[yocto] can all of the licensing discussion be centralized in an appendix?

[Rifenbark, Scott M]

Rudi,

Thanks for taking the time to look this stuff over.  I will place customizing images ahead of adding packages in the dev manual.

I will dig into the other issues and see what I can get in the way of information from the development team.

Scott

From: rstreif at linuxfoundation.org [mailto:rstreif at linuxfoundation.org] On Behalf Of Rudolf Streif
Sent: Thursday, March 29, 2012 1:05 PM
To: Rifenbark, Scott M
Cc: yocto at yoctoproject.org
Subject: Re: [yocto] can all of the licensing discussion be centralized in an appendix?

Scott,

That's great. The dev manual is very comprehensive and at the right level of detail. I think many new as well as more experienced users of YP will appreciate it. From a quick read the only suggestion I have for now is to place the section on "Customizing Images" before the section on "Adding Packages". Most users will probably first build custom images by adding packages using readily available recipes before writing recipes for their own packages.

The reference sections in the reference manual are great. The other sections need more work on coherence. Layers should be added, also a section that deals with the syntax and semantics of setting variables e.g. +=, .= vs. _append etc. This is where most people get confused.

Another thing worth explaining in the reference manual is the use of the Bitbake data structures in Python functions in recipes. This is where I can see folks pulling their hair out too.

I will keep on rummaging through.

Rudi



On Mon, Mar 26, 2012 at 3:28 PM, Rifenbark, Scott M <scott.m.rifenbark at intel.com<mailto:scott.m.rifenbark at intel.com>> wrote:
Rudi,

Great comments!  Thanks very much.  I will immediately update the revision history tables to show the 1.2 release as WIP.  Not having it there did cause you confusion.  Good suggestion.

Regarding your other observations.  If you have the time I would appreciate you looking at the YP Development manual, particularly Chapter 4.  Much of the "how-to" stuff that was in the YP reference manual has been moved to there.  "Adding a Package" section that you noted was now missing is in fact in that area.  Let me give you some background on the strategy of the two manuals....

I am trying to eventually turn the YP reference guide into a "reference" guide with minimal "how-to" information.  That is the long-term goal.  The YP Development Manual has been getting some how-to stuff added to it.  Chapter 4 (Common Tasks) tells how to create layers, add a package, customize images, etc.).

Here is the link to the "latest" YP Development Manual:  http://www.yoctoproject.org/docs/latest/dev-manual/dev-manual.html.  With this new context, maybe you can augment or comment on your previous comments :)

I appreciate your help,
Scott

From: rstreif at linuxfoundation.org<mailto:rstreif at linuxfoundation.org> [mailto:rstreif at linuxfoundation.org<mailto:rstreif at linuxfoundation.org>] On Behalf Of Rudolf Streif
Sent: Monday, March 26, 2012 4:02 PM
To: Rifenbark, Scott M
Cc: yocto at yoctoproject.org<mailto:yocto at yoctoproject.org>

Subject: Re: [yocto] can all of the licensing discussion be centralized in an appendix?

Scott,


>> http://www.yoctoproject.org/docs/latest/poky-ref-manual/poky-ref-manual.html.

Yes, I looked at that one but I now noticed that I referenced it incorrectly. This is the latest version, however, in the revision history it shows "Revision 1.1, October 6, 2011, Released with the Yocto Project Release 1.1".

Now, this one http://www.yoctoproject.org/docs/current/poky-ref-manual/poky-ref-manual.html is the current one but its revision history shows "Revision 1.1.1, March 15, 2012, Released with the Yocto Project Release 1.1.1".

Ok, now I get how I confused myself successfully. I presume that the first is the newer one although its revision history suggests otherwise? Would you mind updating the revision history with something like "Revision 1.2, WIP, To be released with Yocto Project Release 1.2"?

The latest one does not seem to have a section about writing recipes anymore at all. Are you planning on putting it back? While the previous one had a section on writing recipes it did so in a "vacuum". It told you how to write a recipe but not really where to put it and how to include it with an image. The latter it explained in the next section about customizing an image.

