Is there a way to easily propagate the output path of a

pex_binary

target to the

extra_build_args

field of a

docker_image

target?

To avoid an x-y problem: Why do you want it in

extra_build_args

? To answer your question, unless you customise

output_directory

, we have a macro that does something like:

target = pex_binary(name="...", ...)

output_directory = ".".join(build_file_dir().parts)
pex_path = f"{output_diretory}/{target.name}.pex"

and I imagine

pex_path

could be fed into

extra_build_args

.

I have a base docker image and I want to generate an image for each pex, but the instructions in the dockerfile are the same, only the pex is different

Ah okay. We do something similar via a macro'd

docker_image

with inline `instructions`: https://pantsbuild.slack.com/archives/C046T6T9U/p1668559231617069?thread_ts=1668559186.539269&cid=C046T6T9U That is, rather than have a fixed

Dockerfile

and pass args in, we just format the instructions appropriately. If that's not appropriate, I'm guessing adapting the

docker_image

to have something like

extra_build_args=[f"PACKAGED_PEX={pex_path}"], dependencies=[":{target.name}"]

would work (I think you'll need the explicit dependency on the PEX in that case, because I assume pants won't infer from

extra_build_args

, but it will infer if the appropriate string appears in the instructions)