Generate a file and deploy it to image, inside a yocto recipe

I need to generate some kind of manifest, based on the contents of the recipe. This file needs to be deployed to the image as well.

To generate a file, I have seen in many bbclasses that python code functions are used in a similar way such as:

      python do_create_manifest () {
          [...]
          filename = d.expand("${D}${LOC}/${MANIFEST_NAME}")
          [...]
          with open (filename,'w') as manifest_file:
             json.dump(manifest_dict, manifest_file, indent=True)
          os.chmod(filename, 0o644)
      }

Is there any other preferred way?

The file is created after adding the task dependency, however when such file is packaged, the host-user-contaminated warning arises in the file.

Despite I have seen in many recipes the use of:

        chown -R root:root ${D}${...}/${...}

This fails, as chown needs to be run by root, and bitbake is ran by current user:

Log data follows:
| DEBUG: Executing shell function do_uncontaminate
| chown: changing ownership of '/mnt/thud/build-r0w/[...]/manifest.json': Operation not permitted
| WARNING: exit code 1 from a shell command.

How would I fix the host-user-contaminated warning in this case?

Note: I know this would prevent the warning from appearing, but not solving the problem.

    INSANE_SKIP_${PN} = "host-user-contaminated"

Solution

You don't specify where this file gets created, what path filename contains, but from the error I suspect you create it directly under ${D} somewhere.

If you instead create the manifest file under e.g. ${B}, and then during the regular do_install you install it using e.g. install -Dm0644 ${B}/my_manifest ${D}/dest/path/my_manifest the ownership issue will be taken care of as with any other file that a recipe installs.

Just make sure that the do_create_manifest task is run before do_install.