Yocto bitbake .bbappend not installing file - yocto

Question

I am trying to add a json to /etc on a device.
Have read many SO answers and not found a solution.
The new json is called audio_config.json, it is under files/ in the same directory as the .bbappend. Am using append because this file is needed only on one device model while the main recipe is on many models.
Doing this:
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
SRC_URI += "file://audio_config.json"
do_install_append() {
install -d ${D}${sysconfdir}
install -m 644 ${B}/audio_config.json ${D}${sysconfdir}
}
Gets an error saying that the json is not in the work directory.
The same thing happens if I use ${WORKDIR} instead of ${B}.
Other recipes in this tree follow this same model, not sure what the problem is.
If I use ${THISDIR} then it says that the json is not located in the base recipe directory - which it's not supposed to be.
From SO posts I have tried
FILES_${PN}-audio_config.json = "${sysconfdir}/audio_config.json"
But that seems to have no effect.
TIA!

Answer 1

In do_unpack() the file is copied to ${WORKDIR}, not ${B} (build dir) and not ${S} (sources dir). This recipe works for me with Yocto Dunfell:
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
SRC_URI += "file://audio_config.json"
do_install_append() {
install -d ${D}${sysconfdir}
install -m 644 ${WORKDIR}/audio_config.json ${D}${sysconfdir}
}
Note the different source path argument in the second call to install.
I'm guessing that there was a yocto/bitbake bug that affected you.

Answer 2

According to users and documentation, what I had above should have worked. But it didn't.
What did work was this:
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
AUDIO_CONFIG_FILES := "${THISDIR}/files"
do_install_append() {
install -d ${D}${sysconfdir}
install -m 644 ${AUDIO_CONFIG_FILES}/audio_config.json ${D}${sysconfdir}
}
Using a variable for immediate expansion of $THISDIR set the local path correctly and the install occurs.

Answer 3

You were right to add the FILES_${PN} to add the file to the image. But do not add any suffix to it, just append your file to the variable:
FILES_${PN} += "${sysconfdir}/audio_config.json"
Also, you should use the ${WORKDIR} in your install.
install -m 644 ${WORKDIR}/audio_config.json ${D}${sysconfdir}
Also check the work directory of your package to get some logs and see the files actually retrieved for an easier debugging.