[Obsolete] Patching required for a known issue in one of MONAI Deploy App SDK's dependencies

[MMelQin]

Note this is obsolete after holoscan v2.9.0 was released on 01/26/2025, and the new version of holoscan CLI, now a standalone package, can also be downloaded and installed. See this announcement please.

One of the dependencies, the newly released Holoscan SDK v2,8.0, has a known issue, so a script is shown below to patch the pip installed Holoscan SDK in the virtual environment before the Holoscan v2.9 is released in February 2025.

This known issue is in the holoscan/core/__init__.py where the MultiMessageConditionInfo was missed in the import, hence not visible when applications try to use it. This file is found in the site-packages once monai-deploy-app-sdk is installed, e.g. at <virtual env>/lib/python3.10/site-packages/holoscan/core/__init__.py.

Further more, the MAP built with CLI packager will have this issue as the packager pulls the latest holoscan~=2.0 from pypi,org as a dependency of monai-deploy-app-sdk, and MAP will again see runtime error. It has been further confirmed that both v2.7 and v2.8 of Holoscan SDK have this issue. To work around it, applications need to explicitly add holoscan~=2.6.0 in its requirements.txt file.

Note if in the local environment pip installing Holoscan==2.6.0 after installing monai-deploy-app-sdk~=2.0, please patch the Holoscan CLI packager Dockerfile template, in the /holoscan/cli/packager/templates/Dockerfile.jinja2, to use a wildcard for versions of pip, ENV PYTHON_PIP_VERSION=22.0.2+dfsg-* . This same change was only made in Holoscan SDK v2.8 and onwards.

It is a simple fix to patch holoscan v2.7 and v2.8 in local env, which can be done manually or by using the following script.

# Copyright 2021 MONAI Consortium
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#     http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

def patch_holoscan():
    """ Patch Holoscan for its known issue of missing one import."""

    import importlib.util
    from pathlib import Path
    spec = importlib.util.find_spec("holoscan")
    if spec:
        # Currently v2.8.1 had one missing import in its __init__.py
        module_to_add = "        MultiMessageConditionInfo,"
        module_path = Path(str(spec.origin)).parent.joinpath('core/__init__.py')
        print(f"Patching file {module_path}")
        if module_path.exists():
            lines_r = []
            existed = False
            with module_path.open("r") as f_to_patch:
                in_block = False
                for line_r in f_to_patch.readlines():
                    if "from ._core import (\n" in line_r:
                        in_block = True
                    elif in_block and module_to_add.strip() in line_r:
                        existed = True
                        break
                    elif in_block and ")\n" in line_r: # not found
                            line_r = f"{module_to_add}\n{line_r}"
                            in_block = False

                    lines_r.append(line_r)

            if not existed:
                with module_path.open("w") as f_w:
                    print(lines_r)
                    f_w.writelines(lines_r)

if __name__ == "__main__":
    patch_holoscan()