The info about the licensing is great and dead-nuts on, however, a reader new to the Yocto Project would be missing the context. A good add-on to that paragraph would be that if you omit the md5 parameter in the LIC_FILES_CHKSUM variable Bitbake will actually spit it out for you which is in particular useful if the checksum is calculated over a subset of a license file specified by startline and endline because md5sum won't easily do that for you.


These are my suggestions:

* Remove 3.3 x32 and 3.4 Licenses from section 3. Section 3 currently looks a little bit like a kitchen sink. The first two paragraphs deal with build system components and architecture, x32 then mixes a very specific technology into it for particular targets, and then Licenses tops it off with package licensing details. I would dedicate Section 3 to Yocto Project Build System Architecture only.

* Then I would dedicate a section 4 to Build Customization:
** The first subsection could deal with the most trivial customization through local.conf: EXTRA_IMAGE_FEATURES, IMAGE_INSTALL_append and CORE_IMAGE_EXTRA_INSTALL (formerly known as POKY_EXTRA_INSTALL)
** The second subsection should then explain how to create your own layer within the build environment because before adding any recipe you need to have a layer to add it to. Mixing your own recipes in with meta or meta-yocto works but is not sustainable when upgrading to a newer release of the Yocto Project. And it's good practice too to keep your own stuff separate.
** The third subsection should then explain how to extend images writing your own recipes:
*** writing a recipe that includes a base image and then adds more packages:
    require recipes-core/images/core-imabg-base.bb<http://core-imabg-base.bb>
    IMAGE_INSTALL += "strace"
*** writing an image that inherits from core-image
    IMAGE_INSTALL = "task-core-boot task-core-extended"
    IMAGE_FEATURES += "blabla"
    inherit core-image
** the fourth subsection should then explain how to add your own packages with your own recipes. Now you already have everything in place: a layer to add to and a ways of including your recipes with an image. And here we then also need to explain the licensing stuff because recipes for building packages won't fly without.
** the fifth section should then just reference the BSP manual for BSPs.

Finally for my concept, we need to find a home for x32. I would put that under an "Advanced Topics" section which could act as a container for other stuff too such as multi-lib etc.

Rudi


From: yocto-bounces at yoctoproject.org<mailto:yocto-bounces at yoctoproject.org> [mailto:yocto-bounces at yoctoproject.org<mailto:yocto-bounces at yoctoproject.org>] On Behalf Of Rudolf Streif
Sent: Monday, March 26, 2012 2:52 PM
To: yocto at yoctoproject.org<mailto:yocto at yoctoproject.org>
Subject: Re: [yocto] can all of the licensing discussion be centralized in an appendix?

>> there's *way* too much coverage of licensing sprinkled throughout.
>> most people are not going to care about licensing until the time comes
>> to maybe start distributing their BSP.
The ability of collecting licensing information, tracking license changes and providing the license information automatically with the images and packages for deployment is in my opinion a major feature of Yocto albeit underestimated. Most people will only appreciate it once they have to deliver that information with a product for the end user. However, it starts much earlier, with the recipe.

How to include licensing tracking information with your recipe needs to be part of the section explaining how to write recipes of the reference manual. In both, the current 1.1 and the upcoming 1.1.1, versions of the manual the license tracking section is a little disjoint from the sections explaining how to add packages/recipes in my opinion. The examples include the license tracking info, of course because otherwise the sanity checker will not allow building the recipe, but they don't explain that you actually need it (unless you use LICENSE = "CLOSED").

Since the license tracking and deployment feature follows the rule "garbage in, garbage out" the manual cannot stress enough providing the correct info in particular when writing recipes for upstream projects.

Side note: And nice features for a future release are SPDX info (already worked on as far as I know) and providing the license info in ${TMPDIR}/deploy/licenses according to the images in ${TMPDIR}/images so that one knows what licenses are in use for what image. That would be very convenient when building multiple images with different package content.

Rudi


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