====== devtool ======

''devtool'' is a helper program for adding and modifying recipes in yocto.
It is available as part of the yocto build environment either through setting up a full yocto build environment, see [[ setup | Setup and Building ]] or through the [[ sdks#extensible_sdk | Extensible SDK]].

Invoking ''devtool'' creates a workspace layer inside the ''build'' directory to store new recipes and modifications to existing ones.
The workspace also includes the sources for all recipes touched by ''devtool'', so that they can easily be modified and persist through cleaning actions such as ''bitbake -c cleanall''. When using a [[sdks#extensible_sdk|Extensible SDK]] the workspace is directly created within it.

Furthermore, ''devtool'' allows for easy creation of patches, at least when used with sources from a ''git'' repository.

===== Commands =====

==== devtool add ====
You can add your own sources and automatically create recipes as given in [[https://docs.yoctoproject.org/sdk-manual/extensible.html#use-devtool-add-to-add-an-application|Add an Application]]. 
<code text>
devtool add <recipe> <srctree>
</code>

==== devtool modify ====
Use the ''devtool modify'' command to begin modifying the source of an existing recipe. The devtool modify command extracts the source for a recipe, sets it up as a Git repository if the source had not already been fetched from Git, checks out a branch for development, and applies any patches from the recipe as commits on top. The repository can now be modified in ''/build/workspace/sources''. Use the command and supply a name of a recipe you want to adapt:

<code text>
devtool modify <recipe>
</code>

==== devtool reset ====
Use the ''devtool reset'' command to remove a recipe and its configuration (e.g. the corresponding .bbappend file) from the workspace layer. From now on the image is build with the default repository linked in the recipe. Specify the recipe you want to reset:

<code text>
devtool reset <recipe>
</code>

==== devtool menuconfig ====
Use the ''devtool menuconfig'' command to change the kernel configuration. 
<code text>
devtool menuconfig <kernel-recipe>
</code>

==== devtool  finish ====
Allow to complete the development done through devtool by updating layer(s) with the work done. Pushes any committed changes to the specified recipe to the specified layer and removes it from your workspace.
<code text>
devtool finish <recipe> <layer/path>
</code>

==== devtool build-image ====
Use the ''devtool build-image'' command to build an image, extending it to include packages from recipes in the workspace. When you use the command, you must supply the name of the image:

<code text>
devtool build-image <image>
</code>
The output tells in which directory the new image was created.

==== devtool build ====
If the change affects only one or a few recipes, you can build this recipes individually with:

<code text>
devtool build <recipe>

# for example:
devtool build ethercattest 
</code>

==== devtool deploy-target ====
The recipe changes described above can be deployed directly to the target machine using the following command:

<code text>
devtool deploy-target <recipe> <target>

# for example:
devtool deploy-target ethercattest root@146.136.37.133
</code>

===== Use Cases =====
  - Modify the device tree of the kernel and put the changes into its own layer <code text>
# build image for [[software:linux:yocto:bblue|Beaglebone Blue]]
# alter device tree in build/workspace/sources/linux-stable-rcn-ee/arch/arm/boot/dts
# commit changes
$ bitbake-layers create-layer ../meta-bsc-os
$ bitbake-layers add-layer ../meta-bsc-os
$ devtool finish -f linux-stable-rcn-ee ../meta-bsc-os/
</code> This creates layer with suitable recipe and adds the new layer to the local //bblayers.conf// file.
  - Repository of used library has new commit. How can you force yocto to fetch the new commit and rebuild the image? Simply, change the source reference in the recipe, e.g. <code text>
#SRCREV = "master"
SRCREV = "bcaf4bfb775b207d5e1e7b8340235050832345f4"
</code>