mpsd-software-environment.py

#!/usr/bin/env python3

"""mpsd-software-environment: tool for installation of toolchains."""

import argparse
import datetime
import logging
import os
import subprocess
import sys
import time
from pathlib import Path
from typing import List, Tuple, Union
import re

# If 'rich' is available ("pip install rich" or "apt-get install python3-rich"),
# then use coloured output, otherwise proceed as before
try:
    import rich.logging
except ModuleNotFoundError:
    rich_available = False
else:
    rich_available = True


about_tool = """
Build toolchains using Spack.\n

This function builds toolchains for MPSD-HPC at the appropriate directory, \n
for given system architecture and MPSD software stack version.\n
The toolchains
are built using the bash script spack_setup.sh, and the results are logged. """

call_date_iso = (
    datetime.datetime.now().replace(microsecond=0).isoformat().replace(":", "-")
)
config_vars = {
    #  kept inside the mpsd_release folder
    "cmd_log_file": "script_execution_summary.log",
    #  Metadata tags
    "metadata_tag_open": "!<meta>",
    "metadata_tag_close": "</meta>!",
    "spack_environments_repo": "https://gitlab.gwdg.de/mpsd-cs/spack-environments.git",
}


def create_log_file_names(
    mpsd_release: str,
    microarch: str,
    action: str,
    date: str = call_date_iso,
    toolchain: str = None,
) -> Union[str, None]:
    """Create log file names.

    This function creates the log file names for either the installer or
    the build log files.

    If a toolchain is given, then the build log file name is created.
    if no toolchain is given, then the installer log file name is created.
    The installer log file hosts the logs of the installer script, while
    the build log file hosts the logs of the build process as generated by the
    spack_setup.sh script.

    Parameters
    ----------
    mpsd_release : str
        MPSD software stack version
    microarch : str
        system architecture
    date : str
        date of the call ins iso format
    action : str
        action performed (install,remove,reinstall,prepare,status)
        only install and remove are valid for build log file.
    toolchain : str
        toolchain name (only for build log file)

    Returns
    -------
    str or None
        log file name
        installer_log_file_name or build_log_file_name depending on the
        parameters given.
        If the action is not one that changes the files on disk ( info only actions)
        then None is returned.
    """
    if toolchain:
        # if toolchain is given, then  we build the build_log_file_name
        if action in ["install", "remove"]:
            log_file_name = (
                f"{mpsd_release}_{microarch}_{date}_BUILD_{toolchain}_{action}.log"
            )
        else:
            return None
    else:
        # if toolchain is not given, then we build the installer_log_file_name
        log_file_name = f"{mpsd_release}_{microarch}_{date}_APEX_{action}.log"

    return log_file_name


def log_metadata(key: str, value: str) -> None:
    """Log metadata to the log file.

    This function logs metadata to the log file. The metadata is
    enclosed in a tag, so that it can be easily found in the log file.
    logging module is used to write the metadata to the log file.

    Parameters
    ----------
    key : str
        key of the metadata
    value : str
        value of the metadata
    returns : None
    """
    logging.info(
        f"{config_vars['metadata_tag_open']}{key}:{value}{config_vars['metadata_tag_close']}"
    )


def read_metadata_from_logfile(logfile: Union[str, Path]) -> dict:
    """Read metadata from the log file.

    This function reads metadata from the log file. The metadata is
    enclosed in a tag, so that it can be easily found in the log file.

    Parameters
    ----------
    logfile : str or Path
        log file name
    returns : dict
        dictionary containing the metadata
    """
    with open(logfile, "r") as f:
        log_text = f.read()
    # check for all data that matches the regex
    # metadata_tag_open {key}:{value} metadata_tag_close
    # and return a dictionary with all the matches
    return {
        match.group(1): match.group(2)
        for match in re.finditer(
            f"{config_vars['metadata_tag_open']}(\w+):(\w+){config_vars['metadata_tag_close']}",
            log_text,
        )
    }


