src/osmo_gsm_tester/util.py

# osmo_gsm_tester: language snippets
#
# Copyright (C) 2016-2017 by sysmocom - s.f.m.c. GmbH
#
# Author: Neels Hofmeyr <neels@hofmeyr.de>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import sys
import time
import fcntl
import hashlib
import tempfile
import shutil
import atexit
import threading
import importlib.util
import fcntl
import tty
import termios


class listdict:
    'a dict of lists { "a": [1, 2, 3],  "b": [1, 2] }'
    def __getattr__(ld, name):
        if name == 'add':
            return ld.__getattribute__(name)
        return ld.__dict__.__getattribute__(name)

    def add(ld, name, item):
        l = ld.__dict__.get(name)
        if not l:
            l = []
            ld.__dict__[name] = l
        l.append(item)
        return l

    def add_dict(ld, d):
        for k,v in d.items():
            ld.add(k, v)

    def __setitem__(ld, name, val):
        return ld.__dict__.__setitem__(name, val)

    def __getitem__(ld, name):
        return ld.__dict__.__getitem__(name)

    def __str__(ld):
        return ld.__dict__.__str__()


class DictProxy:
    '''
    allow accessing dict entries like object members
    syntactical sugar, adapted from http://stackoverflow.com/a/31569634
    so that e.g. templates can do ${bts.member} instead of ${bts['member']}
    '''
    def __init__(self, obj):
        self.obj = obj

    def __getitem__(self, key):
        return dict2obj(self.obj[key])

    def __getattr__(self, key):
        'provide error information to know which template item was missing'
        try:
            return dict2obj(getattr(self.obj, key))
        except AttributeError:
            try:
                return self[key]
            except KeyError:
                raise AttributeError(key)

def dict2obj(value):
    if is_list(value) or is_dict(value):
        return DictProxy(value)
    return value


class FileLock:
    def __init__(self, path, owner):
        self.path = path
        self.owner = owner
        self.f = None

    def __enter__(self):
        if self.f is not None:
            return
        self.fd = os.open(self.path, os.O_CREAT | os.O_WRONLY | os.O_TRUNC)
        fcntl.flock(self.fd, fcntl.LOCK_EX)
        os.truncate(self.fd, 0)
        os.write(self.fd, str(self.owner).encode('utf-8'))
        os.fsync(self.fd)

    def __exit__(self, *exc_info):
        #fcntl.flock(self.fd, fcntl.LOCK_UN)
        os.truncate(self.fd, 0)
        os.fsync(self.fd)
        os.close(self.fd)
        self.fd = -1

    def lock(self):
        self.__enter__()

    def unlock(self):
        self.__exit__()


class Dir():
    LOCK_FILE = 'lock'

    def __init__(self, path):
        self.path = path
        self.lock_path = os.path.join(self.path, Dir.LOCK_FILE)

    def lock(self, origin_id):
        '''
        return lock context, usage:

          with my_dir.lock(origin):
              read_from(my_dir.child('foo.txt'))
              write_to(my_dir.child('bar.txt'))
        '''
        self.mkdir()
        return FileLock(self.lock_path, origin_id)

    @staticmethod
    def ensure_abs_dir_exists(*path_elements):
        l = len(path_elements)
        if l < 1:
            raise RuntimeError('Cannot create empty path')
        if l == 1:
            path = path_elements[0]
        else:
            path = os.path.join(*path_elements)
        if not os.path.isdir(path):
            os.makedirs(path)

    def child(self, *rel_path):
        if not rel_path:
            return self.path
        return os.path.join(self.path, *rel_path)

    def mk_parentdir(self, *rel_path):
        child = self.child(*rel_path)
        child_parent = os.path.dirname(child)
        Dir.ensure_abs_dir_exists(child_parent)
        return child

    def mkdir(self, *rel_path):
        child = self.child(*rel_path)
        Dir.ensure_abs_dir_exists(child)
        return child

    def children(self):
        return os.listdir(self.path)

    def exists(self, *rel_path):
        return os.path.exists(self.child(*rel_path))

    def isdir(self, *rel_path):
        return os.path.isdir(self.child(*rel_path))

    def isfile(self, *rel_path):
        return os.path.isfile(self.child(*rel_path))

