RFC: new 'yocto-layer' tool for creating generic Yocto layers

From: Tom Zanussi <[email protected]>

Since I've been doing kind of similar work lately for the 'custom kernel' support for yocto-bsp and have gotten several requests lately (mainly from Darren in support of the new kernel documentation) for something like this, I decided to just go ahead and try to quickly implement a general-purpose layer-generation tool based on the BSP-generation code used in the yocto-bsp tool.

There's actually an enhancement request bug for this already in the Yocto bugzilla, but it doesn't contain many details:

Bug 3094 - Add a layer generation tool:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=3094

So anyway, this is my initial take on what that bug means. It's an RFC for a couple reasons, first that I'd like to get comments on whether this is actually what's needed for a 'layer generation tool', and second, because I still need to do some cleanup of the refactored code, but don't want to waste much time on it if it's not really what's needed.

Below are a couple examples of how it's used - you really have to try it yourself to see what's generated - I don't want to post tarballs or such on the list and it's simple to generate and look at the layers.

The first case is just a very simple layer with a layer.conf and README - basically the simplest layer you can create, and which exists mainly because even that is easy to get wrong. As with the yocto-bsp tool, the script queries the user for a couple items, here we just take the defaults, which are a priority of 6 for the layer and no other components such as example recipes:

[trz@empanada build]$ yocto-layer create simplestlayer
Please enter the layer priority you'd like to use for the layer: [default: 6] Would you like to have an example recipe created? (y/n) [default: n] Would you like to have an example bbappend file created? (y/n) [default: n]

New layer created in meta-simplestlayer.

Don't forget to add it to your BBLAYERS (for details see meta-simplestlayer\README).

[trz@empanada build]$ find .
.
./meta-simplestlayer
./meta-simplestlayer/conf
./meta-simplestlayer/conf/layer.conf
./meta-simplestlayer/README
./meta-simplestlayer/COPYING.MIT

In the second case, we tell the tool that we do want an example .bb and and an example .bbappend. We're queried for the recipe name that we want our recipe to have, and for the .bbappend, the name of the base recipe and its version. Below you can see the files it generates - please look at the files themselves to see the contents. For the recipe example, it generates a recipe based on the example in the Yocto manual, and my own helloworld.c code (untested so far which is also why this is an RFC). For the .bbappend example, it just creates an empty .patch file with some instructions on what to do to modify the parent recipe with a patch:

[trz@empanada build]$ yocto-layer create mylayer
Please enter the layer priority you'd like to use for the layer: [default: 6]
Would you like to have an example recipe created? (y/n) [default: n] y
Please enter the name you'd like to use for your example recipe: [default: example] flork
Would you like to have an example bbappend file created? (y/n) [default: n] y
Please enter the name you'd like to use for your bbappend file: [default: example] chork
Please enter the version number you'd like to use for your bbappend file (this should match the recipe you're appending to): [default: 0.1] 0.22.3

New layer created in meta-mylayer.

Don't forget to add it to your BBLAYERS (for details see meta-mylayer\README).

[trz@empanada build]$ find .
.
./meta-mylayer
./meta-mylayer/recipes-example
./meta-mylayer/recipes-example/example ./meta-mylayer/recipes-example/example/flork-0.1 ./meta-mylayer/recipes-example/example/flork-0.1/helloworld.c ./meta-mylayer/recipes-example/example/flork-0.1/example.patch ./meta-mylayer/recipes-example/example/flork_0.1.bb ./meta-mylayer/conf
./meta-mylayer/conf/layer.conf
./meta-mylayer/recipes-example-bbappend ./meta-mylayer/recipes-example-bbappend/example-bbappend ./meta-mylayer/recipes-example-bbappend/example-bbappend/chork-0.22.3 ./meta-mylayer/recipes-example-bbappend/example-bbappend/chork-0.22.3/example.patch ./meta-mylayer/recipes-example-bbappend/example-bbappend/chork_0.22.3.bbappend ./meta-mylayer/README
./meta-mylayer/COPYING.MIT

Please try it and look at the generated code - any comments or suggestions are welcome.

Thanks,

Tom

The following changes since commit da598d4f0fcf6faa62055084a51d70d735399d33:

eglibc: fix checksums of fetched patches (2012-12-13 18:02:21 +0000)

are available in the git repository at:

git://git.yoctoproject.org/poky-contrib.git tzanussi/yocto-layer-rfc
http://git.yoctoproject.org/cgit/cgit.cgi/poky-contrib/log/?h=tzanussi/yocto-layer-rfc

Tom Zanussi (5):
scripts/lib/bsp/engine.py: add yocto_layer_create()
yocto-layer: new script
yocto-layer: add help/usage
yocto-layer: add 'layer' template data scripts/lib/bsp/engine.py: refactor bsp-creation code

 scripts/lib/bsp/engine.py                          |  86 +++++++-
 scripts/lib/bsp/help.py                            | 228 +++++++++++++++++++++
 .../bsp/substrate/target/arch/layer/COPYING.MIT    |  17 ++
 scripts/lib/bsp/substrate/target/arch/layer/README |  64 ++++++
 .../substrate/target/arch/layer/conf/layer.conf    |  10 +
 .../target/arch/layer/layer-questions.noinstall    |  14 ++
 .../example.patch"                                 |  12 ++
 ..._name}}_{{=example_bbappend_version}}.bbappend" |   8 +
 .../{{=example_recipe_name}}-0.1/example.patch"    |  12 ++
 .../{{=example_recipe_name}}-0.1/helloworld.c"     |   6 +
 .../example/{{=example_recipe_name}}_0.1.bb"       |  23 +++
 scripts/yocto-layer                                | 142 +++++++++++++
 12 files changed, 612 insertions(+), 10 deletions(-)
 create mode 100644 scripts/lib/bsp/substrate/target/arch/layer/COPYING.MIT
 create mode 100644 scripts/lib/bsp/substrate/target/arch/layer/README
 create mode 100644 scripts/lib/bsp/substrate/target/arch/layer/conf/layer.conf
 create mode 100644 scripts/lib/bsp/substrate/target/arch/layer/layer-questions.noinstall
 create mode 100644 "scripts/lib/bsp/substrate/target/arch/layer/{{ if create_example_bbappend == \"y\": }} recipes-example-bbappend/example-bbappend/{{=example_bbappend_name}}-{{=example_bbappend_version}}/example.patch"
 create mode 100644 "scripts/lib/bsp/substrate/target/arch/layer/{{ if create_example_bbappend == \"y\": }} recipes-example-bbappend/example-bbappend/{{=example_bbappend_name}}_{{=example_bbappend_version}}.bbappend"
 create mode 100644 "scripts/lib/bsp/substrate/target/arch/layer/{{ if create_example_recipe == \"y\": }} recipes-example/example/{{=example_recipe_name}}-0.1/example.patch"
 create mode 100644 "scripts/lib/bsp/substrate/target/arch/layer/{{ if create_example_recipe == \"y\": }} recipes-example/example/{{=example_recipe_name}}-0.1/helloworld.c"
 create mode 100644 "scripts/lib/bsp/substrate/target/arch/layer/{{ if create_example_recipe == \"y\": }} recipes-example/example/{{=example_recipe_name}}_0.1.bb"
 create mode 100755 scripts/yocto-layer

1.7.11.4