def get_installer_log_file_path(mpsd_release: str, cmd: str, root_dir: str) -> str:
    """Get installer log file path."""
    # Get machine configs
    os.environ.get("MPSD_OS", "UNKNOWN_OS")
    microarch = get_native_microarchitecture()
    # parse logging first
    # decide the log_file_name
    installer_log_name = create_log_file_names(
        mpsd_release=mpsd_release, microarch=microarch, action=cmd
    )
    log_folder = root_dir / mpsd_release / "logs"
    # if the log_folder dosent exist, dont log this message if
    #  the command is a info-only command
    if cmd not in ["status", "available"]:
        if not os.path.exists(log_folder):
            os.makedirs(log_folder)
        installer_log_file = log_folder / installer_log_name
    else:
        installer_log_file = None
    return installer_log_file


def set_up_logging(loglevel="warning", file_path=None):
    """Set up logging.

    This function sets up the logging configuration for the script.
    It configures the log level, log format, and log handlers
    for both file and console(=shell) output.


    Parameters
    ----------
    loglevel : str or int
       Loglevels are:
         - warning (default): only print statements if something is unexpected
         - info (show more detailed progress)
         - debug (show very detailed output)
    file_path : str
         - filename to save logging messages into

    If loglevel is 'debug', save line numbers in log messages.

    Returns
    -------
    None.

    Logger instances are generally not passed around, but retrieved from the
    logging module as shown below (they are singletons).

    We provide two loggers:

    1. log = logging.getLogger('')

       This is the 'root' logger. It uses a RichHandler if rich is available for
       output to the shell, otherwise plain text.

       Typical use:

       log.debug("...")
       log.info("...")
       log.warn("...")

       Equivalent to

       logging.debug("...")
       logging.info("...")

    2. print_log = logging.getlogger('print')

       This uses the logging module to issue the message, but prints without
       any further markup (i.e. no date, loglevel, line number, etc). Think
       PRINT via the LOGging module.

       We use this as a replacement for the print function (i.e. for messages
       that should not be affected by logging levels, and which should always
       be printed).

       Typical and intended use:

       print_log.info("Available toolchains are ...")

       The major difference from the normal print command is that the output
       will be send to the stdout (as for print) AND the file with name
       filename, so that these messages appear in the log file together with
       normal log output.

    """
    # convert loglevel string into loglevel as number
    log_level_numeric = getattr(logging, loglevel.upper(), logging.WARNING)
    if not isinstance(log_level_numeric, int):
        raise ValueError("Invalid log level: %s" % loglevel)

    # set up the main logger ("root" logger)
    logger = logging.getLogger("")
    # - "logger" logs everything
    # - we use loglevel at handler level to write everything to file
    # - and filter using  log_level_numeric (as the user provides) to
    #   send logging messages to the console
    logger.setLevel(0)

    # the handler determines where the logs go: stdout/file
    if rich_available:
        # https://rich.readthedocs.io/en/stable/logging.html
        shell_handler = rich.logging.RichHandler()
        # rich handler provides metadata automatically:
        logging_format = "%(message)s"
        # for shell output, only show time (not date and time)
        shell_formatter = logging.Formatter(logging_format, datefmt="[%X]")
    else:
        shell_handler = logging.StreamHandler()
        # include line numbers in output if level is DEBUG
        linenumbers = " %(lineno)4d" if log_level_numeric == logging.DEBUG else ""
        logging_format = "%(asctime)s %(levelname)7s" + linenumbers + "  |  %(message)s"
        shell_formatter = logging.Formatter(logging_format)

    # here we hook everything together
    shell_handler.setFormatter(shell_formatter)
    # use the log_level_numeric to decide how much logging is sent to shell
    shell_handler.setLevel(log_level_numeric)

    # Here we set the handlers of the RootLogger to be just the one we want.
    # The reason is that the logging module will add a <StreamHandler <stderr>
    # (NOTSET)> handler if logging.info/logging.debug/... is used before we
    # come across this line. And we do not want that additional handler.
    logger.handlers = [shell_handler]

    # if filename provided, write log messages to that file, too.
    if file_path:
        file_handler = logging.FileHandler(file_path)
        # if we have a file, we write all information in there.
        # We could change the level, for example restrict to only DEBUG and above with
        # file_handler.setLevel(logging.DEBUG)
        file_logging_format = "%(asctime)s %(levelname)7s %(lineno)4d  |  %(message)s"
        file_formatter = logging.Formatter(file_logging_format, datefmt="[%X]")
        file_handler.setFormatter(file_formatter)
        logger.addHandler(file_handler)

