Mini Shell

"""
Support for hadoop

:maintainer: Yann Jouanin <yann.jouanin@intelunix.fr>
:maturity: new
:depends:
:platform: linux


"""

import salt.utils.path

__authorized_modules__ = ["version", "namenode", "dfsadmin", "dfs", "fs"]


def __virtual__():
    """
    Check if hadoop is present, then load the module
    """
    if salt.utils.path.which("hadoop") or salt.utils.path.which("hdfs"):
        return "hadoop"
    return (
        False,
        "The hadoop execution module cannot be loaded: hadoop or hdfs binary not in"
        " path.",
    )


def _hadoop_cmd(module, command, *args):
    """
    Hadoop/hdfs command wrapper

    As Hadoop command has been deprecated this module will default
    to use hdfs command and fall back to hadoop if it is not found

    In order to prevent random execution the module name is checked

    Follows hadoop command template:
       hadoop module -command args
    E.g.: hadoop dfs -ls /
    """
    tool = "hadoop"
    if salt.utils.path.which("hdfs"):
        tool = "hdfs"

    out = None
    if module and command:
        if module in __authorized_modules__:
            mappings = {
                "tool": tool,
                "module": module,
                "command": command,
                "args": " ".join(args),
            }
            cmd = "{tool} {module} -{command} {args}".format(**mappings)
            out = __salt__["cmd.run"](cmd, python_shell=False)
        else:
            return "Error: Unknown module"
    else:
        return "Error: Module and command not defined"
    return out


def version():
    """
    Return version from hadoop version

    CLI Example:

    .. code-block:: bash

        salt '*' hadoop.version
    """
    module = "version"
    out = _hadoop_cmd(module, True).split()
    return out[1]


def dfs(command=None, *args):
    """
    Execute a command on DFS

    CLI Example:

    .. code-block:: bash

        salt '*' hadoop.dfs ls /
    """
    if command:
        return _hadoop_cmd("dfs", command, *args)
    else:
        return "Error: command must be provided"


def dfsadmin_report(arg=None):
    """
    .. versionadded:: 2019.2.0

    Reports basic filesystem information and statistics. Optional flags may be used to filter the list of displayed DataNodes.

    arg
        [live] [dead] [decommissioning]

    CLI Example:

    .. code-block:: bash

        salt '*' hadoop.dfsadmin -report
    """
    if arg is not None:
        if arg in ["live", "dead", "decommissioning"]:
            return _hadoop_cmd("dfsadmin", "report", arg)
        else:
            return (
                "Error: the arg is wrong, it must be in ['live', 'dead',"
                " 'decommissioning']"
            )
    else:
        return _hadoop_cmd("dfsadmin", "report")


def dfs_present(path):
    """
    Check if a file or directory is present on the distributed FS.

    CLI Example:

    .. code-block:: bash

        salt '*' hadoop.dfs_present /some_random_file

    Returns True if the file is present
    """
    cmd_return = _hadoop_cmd("dfs", "stat", path)
    match = "No such file or directory"
    return False if match in cmd_return else True


def dfs_absent(path):
    """
    Check if a file or directory is absent on the distributed FS.

    CLI Example:

    .. code-block:: bash

        salt '*' hadoop.dfs_absent /some_random_file

    Returns True if the file is absent
    """
    cmd_return = _hadoop_cmd("dfs", "stat", path)
    match = "No such file or directory"
    return True if match in cmd_return else False


def namenode_format(force=None):
    """
    Format a name node

    .. code-block:: bash

        salt '*' hadoop.namenode_format force=True
    """
    force_param = ""
    if force:
        force_param = "-force"

    return _hadoop_cmd("namenode", "format", "-nonInteractive", force_param)