fabric/modules/utils.py

import os
import sys
import errno
import logging

import fabric.contrib.files

from contextlib import contextmanager as _contextmanager
from fabric.api import env, prefix, local
from fabric.operations import run, sudo


def printvar(name, value, exit=False):
    """
    debug helper method to print a variable from within a process

    :parameter name: name of the variable we are printing out
    :type name:  str

    :parameter value: the value of the variable we want to print
    :type value:  str

    :parameter exit: determines whether or not we exit the program at
        this point. defaults to false
    :type exit:  bool
    """
    print("%s : %s" % (name, value))
    if exit:
        sys.exit()


def printerr(message="", errcode=-2, exit=True):
    """
    debug helper method thats prints error message and error code then exits

    :parameter message: the error message we want to print out.
        defaults to empty string.
    :type message:  str

    :parameter errcode: the code of the error
    :type errcode: int

    :parameter exit: determines whether or not we exit the program at
        this point. defaults to True
    :type exit:  bool
    """

    message = "Error\n\t{message}\n\tExiting with code: {errcode}\n".format(
        message=message, errcode=errcode)

    print
    print(message)
    print
    sys.exit(errcode)


def loggify(module, func, prefix=""):
    """
    I'm tired of rewriting this logging code in every single function, so I
    decided to just dump it here, and return a logger that can be used and
    thrown away when it's done

    :parameter module: name of the module being used, ie 'nginx', 'deploy', etc
    :type module:  str

    :parameter func: the name of the function this logger is going to be used
        in
    :type func:  str

    :parameter prefix: anything you want to add to the front of the logger,
        ie \'\\n\'. defaults to an empty string.
    :type prefix:  str

    :return: a logging object
    :rtype: object
    """

    loggername = '{module}.{func}'.format(
        module=module, func=func)

    str_logging = '{prefix}%(levelname)s: {loggername} %(message)s'.format(
        prefix=prefix,
        loggername=loggername)

    logging.basicConfig(
        format=str_logging,
        level=logging.DEBUG)

    return logging.getLogger(loggername)


def print_console(string, prepend="\n\n", append="\n\n", sep="-", numsep=44,
                  exit_program=False, exit_code=0):
    """
    helper function to take a string, and format it so it prints to the console
    in a way that is pleasing to the eye.

    :parameter string: the string to be printed
    :type string:  str

    :parameter prepend: defaults to two line spaces, can be anything
    :type string:  str

    :parameter append: defaults to two lines spaces after the string is printed
    :type append:  str

    :parameter sep: the character used to print out one line above the string
        and one line after
    :type sep: str

    :parameter numsep: number of times the separator is printed out on a line
    :type numsep: int

    :parameter exit_program: whether to exit the program after printing the
        message.  defaults to False
    :type exit_program: bool

    :parameter exit_code: what exit code to use if we exit the program after
        printing the message. defaults to 0
    :type exit_code: int
    """

    print(prepend)

    if sep:
        print(sep * numsep)

    print(string)

    if sep:
        print(sep * numsep)

    print(append)

    if exit_program:
        import sys
        sys.exit(exit_code)


def print_debug(debugstr, module, function):
    """
    debug helper method to print out a debug string, the name of the module,
    and the function it is located in.

    The message will be printed out in the form <debugstr>:<module>:<function>

    :parameter debugstr: the debugging message we want to print
    :type debugstr:  str

    :parameter module: the name of the module we are in
    :type module:  str

    :parameter function: the name of the function we are in
    :type function:
    """

    print("%s:%s:%s" % (module, function, debugstr))


def executize(config_execute='local'):
    """
    creates an executor to run commands. returns one of the following methods
    fabric.api.local, fabric.operations.run or fabric.operations.sudo

    :parameter config_execute: values can be either 'sudo', 'run', or 'local'.
        defaults to 'local'.
    :type config_execute:  str

    :return: the fabric command corresponding to the string value
        in config_execute, either a sudo, a run or a local executor
    """

    if config_execute == 'sudo':
        _execute = sudo
    elif config_execute == 'run':
        _execute = run
    elif config_execute == 'local':
        _execute = local
    else:
        errmsg = "did not enter a correct value of 'sudo', 'run' or" \
            " 'local' to executize.\nExiting."
        printerr(message=errmsg, errcode=-2)

    return _execute


def booleanize(value):
    """
    take the argument and return it as either True or False

    if the argument is neither, throw a TypeError explaining that the value
    given cannot be booleanized

    :parameter value: takes values of y, n, yes, no, true, false,
        1 or 0
    :type value:  str

    :return: converts value to True or False.  Note 1 is
        considered True and 0 is False
    :rtype: bool
    """

    true_values = ("y", "yes", "true", "1")
    false_values = ("n", "no", "false", "0")

    if isinstance(value, bool):
        return value

    if value.lower() in true_values:
        return True

    elif value.lower() in false_values:
        return False

    raise TypeError("Cannot booleanize ambiguous value '%s'" % value)


def ensure_dir(dirpath):
    """
    Create a directory if it does not exists.

