qmp.execute('query-status')
print(f"VM status: {res['status']}")

await qmp.disconnect()

The above script will connect to the UNIX socket located at /path/to/qmp.sockfile and query the VM’s runstate and print it out to the terminal.

For more complex usages, especially those that make full advantage of monitoring asynchronous events; refer to the online documentation or type help(qemu.qmp) in your Python terminal of choice.

Contributing

Contributions are quite welcome! Please file bugs using the GitLab issue tracker. This project will accept GitLab merge requests, but due to the close association with the QEMU project, there are some additional guidelines:

1. Please use the “Signed-off-by” tag in your commit messages. See https://wiki.linuxfoundation.org/dco for more information on this requirement.

2. This repository won’t squash merge requests into a single commit on pull; each commit should seek to be self-contained (within reason).

3. Owing to the above, each commit sent as part of a merge request should not introduce any temporary regressions, even if fixed later in the same merge request. This is done to preserve bisectability.

4. Please associate every merge request with at least one GitLab issue. This helps with generating Changelog text and staying organized. Thank you 🙇

Developing

Optional packages necessary for running code quality analysis for this package can be installed with the optional dependency group “devel”: pip install qemu.qmp[devel].

make develop can be used to install this package in editable mode (to the current environment) and bring in testing dependencies in one command.

make check can be used to run the available tests. Consult make help for other targets and tests that make sense for different occasions. (Personally: I run make check-tox && make check-pipenv locally before submitting to GitLab CI as my due diligence.)

Changelog

• No public release yet.