`tox` is a standard testing tool for Python projects, this allows you to
test locally with all your installed Python version with the following
command:
`tox -m test -p all`
To run the tests in parallel for all supported Python versions.
To run linters or type analysis:
```
tox -m lint -p all
tox -m type -p all
```
This commit *also* disables the `import-error` warning from `pylint`,
not all Python versions have the system-installed Python libraries
available and they can't be fetched from PyPI.
Some linters have been added and the general order linters run in has
been changed. This allows for quicker test failure when running
`tox -m lint`. As a consequence the `test_pylint` test has been removed
as it's role can now be fulfilled by `tox`.
Other assorted linter fixes due to newer versions:
- use a str.join method (`consider-using-join`)
- fix various (newer) mypy and pylint issues
- comments starting with `#` and no space due to `autopep8`
This also changes our CI to use the new `tox` setup and on top of that
pins the versions of linters used. This might move into separate
requirements.txt files later on to allow for easier updating of those
dependencies.
Add support for emitting signals to host.Service which can be used to
transmit data back to the client during an ongoing method call. This
provides the possibility for the services to send information to their
client counterpart while running. The signal can take file descriptors
as extra parameters to send data on separate files.
If there are fds to send back to the client, do a check that none
of them are invalid, so that we do not raise an exception in send
later. This allows us to send a proper RemoteError instead of no
reply at all.
When decoding a message, first check that it is not empty and
raise a `ProtocolError` otherwise. This prevent a more obscure
error like "NoneType has no get method".
On the service server side, i.e. the actual host service binary,
when we receive a message that contains file descriptors, clean
then up eagerly, instead relying on the garbage collector.
More importantly, the fds that we get from as a reply, if any,
need to be closed since in the current model the ownership is
transferred to the caller of `dispatch`.
Catch the BrokenPipeError exception when sending a reply. This will
happen when the other side closes their side of the connection/pipe
so in that case we just break out of the serve loop.
Host services are a way to provide functionality to stages that is
restricted to the host and not directly available in the container,
such as providing input to stages, devices access and mounting.
This commit introduces a `ServiceManager` class that can be used to
start and (automatically) stop host service, as well as a `Service`
base class together with a `ServiceClient` class that be used to
implement host services and communicate with them. Refer to the doc
string of the module for more information.
