[yocto] Two Stage Package Recipe

[Darcy Watkins]

I took a stab at this and found that the only way I could handle this is
to split the package up.

See interspersed with my original email.

The short answer is that I had to split it into three package, each with
its own recipe.

(I may revisit this down the road using classes such as those that are
used for having a single package build for target, build a '-native' for
the build host and in some cases, for the SDK).



-- 

Regards,

Darcy

Darcy Watkins ::  Staff Engineer, Firmware

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On Sat, 2015-01-24 at 08:56 -0800, Darcy Watkins wrote:
> Hello,
> 
> 
> I have a package in my BSP layer, let’s just call it “my-platform”.
> At present, it builds libraries to implement a HW access API along
> with command line utilities useful for testing and diagnostics (and
> using the API from shell scripts).  At present, it also uses the
> host-swig to generate interface libraries for python bindings and java
> bindings to access the HW API.
> 
> 
> This means that ‘my-platform’ has to depend both on ‘python’ and
> on ‘openjdk-7-jre’ to build.
> 

The issue that triggered the need is that openjdk-7-jre has been broken
due to something that changed in QEMU so I want to be able to build the
base package, then a package for the python bindings and then a package
for the java bindings (that I can disable until I have the java build
back up again).

The objective is to have these handled using dependencies based on what
images and/or distro layers call up.

For example, my-image-full build everythings but my-image-nojava
excludes the java components.

> 
> What I would like to do is to have the default build to the recipe to
> build it all EXCEPT for the java bindings.  So I would want to build
> all the usual libraries and utilities and have this NOT have
> dependency on ‘openjdk-7-jre’.
> 

I tried to place these into separate PACKAGEs (i.e. separate RPM
outputs).  That works great, however I was not able to have outside
dependencies select these on individual basis.  The build seems to be
for all or none.  It is like I need to be able to have do_compile,
do_install etc. phases for multiple items inside the package, with each
chain accessible for dependency rules.

> 
> Then without having to treat it as a different package, I would like
> to be able to re-invoke the build to build the java bindings.  This
> particular step will need to be dependent on ‘openjdk-7-jre’ without
> making earlier steps to be dependent on ‘openjdk-7-jre’.
> 

Had to make separate packages:

  my-platform          - for base items
  python-my-platform   - for python bindings to the libraries
  my-platform-java     - for java bindings to the libraries

The one-to-many relationship from source to generated outputs is handled
by all three recipes retrieving common source.

> 
> I envision that this should result in one RPM output with the first
> build products, and the second RPM output with the java bindings
> (addons).
> 

I had hoped that this could be handled using a single recipe based on
one source retrieval and three generated outputs, but it appears I need
to implement it as three recipes.

> 
> In the end, I will want to be able to have a minimalistic image
> include and depend on ‘my-package’ without java bindings, and then
> have a full feature image that includes and depends on the java
> bindings.
> 

Although not as elegant as I hoped, I was able to get this to happen.