[OE-core] Lock external repository in custom FSTYPE

[Stefan Agner]

On 29.10.2018 14:01, Khem Raj wrote:
> On Mon, Oct 29, 2018 at 5:31 AM Stefan Agner <stefan at agner.ch> wrote:
>>
>> Hi,
>>
>> We use meta-updater, which has a custom FSTYPE to build a OSTree
>> repository. We share that repository across multiple bitbake executions.
>> The underlying OSTree tools lock the OSTree repository before trying to
>> interact, and if it fails ("error: Locking repo exclusive failed:
>> Resource temporarily unavailable") then the complete build fails (see
>> also https://github.com/advancedtelematic/meta-updater/issues/412).
>>
>> Now I'd rather prefer that two bitbake tasks would serialize the access
>> to the OSTree repository. Is there a mechanism in bitbake to lock (and
>> wait) for the repository to be not in use?
>>
>> We tried using bb.utils.lockfile, but the task is written in shell. Also
>> inline Python would not work since locking/unlocking need to be done
>> within one Python script as far as I understand.
>>
> 
> perhaps you could use lockfiles something like
> 
> do_foo[lockfiles] = ...

Wasn't aware of the lockfiles varflag, also seems not to appear in any
documentation. Reading lib/bb/build.py suggests that it really is
locking the complete task, exactly what we need.

Added the lockfiles varflag to the do_image_ostree task in
image_types_ostree.bbclass:
do_image_ostree[lockfiles] += "${OSTREE_REPO}/ostree.lock"

And run two builds, the OSTree lock issues seem to be gone. Thanks Khem!

--
Stefan

> 
>> --
>> Stefan
>> --
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