    Raises an OSError if there is a problem

    :parameter dirpath: directory path
    :type dirpath:  str

    """
    try:
        if not os.path.exists(dirpath):
            print("creating directory: %s" % dirpath)
            os.makedirs(dirpath)

    except OSError as e:
        if e.errno != errno.EEXIST:
            print("Error occurred while creating directory: %s"
                  % dirpath)
            raise


def ensure_file(filepath):
    """
    Simulates linux 'touch' command

    :parameter filepath: name of the file we want to create. Note this
        must include the full path and filename
    :type filepath:  str
    """
    if not os.path.exists(filepath):
        open(filepath, 'w').close()


def upload_template(filename, destination, context, use_jinja,
                    use_sudo, backup, template_dir, debug=False):
    """
    helper wrapper method to upload a template

    it wraps around fabric.contrib.files.upload_template method.
    See https://docs.fabfile.org/en/1.11/api/contrib/files.html

    :parameter filename: the full path to the filename if we are not
        using jinja, otherwise using template_dir and just the filename
        this file will be interpolated using the given context and
        uploaded to the remote host
    :type filename:  str

    :parameter destination: remote file path to place the file
        (includes filename)
    :type destination:  str

    :parameter context: variable context
    :type context: dict

    :parameter use_jinja: whether we are using jinja template system or not.
        Templates will be loaded from the invoking users' current working
        directory or by template_dir
    :type use_jinja:  bool

    :parameter use_sudo: whether we are using sudo to place the file.
        By default the file will be copied as the logged in user
    :type use_sudo:  bool

    :parameter backup: if the destination file already exists, create a backup
        of it with the extension .bak
    :type backup:  bool

    :parameter template_dir: path to the template directory that is used if
        jinja is true.  directory where the file is located
    :type template_dir:  str

    :parameter debug: if true, just print out the command we are using to
        invoke the fabric upload_template method. defaults to False
    :type debug:  bool
    """

    if env.debug:
        logging.basicConfig(
            format='\n%(levelname)s: utils.upload_template %(message)s',
            level=logging.DEBUG)

    command_msg = "\n\tupload_template(" \
        "\n\tfilename={filename}," \
        "\n\tdestination={destination_available}," \
        "\n\tcontext={context}," \
        "\n\tuse_jinja={use_jinja}," \
        "\n\tuse_sudo={use_sudo}," \
        "\n\tbackup={backup}," \
        "\n\ttemplate_dir={template_dir})\n".format(
            filename=filename,
            destination_available=destination,
            context=context,
            use_jinja=use_jinja,
            use_sudo=use_sudo,
            backup=backup,
            template_dir=template_dir)

    if debug:
        return command_msg

    else:

        fabric.contrib.files.upload_template(
            filename=filename,
            destination=destination,
            context=context,
            use_jinja=use_jinja,
            use_sudo=use_sudo,
            backup=backup,
            template_dir=template_dir)


def get_upload_template_msg(filename, destination, context, use_jinja,
                            use_sudo, backup, template_dir, debug=False):

    command_msg = "\n\tupload_template(" \
        "\n\tfilename={filename}," \
        "\n\tdestination={destination_available}," \
        "\n\tcontext={context}," \
        "\n\tuse_jinja={use_jinja}," \
        "\n\tuse_sudo={use_sudo}," \
        "\n\tbackup={backup}," \
        "\n\ttemplate_dir={template_dir})\n".format(
            filename=filename,
            destination_available=destination,
            context=context,
            use_jinja=use_jinja,
            use_sudo=use_sudo,
            backup=backup,
            template_dir=template_dir)

    return command_msg


@_contextmanager
def virtualenv_source():
    """
    helper method that sources the virtualenvwrapper for all following commands

    uses python yield command
    """
    configuration = env.config
    venv_bin = configuration.virtualenv.bin

    if venv_bin: 
     venv_activate = f"source {venv_bin}/virtualenvwrapper.sh"
    else:
     venv_activate = "source virtualenvwrapper.sh"

    with prefix(venv_activate):
        yield


@_contextmanager
def virtualenv():
    """
    Context manager for setting the virtual environment for commands.

    This helper method sets up the virtual environment specified in the
    configuration before executing any commands within its context. It uses
    the Python context manager pattern with the `yield` keyword to
    temporarily modify the environment for the duration of the with-block.
    The virtual environment is specified by the name in
    `configuration.virtualenv.name` and is activated using the `workon`
    command.

    Note:
        - This method relies on the Fabric library's `prefix` context manager
          and assumes the use of virtualenvwrapper or a similar tool for
          managing virtual environments.
        - The method expects `configuration.virtualenv.name` to be properly
          set in `env.config`.

