Using anonymous python function to define variables

Using anonymous python function to define variables

[Ulf Winberg]

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I'm struggling with trying to dynamically set a file name, to be used with
"require". See code below:

python () {
       TA = d.getVar('TARGET_ARCH', True)
       if TA == "arm":
               javaPkg = "oracle-jse-ejre-arm-vfp-hflt-client-headless"
       elif TA == "i586":
               javaPkg = "oracle-jse-jre-i586"
       elif TA == "x86_64":
               javaPkg = "oracle-jse-jre-x86-64"
       else:
               raise Exception("Target architecture '%s' is not supported
by the meta-oracle-java layer" %TA)
       d.setVar('JAVA_PKG', javaPkg)
}

require ${JAVA_PKG}.inc

The python function executes properly (if I print javaPkg, it shows up
correctly) but the "JAVA_PKG" variable does not become available for
"require". From what I can read in section 3.4.4 in this link
<http://www.yoctoproject.org/docs/1.6/bitbake-user-manual/bitbake-user-manual.html>,
it seems to me it should work. Could someone please explain to me why it
doesn't?

Thank you in advance!

Ulf

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Re: Using anonymous python function to define variables

[Paul Eggleton]

Hi Ulf,

On Sunday 07 December 2014 12:22:06 Ulf Winberg wrote:
> I'm struggling with trying to dynamically set a file name, to be used with
> "require". See code below:
> 
> python () {
>        TA = d.getVar('TARGET_ARCH', True)
>        if TA == "arm":
>                javaPkg = "oracle-jse-ejre-arm-vfp-hflt-client-headless"
>        elif TA == "i586":
>                javaPkg = "oracle-jse-jre-i586"
>        elif TA == "x86_64":
>                javaPkg = "oracle-jse-jre-x86-64"
>        else:
>                raise Exception("Target architecture '%s' is not supported
> by the meta-oracle-java layer" %TA)
>        d.setVar('JAVA_PKG', javaPkg)
> }
> 
> require ${JAVA_PKG}.inc
> 
> The python function executes properly (if I print javaPkg, it shows up
> correctly) but the "JAVA_PKG" variable does not become available for
> "require". From what I can read in section 3.4.4 in this link
> <http://www.yoctoproject.org/docs/1.6/bitbake-user-manual/bitbake-user-manua
> l.html>, it seems to me it should work. Could someone please explain to me
> why it doesn't?

I'm pretty sure this is because anonymous functions don't get executed until 
finalize() is called, which is towards the end of parsing; the "require" 
statement must be handled immediately. Try this instead:

---------------- snip ----------------

def get_java_package(d):
    TA = d.getVar('TARGET_ARCH', True)
    if TA == "arm":
        javaPkg = "oracle-jse-ejre-arm-vfp-hflt-client-headless"
    elif TA == "i586":
        javaPkg = "oracle-jse-jre-i586"
    elif TA == "x86_64":
        javaPkg = "oracle-jse-jre-x86-64"
    else:
        raise bb.parse.SkipPackage("Target architecture '%s' is not supported 
by the meta-oracle-java layer" % TA)
    return javaPkg

JAVA_PKG = "${@get_java_package(d)}"

require ${JAVA_PKG}.inc

---------------- snip ----------------

The question is though, do you really need a separate inc file for each 
architecture? You can use overrides for this sort of thing e.g.:

---------------- snip ----------------

SOMEVAR = "default value"
SOMEVAR_arm = "value if arm"
SOMEVAR_x86-64 = "value if x86-64"

---------------- snip ----------------

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre

Re: Using anonymous python function to define variables

[Ulf Winberg]

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Thanks! Using python as a function with return value solved it.

When bb.parse.SkipPackage is used, there seems to be no warning when
building. Does the text I wrote end up in a log somewhere?

I was testing the SOMEVAR example you give. Am I right to assume that the
overrides only works for gobal variables, already defined elsewhere? I was
not able to define one myself and use the overrides.

Cheers,
Ulf

On Mon, Dec 8, 2014 at 10:41 AM, Paul Eggleton <
paul.eggleton@linux.intel.com> wrote:
>
> Hi Ulf,
>
> On Sunday 07 December 2014 12:22:06 Ulf Winberg wrote:
> > I'm struggling with trying to dynamically set a file name, to be used
> with
> > "require". See code below:
> >
> > python () {
> >        TA = d.getVar('TARGET_ARCH', True)
> >        if TA == "arm":
> >                javaPkg = "oracle-jse-ejre-arm-vfp-hflt-client-headless"
> >        elif TA == "i586":
> >                javaPkg = "oracle-jse-jre-i586"
> >        elif TA == "x86_64":
> >                javaPkg = "oracle-jse-jre-x86-64"
> >        else:
> >                raise Exception("Target architecture '%s' is not supported
> > by the meta-oracle-java layer" %TA)
> >        d.setVar('JAVA_PKG', javaPkg)
> > }
> >
> > require ${JAVA_PKG}.inc
> >
> > The python function executes properly (if I print javaPkg, it shows up
> > correctly) but the "JAVA_PKG" variable does not become available for
> > "require". From what I can read in section 3.4.4 in this link
> > <
> http://www.yoctoproject.org/docs/1.6/bitbake-user-manual/bitbake-user-manua
> > l.html>, it seems to me it should work. Could someone please explain to
> me
> > why it doesn't?
>
> I'm pretty sure this is because anonymous functions don't get executed
> until
> finalize() is called, which is towards the end of parsing; the "require"
> statement must be handled immediately. Try this instead:
>
> ---------------- snip ----------------
>
> def get_java_package(d):
>     TA = d.getVar('TARGET_ARCH', True)
>     if TA == "arm":
>         javaPkg = "oracle-jse-ejre-arm-vfp-hflt-client-headless"
>     elif TA == "i586":
>         javaPkg = "oracle-jse-jre-i586"
>     elif TA == "x86_64":
>         javaPkg = "oracle-jse-jre-x86-64"
>     else:
>         raise bb.parse.SkipPackage("Target architecture '%s' is not
> supported
> by the meta-oracle-java layer" % TA)
>     return javaPkg
>
> JAVA_PKG = "${@get_java_package(d)}"
>
> require ${JAVA_PKG}.inc
>
> ---------------- snip ----------------
>
> The question is though, do you really need a separate inc file for each
> architecture? You can use overrides for this sort of thing e.g.:
>
> ---------------- snip ----------------
>
> SOMEVAR = "default value"
> SOMEVAR_arm = "value if arm"
> SOMEVAR_x86-64 = "value if x86-64"
>
> ---------------- snip ----------------
>
> Cheers,
> Paul
>
> --
>
> Paul Eggleton
> Intel Open Source Technology Centre
>

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Re: Using anonymous python function to define variables

[Paul Eggleton]

On Friday 12 December 2014 16:19:39 Ulf Winberg wrote:
> Thanks! Using python as a function with return value solved it.

Great!
 
> When bb.parse.SkipPackage is used, there seems to be no warning when
> building. Does the text I wrote end up in a log somewhere?

SkipPackage (or SkipRecipe which should really now be used instead) just marks 
the recipe as skipped - you only see the message when you try to build that 
recipe.

> I was testing the SOMEVAR example you give. Am I right to assume that the
> overrides only works for gobal variables, already defined elsewhere? I was
> not able to define one myself and use the overrides.

No, that should work for any variable (and you can see existing examples where 
we do that, e.g. 
meta/recipes-core/packagegroups/packagegroup-core-tools-profile.bb )

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre