Check file existence only after running exec-pre

[Harvie]

Lets say i want to generate some custom/proprietary/niche kind of image that is not supported in genimage and the upstream support does not even make sense. I've found following works quite well. Please note i am demonstrating creation of ext4 image, which is obviously supported by genimage, but lets pretend it's not.

image file.img {
  file {}
  size = 5M
  name = "MYLABEL"
  exec-pre = "truncate -s $IMAGESIZE $IMAGEOUTFILE; mkfs.ext4 -L $IMAGENAME $IMAGEOUTFILE"
}

There is only one problem. exec-pre is not executed unless file.img already exists, so i need to do touch file.img before running genimage. I think it would be nice to have way of postponing the stat() after exec-pre OR providing something like exec-gen that would be executed beforehand.

What do you think about such change?

[michaelolbrich]

I think we should make it explicit instead and have a custom type:

image file.img {
  custom {
      exec = "truncate -s $IMAGESIZE $IMAGEOUTFILE; mkfs.ext4 -L $IMAGENAME $IMAGEOUTFILE"
  }
  size = 5M
  name = "MYLABEL"
}