[Python] Docker-mounted folder appears empty inside Flask backend container causing...

I'm developing a Flask backend running inside a Docker container. My backend needs to process medical DICOM files located on the host machine in a folder like /host/path/runs/container_1/input. I mounted the volume on docker via docker-compose.yml. I work with medical AI-Container which is pure input-output based CLI Container which operates in . It works prefectly when i use docker bash commands to make it do what it is supposed to but when i test the same function via API it doesnt find any Files in input folder. The API code i attached works but is very very hardcoded and i need to make it universal for different devices and different OS like Linux and Windows. Thanks !

@api_blueprint.route("/analyze_dicom/<int:container_id>", methods=["POST"])
def analyze_dicom(container_id):
container = Container.query.get(container_id)
if not container:
return jsonify({"error": "Container not found"}), 404

#Hardcoded host path (real Windows path)
base_host_path = PureWindowsPath(f"C:/mraay/mRayAIR_MEP_2025/container_manager/app/runs")
input_dir = base_host_path / f"container_{container_id}" / "input"
output_dir = base_host_path / f"container_{container_id}" / "output"

try:
result = run([
"docker", "run", "--rm",
"--ipc=host",
"--ulimit", "memlock=-1",
"--ulimit", "stack=67108864",
"-v", f"{input_dir}:/data:ro",
"-v", f"{output_dir}:/output",
container.image,
"bash", "-c",
"echo 'Inside container: /data'; ls -l /data; echo '---'; TotalSegmentator -i /data -o /output --fast --verbose"
],
check=True,
capture_output=True,
text=True)

return jsonify({
"message": f"Analysis successful for container {container_id}",
"input_used": str(input_dir),
"output_created": str(output_dir),
"returncode": result.returncode,
"stdout": result.stdout,
"stderr": result.stderr
}), 200

except CalledProcessError as e:
return jsonify({
"error": "Container execution failed",
"details": str(e),
"stdout": e.stdout,
"stderr": e.stderr
}), 500**

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