David Aldrich wrote:
> Hi
>
> I wonder if someone could help me with this problem please. I am writing
> a Python script that builds and tests a C++ program on Linux. The build
> options depend on the test, so I have encapsulated the 'make' call in a
> Python function:
>
> def build(build_options=''):
> if len(build_options):
> subprocess.check_call(['make',build_options])
> else:
> subprocess.check_call('make')
>
> This works fine if I call:
>
> build()
> or
> build('flagA=true')
>
> The latter gives:
>
> make flagA=true
>
> which is correct.
>
> However, I now want to call make with two flags:
>
> make flagA=true flagB=true
>
> I tried calling:
>
> build('flagA=true flagB=true')
>
> which did indeed result in:
>
> make flagA=true flagB=true
>
> but 'make' ignored the second option. So I think that the list that was
> passed to subprocess.check_call() was incorrect.
That's because you effectively call
subprocess.check_call(["make", "flagA=true flabB=true"])
i. e. you are providing a single parameter "flagA=true flabB=true" instead
of two separate "flagA=true" and "flabB=true"
> In summary, I want to pass a list to build(), which by default should be
> empty, and pass that list on to subprocess.check_call() with 'make' as the
> first element of the list.
>
> Any ideas please?
The straightforward approach is to pass a list or tuple:
def build(build_options=()):
subprocess_check_call(("make",) + build_options)
build(("flagA=true", "flagB=true"))
Allowing separate arguments may be more convenient to use:
def build(*build_options):
subprocess.check_call(("make",) + build_options)
build("flagA=true", "flagB=true")
Or, if the order of flags doesn't matter:
def build(*args, **kw):
subprocess.check_call(("make",) + args +
tuple("{}={}".format(*p) for p in kw.items()))
build(flagA="true", flagB="true")
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