bitbake recipe - doing a simple copy of the image - yocto

Question

I am attempting to write a recipe that would simple copy two files (MyfileA , MyfileB) to a specific directory when the overall image is built. This is what my directory structure looks like:
MyDir/MyRecipe.bb
MyDir/files/MyfileA
MyDir/files/MyfileB
I would like the two files to be copied to a folder in home (which would not exist initially hence the directories should be created)The folder lets say is called "Testfolder"
This is what my bitbake file looks like
DESCRIPTION = "Testing Bitbake file"
PR = "r0"
SRC_URI = "file://MyfileA \
file://MyfileB "
do_install() {
install -d MyfileA ~/TestFolder/
}
Kindly let me know if I am doing something wrong here?
When i run bitbake on this I get the following
The BBPATH variable is not set and bitbake did not find a conf/bblayers.conf file in the expected location.
Maybe you accidentally invoked bitbake from the wrong directory?
DEBUG: Removed the following variables from the environment: LANG, LS_COLORS, LESSCLOSE, XDG_RUNTIME_DIR, SHLVL, SSH_TTY, OLDPWD, LESSOPEN, SSH_CLIENT, MAIL, SSH_CONNECTION, XDG_SESSION_ID, _, BUILDDIR
Any help in this regard would be appreciated.

Answer 1

First of all, to create your own meta-layer, you should run command yocto-layer create MyRecipe in your Yocto Environment. This is to make sure that you have all the necessary element in your meta layer. Make sure to put the new meta-layer into conf/bblayers.conf
Creating HelloWorld Recipe Video can be found here
Second, to copy a file from one to another directories.
DESCRIPTION = "Testing Bitbake file"
SECTION = "TESTING"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
PR = "r0"
SRC_URI = "file://MyfileA \
file://MyfileB "
#specify where to get the files
S = "${WORKDIR}"
inherit allarch
#create the folder in target machine
#${D} is the directory of the target machine
#move the file from working directory to the target machine
do_install() {
install -d ${D}/TestFolder
install -m ${WORKDIR}/MyfileA ${D}/TestFolder
}
To get more in details, this is my understanding of how the files move around in Yocto.
You have a directory that stored metadata in /sourced/meta-mylayer/recipes-myRecipe/. In that directory, there would be a folder with the same name as the recipe. I.E. myRecipe/ myRecipe_001.bb.
You would store the files that are related to myRecipe.bb (usually it is a patch) in myRecipe/ so that SRC_URI will get into that myRecipe/ directory to grab files. I.E. myFileA, myFileB
Then, you specify the S. This is the location in the Build Directory where unpacked recipe source code resides. By that mean, myFileA and myFileB are moved/copied to there when myRecipe builds.
Usually, S is equal to ${WORKDIR}, this is equivalent to ${TMPDIR}/work/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}
The actual directory depends on several things:
TMPDIR: The top-level build output directory
MULTIMACH_TARGET_SYS: The target system identifier
PN: The recipe name
EXTENDPE: The epoch - (if PE is not specified, which is usually the case for most recipes, then EXTENDPE is blank)
PV: The recipe version
PR: The recipe revision
After that, we inherit allarch. This class is used for architecture independent recipes/data files (usually scripts).
Then, the last thing we have to do is copy the files.
${D} is the location in the Build Directory where components are installed by do_install task. This location defaults to ${WORKDIR}/image
${WORKDIR}/image can also be described as the / directory in the target system.
Go to ${D} directory and create a folder call TestFolder
Then, copy myFileA from ${WORKDIR} to the ${D}/TestFolder
P.S. Please add comment to fix. There might be mistaken information here, cause I learned all this by myself.