platypush/platypush/utils/__init__.py
Fabio Manganiello c9a5c29a4a
🐛 A proper cross-version solution for the utcnow() issue.
No need to maintain two different pieces of logic - a `utcnow()` for
Python < 3.11 and `now(datetime.UTC)` for Python >= 3.11.

`datetime.timezone.utc` existed long before datetime.UTC and that's what
the `utcnow` facade should use.

This means that all the `utcnow()` will always have `tzinfo=UTC`
regardless of the Python version.

There's still a problem with the `utcnow()`-generated timestamps that
have been generated by previous versions of Python and stored on the db.

Therefore, when the code performs comparisons with timestamps fetched
from the db, it should always explicitly do a `.replace(tzinfo=utc)` to
ensure that we always compare offset-aware datetime representations.

See blog post for technical details:
https://manganiello.blog/wheres-my-time-again
2024-06-01 01:34:47 +02:00

825 lines
23 KiB
Python

import ast
import contextlib
import datetime
import functools
import hashlib
import importlib
import inspect
import logging
import os
import pathlib
import re
import signal
import socket
import ssl
import time
import urllib.request
from importlib.machinery import SourceFileLoader
from importlib.util import spec_from_loader, module_from_spec
from multiprocessing import Lock as PLock
from tempfile import gettempdir
from threading import Event, Lock as TLock
from typing import Generator, Optional, Tuple, Type, Union
from dateutil import parser, tz
from redis import Redis
from rsa.key import PublicKey, PrivateKey, newkeys
logger = logging.getLogger('utils')
Lock = Union[PLock, TLock] # type: ignore
def get_module_and_method_from_action(action):
"""
Input: action=music.mpd.play
Output: ('music.mpd', 'play')
"""
tokens = action.split('.')
module_name = str.join('.', tokens[:-1])
method_name = tokens[-1:][0]
return module_name, method_name
def get_message_class_by_type(msgtype):
"""Gets the class of a message type given as string"""
try:
module = importlib.import_module('platypush.message.' + msgtype)
except ImportError as e:
logger.warning('Unsupported message type %s', msgtype)
raise RuntimeError(e) from e
cls_name = msgtype[0].upper() + msgtype[1:]
try:
msgclass = getattr(module, cls_name)
except AttributeError as e:
logger.warning('No such class in %s: %s', module.__name__, cls_name)
raise RuntimeError(e) from e
return msgclass
def get_event_class_by_type(type): # pylint: disable=redefined-builtin
"""Gets an event class by type name"""
event_module = importlib.import_module('.'.join(type.split('.')[:-1]))
return getattr(event_module, type.split('.')[-1])
def get_plugin_module_by_name(plugin_name):
"""Gets the module of a plugin by name (e.g. "music.mpd" or "media.vlc")"""
module_name = 'platypush.plugins.' + plugin_name
try:
return importlib.import_module('platypush.plugins.' + plugin_name)
except ImportError as e:
logger.error('Cannot import %s: %s', module_name, e)
return None
def get_backend_module_by_name(backend_name):
"""Gets the module of a backend by name (e.g. "backend.http" or "backend.mqtt")"""
module_name = 'platypush.backend.' + backend_name
try:
return importlib.import_module('platypush.backend.' + backend_name)
except ImportError as e:
logger.error('Cannot import %s: %s', module_name, e)
return None
def get_plugin_class_by_name(plugin_name) -> Optional[type]:
"""Gets the class of a plugin by name (e.g. "music.mpd" or "media.vlc")"""
module = get_plugin_module_by_name(plugin_name)
if not module:
return None
class_name = getattr(
module, ''.join([_.capitalize() for _ in plugin_name.split('.')]) + 'Plugin'
)
try:
return getattr(
module, ''.join([_.capitalize() for _ in plugin_name.split('.')]) + 'Plugin'
)
except Exception as e:
logger.error('Cannot import class %s: %s', class_name, e)
return None
def get_plugin_name_by_class(plugin) -> str:
"""Gets the common name of a plugin (e.g. "music.mpd" or "media.vlc") given its class."""
from platypush.plugins import Plugin
if isinstance(plugin, Plugin):
plugin = plugin.__class__
class_name = plugin.__name__
class_tokens = [
token.lower()
for token in re.sub(r'([A-Z])', r' \1', class_name).split(' ')
if token.strip() and token != 'Plugin'
]
return '.'.join(class_tokens)
def get_backend_class_by_name(backend_name: str) -> Optional[type]:
"""Gets the class of a backend by name (e.g. "backend.http" or "backend.mqtt")"""
