Re: [Qemu-devel] [PATCH v2 1/3] Bootstrap Python venv for tests

[Cleber Rosa <crosa@redhat.com>]

On 10/9/18 12:13 PM, Philippe Mathieu-Daudé wrote:
> On 09/10/2018 18:00, Cleber Rosa wrote:
>>
>>
>> On 10/9/18 9:25 AM, Philippe Mathieu-Daudé wrote:
>>> Hi Cleber,
>>>
>>> On 09/10/2018 06:18, Cleber Rosa wrote:
>>>> A number of QEMU tests are written in Python, and may benefit
>>>> from an untainted Python venv.
>>>>
>>>> By using make rules, tests that depend on specific Python libs
>>>> can set that rule as a requiment, along with rules that require
>>>> the presence or installation of specific libraries.
>>>>
>>>> The tests/venv-requirements.txt is supposed to contain the
>>>> Python requirements that should be added to the venv created
>>>> by check-venv.
>>>>
>>>> Signed-off-by: Cleber Rosa <crosa@redhat.com>
>>>> ---
>>>>  tests/Makefile.include      | 19 +++++++++++++++++++
>>>>  tests/venv-requirements.txt |  3 +++
>>>>  2 files changed, 22 insertions(+)
>>>>  create mode 100644 tests/venv-requirements.txt
>>>>
>>>> diff --git a/tests/Makefile.include b/tests/Makefile.include
>>>> index 7a3059bf6c..68af79927d 100644
>>>> --- a/tests/Makefile.include
>>>> +++ b/tests/Makefile.include
>>>> @@ -12,6 +12,7 @@ check-help:
>>>>  	@echo " $(MAKE) check-block          Run block tests"
>>>>  	@echo " $(MAKE) check-tcg            Run TCG tests"
>>>>  	@echo " $(MAKE) check-report.html    Generates an HTML test report"
>>>> +	@echo " $(MAKE) check-venv           Creates a Python venv for tests"
>>>>  	@echo " $(MAKE) check-clean          Clean the tests"
>>>>  	@echo
>>>>  	@echo "Please note that HTML reports do not regenerate if the unit tests"
>>>> @@ -1015,6 +1016,23 @@ check-decodetree:
>>>>            ./check.sh "$(PYTHON)" "$(SRC_PATH)/scripts/decodetree.py", \
>>>>            TEST, decodetree.py)
>>>>  
>>>> +# Python venv for running tests
>>>> +
>>>> +.PHONY: check-venv
>>>> +
>>>> +TESTS_VENV_DIR=$(BUILD_DIR)/tests/venv
>>>> +TESTS_VENV_REQ=$(SRC_PATH)/tests/venv-requirements.txt
>>>> +
>>>> +$(TESTS_VENV_DIR):
>>>> +	$(call quiet-command, \
>>>> +            $(PYTHON) -m venv --system-site-packages $@, \
>>>
>>> Why do we want the '--system-site-packages' flag?
>>>
>>
>> It allows the reuse of packages (with no additional downloads) in case
>> there's a package installed system wide providing the same package and
>> version.  If you have, say, an RPM or DEB (or even a pip) package
>> installed system wide, it'll be copied over to the venv.  This was based
>> on a suggestion by Eduardo.
> 
> Some system-site-packages are broken (or too old?).
> 

It could be, yes.  I'm starting to believe that this may bring more
problems that it'd solve.

>>
>>>> +            VENV, $@)
>>>> +	$(call quiet-command, \
>>>> +            $(TESTS_VENV_DIR)/bin/pip -q install -r $(TESTS_VENV_REQ), \
>>>
>>> On Ubuntu I have to use (after installing python3-pip + python3.4-venv):
>>>
>>>                $(PYTHON) -m pip -q install -r $(TESTS_VENV_REQ), \
>>>
>>
>> I don't think running $(PYTHON) is the right thing to do here because it
>> points to non-venv Python interpreter.  IMO it should be:
>>
>>                 $(TESTS_VENV_DIR)/bin/python -m pip ...
> 
> Yes it worked: https://travis-ci.org/philmd/qemu/jobs/439216885
> 

Nice! I'll take a picture of that and hang on my wall. :)

Now, there's still one point: which Python version was used there? I'm
guessing it was Python 3.4, and not the Travis "provided" 3.6, right?

- Cleber.

>>
>>>> +            PIP, $(TESTS_VENV_REQ))
>>>> +
>>>> +check-venv: $(TESTS_VENV_DIR)
>>>
>>> Same problem from v1: if check-venv failed and the directory exists, the
>>> rule succeeds.
>>>
>>
>> I really don't know how to make all the steps of this target "atomic",
>> unless I do an ugly "venv ... && touch ... && pip ...".  The best I
>> managed to think was to flag the requirement as fulfilled by touching
>> the venv directory after pip finishes.
>>
>> - Cleber.
>>
>>>> +
>>>>  # Consolidated targets
>>>>  
>>>>  .PHONY: check-qapi-schema check-qtest check-unit check check-clean
>>>> @@ -1028,6 +1046,7 @@ check-clean:
>>>>  	rm -rf $(check-unit-y) tests/*.o $(QEMU_IOTESTS_HELPERS-y)
>>>>  	rm -rf $(sort $(foreach target,$(SYSEMU_TARGET_LIST), $(check-qtest-$(target)-y)) $(check-qtest-generic-y))
>>>>  	rm -f tests/test-qapi-gen-timestamp
>>>> +	rm -rf $(TESTS_VENV_DIR)
>>>>  
>>>>  clean: check-clean
>>>>  
>>>> diff --git a/tests/venv-requirements.txt b/tests/venv-requirements.txt
>>>> new file mode 100644
>>>> index 0000000000..d39f9d1576
>>>> --- /dev/null
>>>> +++ b/tests/venv-requirements.txt
>>>> @@ -0,0 +1,3 @@
>>>> +# Add Python module requirements, one per line, to be installed
>>>> +# in the tests/venv Python virtual environment. For more info,
>>>> +# refer to: https://pip.pypa.io/en/stable/user_guide/#id1
>>>>