Hi Michael,
See my replies below.
On 11/10/2015 02:27 PM, Michael Habibi wrote:
This is fundamentally why I have been looking into Yocto/BB/OE as a
potential replacement distribution. However, I have a couple questions
stemming from my research. We can leverage the existing Yocto build for
various open source utilities where it pulls from the web, patches, builds,
and installs into the deployable image. We would probably want to colocate
the tarballs locally, because we would like to prevent people from having
to fetch from the web during build cycles.
This is pretty common. You can set up SOURCE_MIRROR_URL, to specify local
mirrors to try before using the upstream url in the recipe. So each person
building would at least have to fetch from the local mirror for a build, but
subsequent builds wouldn't require fetching again as long as the DL_DIR was
preserved.
https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#var-SOURCE_MIRROR_URL
https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#var-DL_DIR
I see that Yocto thinks of the deployable image and applications as
separate entities: first you'd build the distribution, then you would use
ADT/cross-toolchain/etc to build the applications and install them
separately. However, in our environment, we would need all of our custom IP
applications to be built as part of the deployable image, and not as a
separate procdure. For example, if I were to call "bitbake our-image", I
would like the deployable image to contain 1) the kernel, 2) various core
utilities and libraries for booting, and 3) our custom applications for our
device.
This means that somewhere in the yocto framework, we'd ideally have some
source code somewhere that would also be compiled via recipes/classes that
we'd have to custom write. Is there a best practice for this kind of
workflow? I don't mind not having source checked in to our VCS for things
like the kernel, OpenSSL, etc (those can be tarballs obtained from a local
server), but we likely wouldn't want to host tarballs for the applications
we are writing and modifying day-to-day by dozens of engineers. Is there a
place where this source would best fit? Would it be under build/tmp/etc, or
perhaps we can locate the source under a layer directory, like
meta/source/our-ip-applications?
For all the internal applications at my previous employer we had a layer for all
internal items, it's quite common.
And if you're not aware, source code is not restricted to tarballs. You can use
git repos, svn and any mechanism the fetcher supports.(even local directories)
The following URL lists the types the fetcher supports.
https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#var-SRC_URI
The workflow now encouraged, is to use recipetool to assist in creating recipes.
And then once the recipes are created, you can use devtool to actually do the
iterative development on the application represented by the recipe.
https://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#using-devtool-in-your-workflow
Or perhaps this workflow is just not recommended or supported by the Yocto
Project? If that's the case, does Yocto only recommend building the
distribution then building the applications as completely separate
workflows? Or is there another workflow that I haven't stumbled across yet?
There is nothing "wrong" with building the image each time as a developer.
However, it is time consuming to construct the full image and deploy it.
A much more appealing mechanism would be to use devtool to build the recipe you
are working on, and then use "devtool deploy-target" to then deploy the output
to a live machine. This would require a writeable filesystem on the target
device, but if that is available, the workflow and turnaround time is much faster.
Thanks again for all your help, and let me know if I can help clarify
anything,
Michael
--
_______________________________________________
yocto mailing list
yocto@yoctoproject.org
https://lists.yoctoproject.org/listinfo/yocto
