Compute Hash for LXD / Incus Image

Hash for metadata file

metadata = Path.expand("~/Downloads/incus.tar.xz")
hash_ref = :crypto.hash_init(:sha256)

metadata
|> File.stream!([], 2048)
|> Enum.reduce(hash_ref, fn chunk, prev_ref ->
  :crypto.hash_update(prev_ref, chunk)
end)
|> :crypto.hash_final()
|> Base.encode16()
|> String.downcase()

Section

squash = Path.expand("~/Downloads/rootfs.squashfs")
another_ref = :crypto.hash_init(:sha256)

squash
|> File.stream!([], 2048)
|> Enum.reduce(another_ref, fn chunk, prev_ref ->
  :crypto.hash_update(prev_ref, chunk)
end)
|> :crypto.hash_final()
|> Base.encode16()
|> String.downcase()

Combined Hash

metadata = Path.expand("~/Downloads/incus.tar.xz")
rootfs = Path.expand("~/Downloads/rootfs.squashfs")

hash_ref = :crypto.hash_init(:sha256)

[metadata, rootfs]
|> Enum.reduce(hash_ref, fn file, prev_ref ->
  file
  |> File.stream!([], 2048)
  |> Enum.reduce(prev_ref, fn chunk, ref ->
    :crypto.hash_update(ref, chunk)
  end)
end)
|> :crypto.hash_final()
|> Base.encode16()
|> String.downcase()