appImage-builder V1.0.3

Question

I am trying to use the latest version of the appImage-builder because appimages of my application built with the old version of appImage-builder do not run on ubuntu 22.04 anymore. So I got the order to try and see if it works with the new appImage-builder.

Currently (June 2022), only versions below 1.0 which are based on ubuntu 18.04 are available on docker (which we previously used to build our appimage).

The newer versions are available via github (https://github.com/AppImageCrafters/appimage-builder/releases). However, I seem to be unable to execute:

appimage-builder --generate

or

appimage-builder --recipe AppImageBuilder.yml 

Is there any documentation available on how to correctly use the .appimage version of appImage-builder? All I could find in https://appimage-builder.readthedocs.io/en/latest/ seems to refer to the docker version or a manually built version of appImage-builder.

Answer 1

Depending on the error message you get, there could be a couple of issues at play here.

If you got an error related to FUSE, then you need to install the libfuse2 package with apt install libfuse2. AppImages rely on libfuse2, but Ubuntu has stopped including it since 22.04, in favor of libfuse3.

If you get an error related to "file not found", then it could be that you do not have AppImageLauncher installed. Sadly, with type 2 AppImages the design decision was taken to modify the ELF header of the executable with 3 magic bytes at offset 8 of the executable. This means that Linux linkers will not run the file. AppImageLauncher actually copies the file to a temporary directory and zeroes out the magic number in order to be able to execute it.

A good starting point for debugging issues like this is to run the strace command, which will let you see which system call likely cause the error. Keep in mind that if you try to execute a file and you get File not found, it might mean that the linker specified by the file can not be found on the system or the ELF header is not valid. You can also run the executable by using the linker directly, which might give you more clues. For example with: /lib64/ld-linux-x86-64.so.2 <NAME-OF-YOUR-EXECUTABLE>.