    Example Usage:
        with virtualenv():
            run("python manage.py migrate")
    """

    configuration = env.config
    with virtualenv_source():
        with prefix("workon %s" % configuration.virtualenv.name):
            yield

    # with prefix("/bin/bash -c -l 'source %s'" %
    #             configuration.virtualenv.activate):
    #     yield

    # with prefix("/bin/bash -c -l 'source /usr/local/bin/' \
    #       'virtualenvwrapper.sh ' \
    #             '&& workon %s'" % configuration.virtualenv.name):
    #     yield


def generate_template_build_path(section, template_name='conf'):
    """
    helper function to automate creation of build path

    :parameter section: the template section we are building off of
    :type section:  str

    :parameter template_name: by default this is "conf", but can be
        different, for example, the 'database' section has 3 different
        template names
    :type template_name:  str

    :return: a path to where the template should be placed
    """
    import os

    configuration = env.config

    conf_section = getattr(configuration.templates, section)

    conf_section_templatename = getattr(conf_section, template_name)

    build_path = os.path.join(
        conf_section.path.remote,
        'build',
        conf_section_templatename.dst)

    return build_path


def generate_template_files_path(section):
    """
    helper function to automate creation of build path

    :parameter section: the template section we are building off of
    :type section:  str

    :return: a path to where the template jinja file is located
    :rtype: str
    """
    import os

    configuration = env.config

    conf_section = getattr(configuration.templates, section)

    files_path = os.path.join(
        conf_section.path.local,
        'files')

    return files_path


def print_run(command, prefix="\"\n\t", suffix="\n\t\""):
    """
    helper function to print out what a command will actually look like when
    run

    :parameter command: a typical bash command that I want to run
    :type command:  str

    :parameter prefix: prefix that is added to the string, typically done
        for clarity of viewing
    :type prefix:  str

    :parameter suffix: suffix that is added to the string, typically done
        for clarity of viewing
    :type suffix:  str

    :returns: an example of how the command will actually look if run
        on the command line
    :rtype: str
    """

    return "run ({prefix}{command}{suffix})".format(
        prefix=prefix,
        suffix=suffix,
        command=command)


def handle_flag_message(param, message, values=['-h', '--help']):
    """
    if a given parameter is in the given values
    then return the given message

    :parameter param: checks if the given parameter is in
        the values.
    :type param:  str

    :parameter message: the message to print out if true
    :type message:  str

    :parameter values: the values we are checking to see.
        by default this is ['-h', '--help']
    :type values: list

    :return: whether the given param is in values
    :rtype: bool
    """

    if isinstance(param, str):
        if param.lower() in values:
            print(message)
            return True

    return False


def is_help(key):
    """
    helper method to determine if the given key is a help key

    :parameter key: the key we are checking
    :type key:  str

    :return: if key is in -h or --help
    :rtype: bool
    """
    help_keys = ['-h', '--help']

    return key in help_keys


def link_create(path_src, path_dst, debug=False):
    """
    takes a source and destination path, then links it
    if the destination path already exists and is a link,
    then delete it.

    Otherwise sys.exit with an error message.

    :parameter path_src: source path
    :type path_src:  str

    :paramter path_dst: destination path
    :type path_dst:  str

    :parameter debug: whether we do nothing and just return a message
    :type debug:  bool

    :return: if debug=True then it returns a msg
    """

    from fabric.contrib.files import is_link
    from fabric.contrib.files import exists
    from fabric.operations import run

    cmd_rm = "rm {path_dst}".format(
        path_dst=path_dst
    )

    cmd_link = "ln -sf {path_src} {path_dst}".format(
        path_src=path_src,
        path_dst=path_dst
    )

    msg_debug = ""

    if exists(path_dst):
        if is_link(path_dst):
            if debug:
                msg_debug += "link already exists at dst, removing\n" \
                    "link_create:cmd_rm   : %s" % cmd_rm
            else:
                run(cmd_rm)
        else:
            msg_error = "something exists at dst - '%s' " \
                "- and it's not a link\n kicking out"

            sys.exit(msg_error.format(path_dst))

    if debug:
        msg_debug += "link_create:cmd_link : %s" % cmd_link
    else:
        run(cmd_link)

    return msg_debug


def prompt_continue(message="Do you want to continue? Y/n", default="Y",
                    exit=True):
    """
    prompts user if he wants to continue

    :parameter message: ask if user wants to continue
    :type message:  str

    :parameter default: the default entry that we expect for the user if he
        hits <enter> enter without giving a value
    :type default:  str

    :parameter exit: whether we do a sys.exit if it fails. default True
    :type exit:  bool
    """

    from fabric.operations import prompt

    prompt_val = prompt(message)

    if prompt_val == "":
        prompt_val = default

    if env.debug:
        printvar(
            "prompt_val", prompt_val,
            not booleanize(prompt_val))
        return True
    else:
        if not booleanize(prompt_val):
            if exit:
                sys.exit()
            else:
                return False


def check_debug(env):
    """
    helper method to determine if debug was set to True in the fabric
    environment

    :parameter env: the fabric environment
    :type env: dict

    :return: True if debug was set
    :rtype: bool
    """

    if hasattr(env, 'debug'):
        return env.debug
    else:
        return False