====== NervProj: support for dedicated python env ======

{{tag>dev python nervproj}}

I'm just about to start working on a new large python project, and I would like to use my **NervProj** to handle the project management part. But the proble now is that I still need to be able to run that new project completely independently from NervProj itself.

So this means I should setup a dedicated python environment in this kind of sub project. Let's see here how we should proceed step by step.

====== ======

==== Regular/embedded sub project ====

  * So let's say I'm working on a project called "my_project", and with code name "myp".
  * My current "regular" process is to do the following:
    * Create the project repository on my gitlab server (say in sub path /my_group/my_project)
    * Then add that project in the master **nervproject.config.json** file: <sxh javascript; highlight: []>{
  "projects": [
   {
      "names": ["my_project", "myp"],
      "repository_url": "ssh://git@gitlab.nervtech.org:22002/my_group/my_project.git"
    }
  ]
}</sxh>
    * Then I checkout the project: <sxh bash; highlight: []>$ cd /cygdrive/d/Projects
$ nvp -p myp git clone</sxh>
    * And finally I perform the project init stage: <sxh bash; highlight: []>$ nvp -p myp admin init
2022/04/27 14:03:26 [nvp.components.admin] INFO: No change in C:\Users\kenshin\AppData\Roaming\Code\User\settings.json
2022/04/27 14:03:26 [nvp.components.admin] INFO: Wrtting updated vscode settings in D:\Projects\my_project\.vscode\settings.json
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting python env file D:\Projects\my_project\.vs_env
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting editor config file D:\Projects\my_project\.editorconfig
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting .gitignore file D:\Projects\my_project\.gitignore
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting .gitattributes file D:\Projects\my_project\.gitattributes
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting nvp_config.json file D:\Projects\my_project\nvp_config.json
2022/04/27 14:03:26 [nvp.components.admin] INFO: Writting nvp_plug.py file D:\Projects\my_project\nvp_plug.py
2022/04/27 14:03:26 [nvp.components.admin] INFO: Adding pull section in git config.</sxh>

==== Extending the init command ====

  * => I think it is in the init command above that I should introduce the required updates:
  * I need a flag to disable the deployment of the NVP plugin files (nvp_config.json/nvp_plug.py) ? Or maybe not: that is not really important for now so let's not do it.
  * I need to add a flag to deploy the python packages such as: <sxh bash; highlight: []>$ nvp -p myp admin init --with-py-env</sxh>
  * **Note** also using the short flag version: <sxh bash; highlight: []>$ nvp -p myp admin init -p</sxh>

  * And so I've started to update the init command with some special handling whena python env deployment is requested: <sxh python; highlight: []>        ignore_elems = []

        if with_py:
            # We deploy the python packages:
            dest_dir = self.get_path(proj_dir, "tools", "packages")
            self.make_folder(dest_dir)
            # get the python version on windows:
            py_vers = {}
            sevenzip_vers = {}

            for plat_name in ["windows", "linux"]:
                for el in self.config[f'{plat_name}_tools']:
                    if el["name"] == 'python':
                        py_vers[plat_name] = el["version"]
                    if el["name"] == '7zip':
                        sevenzip_vers[plat_name] = el["version"]

            for plat_name, py_version in py_vers.items():
                for ext in [".7z", ".tar.xz"]:
                    file_name = f"python-{py_version}-{plat_name}{ext}"
                    src_file = self.get_path(self.ctx.get_root_dir(), "tools", "packages", file_name)
                    dst_file = self.get_path(dest_dir, file_name)
                    if self.file_exists(src_file) and not self.file_exists(dst_file):
                        logger.info("Adding package file %s", dst_file)
                        self.copy_file(src_file, dst_file)

            # Next, for the windows part we need to deploy the 7zip package too:
            folder_name = f"7zip-{sevenzip_vers['windows']}"
            src_folder = self.get_path(self.ctx.get_root_dir(), "tools", "windows", folder_name)
            dst_folder = self.get_path(proj_dir, "tools", "windows", folder_name)
            if not self.dir_exists(dst_folder):
                logger.info("Adding windows 7zip package at %s", dst_folder)
                self.copy_folder(src_folder, dst_folder)

            # Update the ignore elements:
            ignore_elems += ["",
                             "# Ignore all the windows tools except the 7zip folder:",
                             "tools/windows/*",
                             "!tools/windows/7zip-*",
                             "tools/linux/*"]

            # Should also install an requirements.txt file:
            dest_file = self.get_path(proj_dir, "tools", "requirements.txt")
            if not self.file_exists(dest_file):
                logger.info("Installing pythong requirements file.")
                content = ["# List here all the required python packages,"
                           "# Then call install_requirements.sh/install_requirements.bat"
                           "pylint",
                           "autopep8",
                           ""]
                content = "\n".join(content)
                self.write_text_file(content, dest_file)</sxh>

  * Next step at this level is to also deploy some shell scripts to allow running the python app => I can use the NervProj cli.sh/cli.bat as a starting point, but I don't need to support building python from sources here.

  * => **OK**, so now in the init command I'm also installing the required scripts as follow: <sxh python; highlight: []>            # Should install the cli script files:
            dest_file = self.get_path(proj_dir, "cli.py")
            if not self.file_exists(dest_file):
                logger.info("Writting cli python file %s", dest_file)
                content = DEFAULT_CLI_PY_CONTENT
                self.write_text_file(content, dest_file)

            dest_file = self.get_path(proj_dir, "cli.sh")
            if not self.file_exists(dest_file):
                logger.info("Writting cli shell file %s", dest_file)
                content = DEFAULT_CLI_SH_CONTENT
                content = content.replace("${PROJ_NAME}", proj_name.lower())
                # Use the linux python version below:
                content = content.replace("${PY_VERSION}", py_vers['linux'])
                self.write_text_file(content, dest_file, newline="\n")

            dest_file = self.get_path(proj_dir, "cli.bat")
            if not self.file_exists(dest_file):
                logger.info("Writting cli batch file %s", dest_file)
                content = DEFAULT_CLI_BAT_CONTENT
                content = content.replace("${PROJ_NAME}", proj_name.upper())
                # Use the windows versionq below:
                content = content.replace("${PY_VERSION}", py_vers['windows'])
                content = content.replace("${ZIP_VERSION}", sevenzip_vers['windows'])
                self.write_text_file(content, dest_file)</sxh>

=> And that is basically all I had to update: with that I can now create subproject with the NervProj framework that have their own python environment 👍!