    #
    # new logger for printing
    #
    print_log = logging.getLogger("print")
    print_log.setLevel(logging.INFO)
    print_log.propagate = False
    # create formatter 'empty' formatter
    formatter = logging.Formatter("%(message)s")

    # create, format and add handler for shell output
    ch = logging.StreamHandler()
    ch.setFormatter(formatter)
    print_log.addHandler(ch)

    # if filename provided, write output of print_log to that file, too
    if file_path:
        # create, format and add file handler
        fh = logging.FileHandler(file_path)
        fh.setFormatter(formatter)
        print_log.addHandler(fh)

    #
    # short message
    #
    logging.debug(
        f"Logging has been setup, loglevel={loglevel.upper()} "
        + f"{file_path=} {rich_available=}"
    )


# Helper class to change directory via context manager
class os_chdir:
    """The os_chdir class is a context manager.

    It changes the current directory to a specified directory
    and returns to the original directory after execution.
    """

    def __init__(self, new_dir):
        """Initialize, save original directory."""
        self.new_dir = new_dir
        self.saved_dir = os.getcwd()

    def __enter__(self):
        """Go to target directory (main action for context)."""
        os.chdir(self.new_dir)

    def __exit__(self, exc_type, exc_val, exc_tb):
        """On exist we return to original directory."""
        os.chdir(self.saved_dir)


def run(*args, counter=[0], **kwargs):
    """
    Run a subprocess and log the call.

    Convenience function to call `subprocess.run` and provide some metadata
    about the call.

    Parameters
    ----------
    args : tuple
        passed on to subprocess.run(*args). For example
        ("ls -l") or (["ls", "-l"])
    counter : TYPE, optional
        list with one integer, starting from [0].
        This is (a Python hack) to count the number of
        calls of this function, so the different calls of subprocess.run
        are easier to follow in the log files.
    kwargs : dict
        keyword-value arguments to be passed to subprocess.run. For example,
        `shell=True`.

    Returns
    -------
    process : subprocess.CompletedProcess
        CompletedProcess object as returned by `subprocess.run` .

    Examples
    --------
    >>> run(['date', '+%Y-%m-%d'])
    ##-03 Starting subprocess.run(['date', '+%Y-%m-%d']) with options
    ##-03   getcwd=/Users/fangohr/git/mpsd-software-environments
    ##-03   COMMAND=date +%Y-%m-%d
    2023-05-30
    ##-03   Completed in 0.0054s.
    ##-03
    CompletedProcess(args=['date', '+%Y-%m-%d'], returncode=0)

    >>> run(['date +%Y-%m-%d'], shell=True)
    ##-04 Starting subprocess.run(['date +%Y-%m-%d']) with options shell=True
    ##-04   getcwd=/Users/fangohr/git/mpsd-software-environments
    ##-04   COMMAND=date +%Y-%m-%d
    2023-05-30
    ##-04   Completed in 0.0069s.
    ##-04
    CompletedProcess(args=['date +%Y-%m-%d'], returncode=0)
    """
    # token is printed in front of every meta-data line - useful for
    # searching the logs. Starts with "##-00", then "##-01", ...
    token = f"##-{counter[0]:02d}"

    counter[0] += 1  # increase counter

    # make command nicely readable: ["ls", "-l"] -> "ls -l"
    assert isinstance(args, tuple)
    assert len(args) == 1
    arg = args[0]
    # either args is a tuple containing a string | Example: ('ls -1',)
    if isinstance(arg, str):
        command = arg
        # or we have a tuple containing a list of strings.
        # Example: (['ls', '-1'],)
    elif isinstance(arg, list):
        command = " ".join(arg)
    else:
        # we do not expect this to happen
        raise NotImplementedError(f"{arg=}, {args=}")

    # make options (such as `shell=True`) nicely readable
    options = ", ".join([f"{key}={value}" for key, value in kwargs.items()])

