Is there any way to copy multiple directories in one command, to reduce the number of layers? E.g., instead of:
COPY dirone ./dirone
COPY dirtwo ./dirtwo
COPY dirthree ./dirthree
I want to do:
COPY dirone/ dirtwo/ dirthree/ ./
However, this copies the contents of the directories... but I want to copy the directories themselves.
That's the documented behavior of the copy command:
If
<src>is a directory, the entire contents of the directory are copied, including filesystem metadata.Note: The directory itself is not copied, just its contents.
Best workaround I can suggest is to change your directory layout in your build folder, move the three folders under one parent folder and add the parent.
As BMitch answered, that is expected COPY behaviour.
An alternative would be to ADD the contents of a tarball.
Create the initial tarball
tar -cvf dirs.tar dirone/ dirtwo/ dirthree/
Add it to the build
FROM busybox
ADD dirs.tar /
CMD find /dirone /dirtwo /dirthree
The tarball is automatically extracted
○ →docker run c28f96eadd58
/dirone
/dirone/one
/dirtwo
/dirtwo/two
/dirthree
/dirthree/three
Note that every time you update the tar file you are invalidating the Docker build cache for that step. If you are dealing with a lot of files you might want to be smart about when you do the tar -c. You could also use tar -u if you can deal with files not being automatically deleted from the tarball.
[ -f dirs.tar ] && tar -uf dirs.tar something || tar -cf dirs.tar something
