dockerfile copy list of files, when list is taken from a local file

Not possible in the sense that the COPY directive allows it out of the box, however if you know the extensions you can use a wildcard for the path such as COPY folder*something*name somewhere/.

For simple requirements.txt fetching that could be:

# but you need to distinguish it somehow# otherwise it'll overwrite the files and keep the last one# e.g. rename package/requirements.txt to package-requirements.txt# and it won't be an issueCOPY */requirements.txt ./RUN for item in $(ls requirement*);do pip install -r $item;done

But if it gets a bit more complex (as in collecting only specific files, by some custom pattern etc), then, no. However for that case simply use templating either by a simple F-string, format() function or switch to Jinja, create a Dockerfile.tmpl (or whatever you'd want to name a temporary file), then collect the paths, insert into the templated Dockerfile and once ready dump to a file and execute afterwards with docker build.

Example:

# Dockerfile.tmplFROM alpine{{replace}}

# organize files into coherent structures so you don't have too many COPY directivesfiles = {    "pattern1": [...],    "pattern2": [...],    ...}with open("Dockerfile.tmpl", "r") as file:    text = file.read()insert = "\n".join([    f"COPY {' '.join(values)} destination/{key}/"    for key, values in files.items()])with open("Dockerfile", "w") as file:    file.write(text.replace("{{replace}}", insert))

You might want to do this for example:

FROM ...ARG filesCOPY files

and run with

docker build -build-args items=`${cat list_of_files_to_copy.txt}`