    # provide information about upcoming subprocess.run call
    logging.info(f"{token} Starting subprocess.run('{command}') with options {options}")
    logging.debug(f"""{token}   getcwd={os.getcwd()}""")
    logging.debug(f"""{token}   subprocess.run("{arg}")""")

    time_start = time.time()
    process = subprocess.run(*args, **kwargs)
    execution_time = time.time() - time_start

    logging.debug(f"{token}   {process=}")
    logging.debug(f"{token}   Completed in {execution_time:.4f}s.")
    logging.debug(f"{token}")  # near-empty line to make reading logs easier
    return process


def record_script_execution_summary(
    mpsd_release: str, root_dir: str, msg: str = None, **kwargs
) -> None:
    """
    Log the command used to build the toolchains.

    It also logs information about the software environment installer branch,
    the Spack environments branch, and the commit hashes of each.
    It also logs steps taken
    in the install process using the optional message argument.

    Parameters
    ----------
    - mpsd_release : str
        The name of the release to install toolchains for.
    - root_dir : str
        The path to the directory where the scripts are located.
    - msg : str, optional
        An optional message to log in the command log file.
    - **kwargs : dict
        A dictionary with values for
        - spe_branch : str
            The name of the Spack environments branch.
        - spe_commit_hash : str
            The commit hash of the Spack environments branch.

    Returns
    -------
    - None
    """
    release_base_dir = root_dir / mpsd_release

    # Write to the log file with the following format
    # --------------------------------------------------
    # 2023-02-29T23:32:01, install-software-environment.py --release 23b --install ALL
    # Software environment installer branch: script_branch (commit hash: \
    #    script_commit_hash)
    # Spack environments branch: dev-23a (commit hash: spe_commit_hash)
    # MSGs
    with os_chdir(release_base_dir):
        with open(config_vars["cmd_log_file"], "a") as f:
            if msg:
                # Write the message to the log file
                f.write(msg + "\n")
            else:
                # Write the header
                f.write("-" * 50 + "\n")

                # Gather data to log
                # call statement:
                cmd_line = " ".join(sys.argv)
                # script branch and commit hash
                with os_chdir(root_dir):
                    script_branch = (
                        run(
                            ["git", "rev-parse", "--abbrev-ref", "HEAD"],
                            stdout=subprocess.PIPE,
                            check=True,
                        )
                        .stdout.decode()
                        .strip()
                    )
                    script_commit_hash = (
                        run(
                            ["git", "rev-parse", "--short", "HEAD"],
                            stdout=subprocess.PIPE,
                            check=True,
                        )
                        .stdout.decode()
                        .strip()
                    )
                # spack-environments branch and commit hash from kwargs
                spe_branch = kwargs.get("spe_branch", None)
                spe_commit_hash = kwargs.get("spe_commit_hash", None)

                # Write to log file
                f.write(f"{datetime.datetime.now().isoformat()}, {cmd_line}\n")
                f.write(
                    f"Software environment installer branch: {script_branch} "
                    f"(commit hash: {script_commit_hash})\n"
                )
                f.write(
                    f"Spack environments branch: {spe_branch} "
                    f"(commit hash: {spe_commit_hash})\n"
                )


def clone_repo(
    target_path: Path, repo_url: str, branch=None
) -> None:
    """Clone repo locally. Optionally checkout a branch.

    Parameters
    ----------
    target_path : Path
      Where to check the repository out to
    repo_url: str
      where to clone the git repository from
    branch: str (defaults to None)
      if provided, checkout this branch after cloning
    """
    if not target_path.exists():
        target_path.mkdir()

    with os_chdir(target_path):
        run(
            ["git", "clone", repo_url, "."],
            check=True,
        )
    if branch:
        with os_chdir(target_path):
            # Git fetch and checkout the release branch and git pull
            # to be sure that the resulting repo is up to date
            run(["git", "fetch", "--all"], check=True)
            checkout_result = run(["git", "checkout", branch])

            if checkout_result.returncode != 0:
                msg = f"Couldn't find {branch=}\n"

                branches_result = run(
                    ["git", "branch", "-a"], check=True, capture_output=True
                )
                branches_list = branches_result.stdout.decode().split("\n")
                # strip off 'remotes/origin' (needs Python 3.9):
                branches_list = [
                    b.strip().removeprefix("remotes/origin/") for b in branches_list
                ]
                msg += f"Available branches are {branches_list}"
                logging.error(msg)
                raise Exception(msg, branches_result)
            else:
                run(["git", "pull"], check=True)


def get_release_info(mpsd_release: str, root_dir: Path) -> Tuple[str, str, List[str]]:
    """
    Get information about the specified release.

