[bitbake-devel] python function used in variable expansion called multiple times per recipe

[Daniel Lazzari]

>
>On Thu, Apr 19, 2012 at 4:13 PM, Daniel Lazzari <dlazzari at leapfrog.com>
>wrote:
>>
>>
>>>On Thu, 2012-04-19 at 21:24 +0000, Daniel Lazzari wrote:
>>>> >> I think immediate expansion is what I’ll need to use, thanks for the tip.
>>>> >> That at least brings the invocation down to once per run.
>Unfortunately,
>>>the
>>>> >> variable doesn’t seem to get filled in when I change to immediate
>>>> >expansion.
>>>> >>
>>>> >> def testFunc(bb, d):
>>>> >>                 print( bb.data.getVar("PN", d, True) )
>>>> >>                 return "e1"
>>>> >>
>>>> >> EXTERNPV := "${@testFunc(bb, d)}"
>>>> >>
>>>> >> Now only prints the package name once, but using –e, I don’t see the
>>>> >> variable EXTERNPV at all.
>>>> >
>>>> >Don't know what to tell you. It does work, so it's something wrong on
>>>> >your end. Either it's returning an empty string, which will result in
>>>> >-e only showing the commented out definition, or it's raising an
>>>> >exception, or something else in your setup. Aside: you don't need to
>>>> >pass 'bb' in. That namespace is always accessible, even from def'd
>>>> >python functions.
>>>> >--
>>>> >Christopher Larson
>>>>
>>>> Just thought I'd provide an update real quick on this. I discovered,
>>>> to my dismay, that even doing an immediate expansion still ran the
>>>> code before every task for that recipe. I switched to using an event
>>>> handler, but the RecipeParsed event occurs before every task for that
>>>> recipe. Eventually I discovered that the variable BB_WORKERCONTEXT is
>>>> set for RecipeParsed events when they are occurring before a task, but
>>>> not for the initial parse. Also, I discovered that setting a variable
>>>> in the event handler would not necessarily keep it set through
>>>> building the recipe. Thus I devised the below code to run the time
>>>> intensive code during initial parse and cache the value in a file so
>>>> it can be picked up again in later events. I'm leaving this here in
>>>> case it helps someone else.
>>>
>>>Just as a note, we have the persist_data code in bitbake which was
>>>written for this kind of reason in relation to SRCREV and AUTOINC which
>>>uses a sqlite backend as the storage. There isn't anything wrong with
>>>what you're doing, I just thought I'd mention it.
>>>
>>>Cheers,
>>>
>>>Richard
>>
>> That sounds like a better alternative, but I have no idea how to implement
>it. Is there documentation for it? I'm not even sure how to get at the
>persist_data from the event handler. Is there a way to access it using d or
>something?
>
>The bb.persist_data python module just provides a convenience
>dictionary wrapper around an sqlite3 database.
>
>persist = bb.persist_data.persist('some_identifier', d)
>persist['foo'] = 'bar'
>--
>Christopher Larson

That worked wonderfully! Thanks to both of you for all of your help.