[OE-core] How to find out why shared sstate is not being used for a recipe

[Mike Looijmans]

On 06/03/2014 04:10 PM, Richard Purdie wrote:
> On Tue, 2014-06-03 at 15:54 +0200, Mike Looijmans wrote:
>> On 06/03/2014 10:45 AM, Richard Purdie wrote:
>>> the next steps depend upon how clear the differences are. Basically
>>> there should be some degree of commonality between the two builds and at
>>> some point there will be divergence. We need to pinpoint the point of
>>> divergence. The divergence will be in fpga-image-miami itself or in one
>>> of its dependencies.
>>
>> ALL stamps for ALL tasks for fpga-image-miami are different. There's a few
>> thousand lines in these files, with very few similarities.
>
> Ok, this gives a very strong pointer then, see below.
>
>> I'll just go for the "do_fetch" task then, since that's about the first to
>> execute.
>
> This is a good move.
>
>> So far, on one project (that is, NOT the fpga-image-miami) the SRC_URI is
>> slightly different. The machines are on various sides of a router/firewall, so
>> SRC_URI="git://${MY_SERVER}/blabla" evaluates differently.
>>
>> How can I tell the system that the value of "MY_SERVER" is irrelevant to each
>> and every build step in each and every recipe?
>
> The SRC_URI changing would indeed cause the tasks build separately since
> bitbake thinks they're different things.
>
> You have two ways of addressing this. Firstly, you could setup PREMIRROR
> entries for these git urls which remaps them to the correct thing in
> each case. There would then be one "canonical" url in the recipe and
> you'd not need to change the hash generation.
>
> The other way would be to either exclude the variable from the checksum
> generation or give it a specific value. This would be something like:
>
> do_fetch[vardepsexclude] += "SRC_URI"
>
> you may also have to do this with other tasks that use SRC_URI such as
> do_unpack and do_patch. The other option is:
>
> SRC_URI[vardepvalue] = "git://canonical/url/for/recipe"
>
> which gives it a specific value to use for checksum purposes.

In this case, a very useful syntax. The machines have different MY_SERVER 
values in their local.conf, so I've changed one into:

MY_SERVER = "git://some/local/path"
MY_SERVER[vardepvalue] = "git://common.server/path"

This generates the same SRC_URI signatures for the locations that look 
different but actually refer to the same location.

The PREMIRROR sounds like a generic solution to the underlying problem of 
accessing servers from different locations. I'll keep that in mind for the 
next project.

Next, I'll need to investigate why the fpga-image-miami generates different 
signatures, as both machines fetch it from the same URI.

Mike.


Met vriendelijke groet / kind regards,

Mike Looijmans

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