    Get information about the specified release, such as the branch and commit hash
    of the Spack environments repository and the available toolchains.

    Parameters
    ----------
    mpsd_release : str
        The name of the release to get information for.
    root_dir : pathlib.Path
        The base directory where releases are stored.

    Returns
    -------
    spe_branch : str
        The name of the branch for the Spack environments repository.
    spe_commit_hash : str
        The commit hash for the Spack environments repository.
    available_toolchains : list
        A list of strings representing the available toolchains for the release.

    Raises
    ------
    FileNotFoundError
        If the release directory does not exist.
    """
    # Get the info for release
    release_base_dir = root_dir / mpsd_release
    if not os.path.exists(release_base_dir):
        logging.debug(f"get_release_info({mpsd_release=}, {root_dir=})")
        raise FileNotFoundError(
            f"{release_base_dir} does not exist.\n"
            f"Hint: `prepare {mpsd_release}` may fix this."
        )
    with os_chdir(release_base_dir):
        with os_chdir("spack-environments"):
            # Get the branch and commit hash of the spack-environments repo
            spe_commit_hash = (
                run(["git", "rev-parse", "HEAD"], stdout=subprocess.PIPE, check=True)
                .stdout.decode()
                .strip()
            )
            spe_branch = (
                run(
                    ["git", "rev-parse", "--abbrev-ref", "HEAD"],
                    stdout=subprocess.PIPE,
                    check=True,
                )
                .stdout.decode()
                .strip()
            )
            available_toolchains = os.listdir("toolchains")
    return spe_branch, spe_commit_hash, available_toolchains


def prepare_environment(mpsd_release: str, root_dir: Path) -> List[str]:
    """
    Create the directory structure for the given MPSD release.

    It does the following steps:
    Clones the spack-environments repository.
    Determines the branch and commit hash of the spack-environments repository
    and the available toolchains.
    Logs the command usage.

    Parameters
    ----------
    mpsd_release : str
        The name of the MPSD release to prepare the environment for.
    root_dir : pathlib.Path
        The base directory to create the release folder and
        clone the spack-environments repository into.

    Returns
    -------
    available_toolchains : list
        A list of available toolchains for the given MPSD release.
    """
    # Creates the directory structure for the specified release and clone the
    # Spack environments repository if it doesn't exist:

    # Create the directory structure for the release
    release_base_dir = root_dir / mpsd_release
    release_base_dir.mkdir(parents=True, exist_ok=True)
    repo_path = release_base_dir / "spack-environments"
    if repo_path.exists():
        logging.debug(f"directory {repo_path} exists already, not touching")
    else:
        repo_url = config_vars["spack_environments_repo"]
        logging.info(f"cloning repository {repo_path} from {repo_url}")
        clone_repo(repo_path, repo_url, branch=mpsd_release)

    spe_branch, spe_commit_hash, available_toolchains = get_release_info(
        mpsd_release, root_dir
    )
    record_script_execution_summary(
        mpsd_release, root_dir, spe_branch=spe_branch, spe_commit_hash=spe_commit_hash
    )
    return available_toolchains


def get_native_microarchitecture():
    """Return native microarchitecture.

    On MPSD machines, there should be an environment variable "microarch".
    We try to read that. If it fails, we use the 'archspec cpu' command.
    If that fails, we ask the user to install it.