    def new_child(self, *rel_path):
        attempt = 1
        prefix, suffix = os.path.splitext(self.child(*rel_path))
        rel_path_fmt = '%s%%s%s' % (prefix, suffix)
        while True:
            path = rel_path_fmt % (('_%d'%attempt) if attempt > 1 else '')
            if not os.path.exists(path):
                break
            attempt += 1
            continue
        Dir.ensure_abs_dir_exists(os.path.dirname(path))
        return path

    def rel_path(self, path):
        return os.path.relpath(path, self.path)

    def touch(self, *rel_path):
        touch_file(self.child(*rel_path))

    def new_file(self, *rel_path):
        path = self.new_child(*rel_path)
        touch_file(path)
        return path

    def new_dir(self, *rel_path):
        path = self.new_child(*rel_path)
        Dir.ensure_abs_dir_exists(path)
        return path

    def __str__(self):
        return self.path
    def __repr__(self):
        return self.path

def touch_file(path):
    with open(path, 'a') as f:
        f.close()

def is_dict(l):
    return isinstance(l, dict)

def is_list(l):
    return isinstance(l, (list, tuple))


def dict_add(a, *b, **c):
    for bb in b:
        a.update(bb)
    a.update(c)
    return a

def _hash_recurse(acc, obj, ignore_keys):
    if is_dict(obj):
        for key, val in sorted(obj.items()):
            if key in ignore_keys:
                continue
            _hash_recurse(acc, val, ignore_keys)
        return

    if is_list(obj):
        for item in obj:
            _hash_recurse(acc, item, ignore_keys)
        return

    acc.update(str(obj).encode('utf-8'))

def hash_obj(obj, *ignore_keys):
    acc = hashlib.sha1()
    _hash_recurse(acc, obj, ignore_keys)
    return acc.hexdigest()


def md5(of_content):
    if isinstance(of_content, str):
        of_content = of_content.encode('utf-8')
    return hashlib.md5(of_content).hexdigest()

def md5_of_file(path):
    with open(path, 'rb') as f:
        return md5(f.read())

_tempdir = None

def get_tempdir(remove_on_exit=True):
    global _tempdir
    if _tempdir is not None:
        return _tempdir
    _tempdir = tempfile.mkdtemp()
    if remove_on_exit:
        atexit.register(lambda: shutil.rmtree(_tempdir))
    return _tempdir


if hasattr(importlib.util, 'module_from_spec'):
    def run_python_file(module_name, path):
        spec = importlib.util.spec_from_file_location(module_name, path)
        spec.loader.exec_module( importlib.util.module_from_spec(spec) )
else:
    from importlib.machinery import SourceFileLoader
    def run_python_file(module_name, path):
        SourceFileLoader(module_name, path).load_module()

def msisdn_inc(msisdn_str):
    'add 1 and preserve leading zeros'
    return ('%%0%dd' % len(msisdn_str)) % (int(msisdn_str) + 1)

class polling_stdin:
    def __init__(self, stream):
        self.stream = stream
        self.fd = self.stream.fileno()
    def __enter__(self):
        self.original_stty = termios.tcgetattr(self.stream)
        tty.setcbreak(self.stream)
        self.orig_fl = fcntl.fcntl(self.fd, fcntl.F_GETFL)
        fcntl.fcntl(self.fd, fcntl.F_SETFL, self.orig_fl | os.O_NONBLOCK)
    def __exit__(self, *args):
        fcntl.fcntl(self.fd, fcntl.F_SETFL, self.orig_fl)
        termios.tcsetattr(self.stream, termios.TCSANOW, self.original_stty)

def input_polling(poll_func, stream=None):
    if stream is None:
        stream = sys.stdin
    unbuffered_stdin = os.fdopen(stream.fileno(), 'rb', buffering=0)
    try:
        with polling_stdin(unbuffered_stdin):
            acc = []
            while True:
                poll_func()
                got = unbuffered_stdin.read(1)
                if got and len(got):
                    try:
                        # this is hacky: can't deal with multibyte sequences
                        got_str = got.decode('utf-8')
                    except:
                        got_str = '?'
                    acc.append(got_str)
                    sys.__stdout__.write(got_str)
                    sys.__stdout__.flush()
                    if '\n' in got_str:
                        return ''.join(acc)
                time.sleep(.1)
    finally:
        unbuffered_stdin.close()

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