Can I install a .deb during a BitBake Build? - deb

Question

Problem Definition
I'm attempting to adapt these rosjava installation instructions so that I can include rosjava on a target image built by the BitBake build system. I'm using the jethro branch of Poky.
Implementation Attempt: Build From .deb with package_deb.bbclass
According to the installation instructions, all that really needs to be done to install rosjava is the following:
sudo apt-get install ros-indigo-rosjava
Which works perfectly fine on my build machine. I figured that if I can just point to a .deb and use the Poky metadata class package_deb, it would do all the heavy lifting for me, so I produced the following simple recipe adapted on this posting on the Yocto Project mailing list:
inherit package_deb
SRC_URI = "http://packages.ros.org/ros/ubuntu/pool/main/r/ros-indigo-rosjava/ros-indigo-rosjava_0.2.1-0trusty-20160207-031808-0800_amd64.deb"
SRC_URI[md5sum] = "2020ccc8b4a67dd918a9a2c426eece0b"
SRC_URI[sha256sum] = "ab9493fabe1285b0d21aab031348d0d733d116b0b2470bae90025709b303b649"
The relevant part of the errors I get during the above recipe's do_unpack are:
| no entry data.tar.gz in archive
|
| gzip: stdin: unexpected end of file
| tar: This does not look like a tar archive
| tar: Exiting with failure status due to previous errors
| DEBUG: Python function base_do_unpack finished
| DEBUG: Python function do_unpack finished
The following command produces the output below:
$ ar t python-rosdistro_0.4.5-1_all.deb
debian-binary
control.tar.gz
data.tar.xz
You can see here that there's a data.tar.xz, not data.tar.gz. What can I do to remedy this error and install from this particular .deb?
I've included package_deb in my PACKAGE_CLASSES variable and package-management in my IMAGE_FEATURES. I've tried other methods of installation which have all failed; I thought this method in particular would be very useful to know how to implement.
Update - 3/22
I'm attempting to circumvent the problems with the method above by doing my installation through a ROOTFS_POSTPROCESS_COMMAND which I've adapted from forum posts like this
install_rosjava() {
${STAGING_BINDIR_NATIVE}/dpkg \
--root=${IMAGE_ROOTFS}/ \
--admindir=${IMAGE_ROOTFS}/var/lib/dpkg/ \
-L /var/cache/apt/archives/ros-indigo-rosjava_0.2.1-0trusty-20160207-031808-0800_amd64.deb
}
ROOTFS_POSTPROCESS_COMMAND += " install_rosjava() ; "
However, this fails due to dpkg not being a command found within the ${STAGING_BINDIR_NATIVE} path. The Yocto Project Reference Manual states that:
STAGING_BINDIR_NATIVE Specifies the path to the /usr/bin subdirectory of the sysroot directory for the build host.
Taking a look inside this directory yields a lot of commands but not dpkg (The recipe depends on the dpkg package, and this command can be found in my target rootfs after the build is finished; I've also tried pointing to ${IMAGE_ROOTFS}/usr/bin/dpkg which yields the same results). From what I understand of the BitBake process, this command may be in another sysroot, but I must admit that this is where my understanding breaks down.
Can I adjust this method so that it works, or will I need to start from scratch on an installation from source?
Perhaps there's a different method entirely which I could consider?

Answer 1

If you really want to install their deb directly then your rootfs postprocess is one solution. It doesn't work because depending on dpkg will build you a dpkg for the target but you want a dpkg that will run on the host. Add a dependency on dpkg-native to your image.
Though personally I'd either inherit bin_package and extract the deb they provide then re-package it as a standard package in OE, or ideally write a proper recipe to build rosjava and submit it to meta-ros (https://github.com/bmwcarit/meta-ros).

Answer 2

package_deb is where the packaging machinery for deb packages is stored, it's not something you'd inherit in a recipe but should be listed in PACKAGE_CLASSES.
When you put a .deb in a SRC_URI the fetcher will try to unpack it so you can access the contents: the assumption is that you're going to repack the contents as a native Yocto recipe.
If that's what you want to do then first you'll need to fix the unpack logic (in bitbake/lib/bb/fetch2/__init__.py) to handle .debs with xz-compressed data. This is a bug in bitbake and a bug report and/or patch would be appreciated.
The alternative would be to use their deb directly but I don't recommend that as it's likely the dependencies don't match. The best long-term solution would be to build it from source directly instead of attempting to use a package for another distro.