    Returns
    -------
    microarch : str

    Example
    -------
    >>> get_native_microarchitecture()
    'haswell'
    """
    # attempt to get MICRO_ARCH from environment variable (should work on
    # MPSD_HPC and MPSD linux laptops). If not defined, return
    # "UNKNOWN_MICROARCH"
    microarch = os.environ.get("MPSD_MICROARCH", "UNKNOWN_MICROARCH")

    # if we have not found the microarchitecture environment variable,
    # try calling archspec
    if microarch == "UNKNOWN_MICROARCH":
        logging.debug(
            "Couldn't find MPSD_MICROARCH environment variable. Will try archspec."
        )
        try:
            process = run(["archspec", "cpu"], stdout=subprocess.PIPE, text=True)
        except FileNotFoundError as e:
            logging.debug(f"Call of 'archspec cpu' failed: {e=}")
            # Presumably 'archspec' is not installed.
            msg = "Please install archspec, for example via 'pipx install archspec'.\n"
            msg += "The command we need to execute is 'archspec cpu'.\n"
            msg += "Documentation of package: https://archspec.readthedocs.io/"

            logging.error(msg)
            sys.exit(1)
        else:  # we have found archspec and executed it
            if process.returncode == 0:  # sanity check
                microarch = process.stdout.strip()
                logging.debug(
                    f"Found microarchitecture from 'archspec cpu' to be '{microarch}'"
                )
                assert len(microarch) > 0  # sanity check
            else:
                raise ValueError(
                    f"Some error occurred when calling 'archspec cpu': {process=}"
                )

    # at this point, we have determined the microarchitecture
    log_metadata("microarchitecture", microarch)
    return microarch


def install_environment(
    mpsd_release: str,
    toolchains: List[str],
    root_dir: Path,
    force_reinstall: bool = False,
    enable_build_cache: bool = False,
) -> None:
    """
    Install the specified MPSD release and toolchains.

    The function installs the toolchain to the specified directory, using Spack.

    Parameters
    ----------
    mpsd_release : str
        A string representing the MPSD release version.
    toolchains : list of str
        A list of strings representing the toolchains to install
        (e.g., "foss2021a-mpi", "global_generic", "ALL").
    root_dir : pathlib.Path
        A Path object representing the path to the directory where
        the release and toolchains will be installed.
    force_reinstall : bool, optional
        A boolean indicating whether to force a reinstallation
        even if the release and toolchains already exist. Defaults to False.
    enable_build_cache : bool, optional
        A boolean indicating whether to build the build cache
        when installing toolchains. Defaults to False.

    Raises
    ------
    ValueError
        If a requested toolchain is not available in the specified release.

    Returns
    -------
    None
    """
    logging.info(
        f"Installing release {mpsd_release} with toolchains {toolchains} "
        f"to {root_dir}"
    )

    # Set required variables
    release_base_dir = root_dir / mpsd_release
    microarch = get_native_microarchitecture()
    toolchain_dir = release_base_dir / microarch
    toolchain_dir.mkdir(parents=True, exist_ok=True)
    spack_setup_script = release_base_dir / "spack-environments" / "spack_setup.sh"
    install_flags = []
    if not enable_build_cache:
        install_flags.append("-b")

    # run the prepare_environment function
    available_toolchains = prepare_environment(mpsd_release, root_dir)
    # Ensure that the requested toolchains are available in the release
    if toolchains == "ALL":
        toolchains = available_toolchains
    elif toolchains == "NONE":
        # No toolchains requested, so we only create the env and print the
        # list of available toolchains
        logging.warning(
            "No toolchains requested. Available toolchains for release "
            f"{mpsd_release} are: \n {available_toolchains}"
        )
        print_log = logging.getLogger("print")
        print_log.info(f"{available_toolchains=}")
        return

    for toolchain in toolchains:
        if toolchain not in available_toolchains:
            # TODO: add to message how toolchains can be found
            msg = f"Toolchain '{toolchain}' is not available in release {mpsd_release}."
            logging.error(msg)
            sys.exit(1)

    # Install the toolchains
    with os_chdir(toolchain_dir):
        # run spack_setup_script with the toolchains as arguments
        # if the log folder doesn't exist, create it
        if not os.path.exists("logs"):
            os.mkdir("logs")
        for toolchain in toolchains:
            # Set the install log file name from create_log_file_names
            build_log_file_name = create_log_file_names(
                mpsd_release, microarch, "install", toolchain=toolchain
            )
            build_log_folder = release_base_dir / "logs"
            build_log_path = build_log_folder / build_log_file_name
            # if logs folder dosent exist, create it
            if not os.path.exists(build_log_folder):
                os.makedirs(build_log_folder)

            logging.info(f"Installing toolchain {toolchain} to {toolchain_dir}")

            # log the command
            record_script_execution_summary(
                mpsd_release,
                root_dir,
                msg=f"installing {toolchain} and logging at {build_log_path}",
            )
            record_script_execution_summary(
                mpsd_release,
                root_dir,
                msg=(
                    f"CMD: bash {spack_setup_script} {' '.join(install_flags)} "
                    f"{toolchain}"
                ),
            )
            run(
                f"bash {spack_setup_script} {' '.join(install_flags)} {toolchain} 2>&1 "
                f"| tee -a {build_log_path} ",
                shell=True,
                check=True,
            )


def remove_environment(release, toolchains, target_dir):
    """Remove release from installation."""
    msg = f"Removing release {release} with toolchains {toolchains} from {target_dir}"
    logging.info(msg)
    raise NotImplementedError(msg)


def start_new_environment(release, from_release, target_dir):
    """Start new MPSD software environment version."""
    msg = f"Starting new release {release} from {from_release} to {target_dir}"
    logging.info(msg)
    raise NotImplementedError(msg)


def main():
    """Execute main entry point."""
    parser = argparse.ArgumentParser(description=about_tool)
    parser.add_argument(
        "--log",
        "-l",
        dest="loglevel",
        choices=["warning", "info", "debug"],
        required=False,
        default="warning",
        help="Set the log level",
    )

    subparsers = parser.add_subparsers(
        dest="action", title="actions", description="valid actions", required=True
    )
    subparsers.required = True
    list_of_cmds = [
        ("prepare", "Prepare the environment for installation on the disk"),
        ("install", "Install a software environment"),
        ("reinstall", "Reinstall a software environment"),
        ("remove", "Remove a software environment or toolchains from an environment"),
        ("start-new", "Start a new software environment version"),
    ]
    for cmd, help_text in list_of_cmds:
        subp = subparsers.add_parser(cmd, help=help_text)

        if cmd == "start-new":
            subp.add_argument(
                "--from-release",
                dest="from_release",
                type=str,
                required=True,
                help="Release version to start from",
            )
            subp.add_argument(
                "--to-release",
                dest="to_release",
                type=str,
                required=True,
                help="Release version to create",
            )

        else:
            subp.add_argument(
                "release",
                type=str,
                help="Release version to prepare, install, reinstall or remove",
            )
            if cmd in ["install", "reinstall", "remove"]:
                # "install" command needs additional documentation
                tool_chain_help = (
                    f"Pass a list of toolchains to command {cmd}. "
                    "Use '--toolchains ALL' to "
                    f"{cmd} all toolchains. If '--toolchain' is not "
                    "specified, list available toolchains for the release "
                    "(after environment has been prepared if not done yet)."
                )

                subp.add_argument(
                    "--toolchains",  # first option defines attribute
                    # name `args.toolchains` in `args = parser_args()`
                    "--toolchain",  # allow singular as alternative
                    # (-> creates attribute `args.toolchains` if used)
                    type=str,
                    dest="toolchains",
                    nargs="+",
                    default="NONE",
                    help=tool_chain_help,
                )
                subp.add_argument(
                    "--enable-build-cache",
                    action="store_true",
                    help=(
                        "Enable Spack build cache. Useful for reinstallation but "
                        "consumes time and disk space."
                    ),
                )
    # Carry out the action
    args = parser.parse_args()

    # target dir is the place where this script exists. the
    root_dir = Path(os.path.dirname(os.path.realpath(__file__)))

    set_up_logging(
        args.loglevel,
        get_installer_log_file_path(args.release, args.action, root_dir),
    )

    # Check the command and run related function
    if args.action == "remove":
        remove_environment(args.release, args.toolchains, root_dir)
    elif args.action == "start-new":
        start_new_environment(args.from_release, args.to_release, root_dir)
    elif args.action == "install":
        install_environment(
            args.release, args.toolchains, root_dir, False, args.enable_build_cache
        )
    elif args.action == "prepare":
        prepare_environment(args.release, root_dir)


if __name__ == "__main__":
    main()