module = get_backend_module_by_name(backend_name)
if not module:
return None
class_name = getattr(
module,
''.join(
[
token.capitalize()
for i, token in enumerate(backend_name.split('.'))
if not (i == 0 and token == 'backend')
]
)
+ 'Backend',
)
try:
return getattr(
module,
''.join([_.capitalize() for _ in backend_name.split('.')]) + 'Backend',
)
except Exception as e:
logger.error('Cannot import class %s: %s', class_name, e)
return None
def get_backend_name_by_class(backend) -> str:
"""Gets the common name of a backend (e.g. "http" or "mqtt") given its class."""
from platypush.backend import Backend
if isinstance(backend, Backend):
backend = backend.__class__
class_name = backend.__name__
class_tokens = [
token.lower()
for token in re.sub(r'([A-Z])', r' \1', class_name).split(' ')
if token.strip() and token != 'Backend'
]
return '.'.join(class_tokens)
def set_timeout(seconds, on_timeout):
"""
Set a function to be called if timeout expires without being cleared.
It only works on the main thread.
Params:
seconds -- Timeout in seconds
on_timeout -- Function invoked on timeout unless clear_timeout is called before
"""
def _sighandler(*_):
on_timeout()
signal.signal(signal.SIGALRM, _sighandler)
signal.alarm(seconds)
def clear_timeout():
"""Clear any previously set timeout"""
signal.alarm(0)
def get_hash(s):
"""Get the SHA256 hash hex digest of a string input"""
return hashlib.sha256(s.encode('utf-8')).hexdigest()
def get_decorators(cls, climb_class_hierarchy=False):
"""
Get the decorators of a class as a {"decorator_name": [list of methods]} dictionary
:param cls: Class type
:param climb_class_hierarchy: If set to True (default: False), it will search return the decorators in the parent
classes as well
:type climb_class_hierarchy: bool
"""
decorators = {}
def visit_FunctionDef(node):
for n in node.decorator_list:
if isinstance(n, ast.Call):
name = (
n.func.attr
if isinstance(n.func, ast.Attribute)
else n.func.id # type: ignore
)
else:
name = n.attr if isinstance(n, ast.Attribute) else n.id
decorators[name] = decorators.get(name, set())
decorators[name].add(node.name)
if climb_class_hierarchy:
targets = inspect.getmro(cls)
else:
targets = [cls]
node_iter = ast.NodeVisitor()
node_iter.visit_FunctionDef = visit_FunctionDef
for target in targets:
with contextlib.suppress(TypeError):
node_iter.visit(ast.parse(inspect.getsource(target)))
return decorators
def get_redis_queue_name_by_message(msg) -> Optional[str]:
"""
Get the Redis queue name for the response(s) associated to a request
message.
:param msg: Input message, as a :class:`platypush.message.request.Request`
object.
"""
from platypush.message.request import Request
if not isinstance(msg, Request):
logger.warning('Not a valid request (type: %s): %s', type(msg), msg)
return None
return f'platypush/responses/{msg.id}' if msg.id else None
def _get_ssl_context(
context_type=None, ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None
):
if not context_type:
ssl_context = ssl.create_default_context(cafile=ssl_cafile, capath=ssl_capath)
else:
ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
assert ssl_cert, 'No certificate specified'
if ssl_cafile or ssl_capath:
ssl_context.load_verify_locations(cafile=ssl_cafile, capath=ssl_capath)
ssl_context.load_cert_chain(
certfile=os.path.abspath(os.path.expanduser(ssl_cert)),
keyfile=os.path.abspath(os.path.expanduser(ssl_key)) if ssl_key else None,
)
return ssl_context
def get_ssl_context(ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None):
"""
Generic builder for SSL context.
"""
return _get_ssl_context(
context_type=None,
ssl_cert=ssl_cert,
ssl_key=ssl_key,
ssl_cafile=ssl_cafile,
ssl_capath=ssl_capath,
)
def get_ssl_server_context(
ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None
):
"""
Builder for a server-side SSL context.
"""
return _get_ssl_context(
context_type=ssl.PROTOCOL_TLS_SERVER,
ssl_cert=ssl_cert,
ssl_key=ssl_key,
ssl_cafile=ssl_cafile,
ssl_capath=ssl_capath,
)
def get_ssl_client_context(
ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None
):
"""
Builder for a client-side SSL context.
"""
return _get_ssl_context(
context_type=ssl.PROTOCOL_TLS_CLIENT,
ssl_cert=ssl_cert,
ssl_key=ssl_key,
ssl_cafile=ssl_cafile,
ssl_capath=ssl_capath,
)
def find_bins_in_path(bin_name):
"""
Search for a binary in the PATH variable.
"""
return [
os.path.join(p, bin_name)
for p in os.environ.get('PATH', '').split(':')
if os.path.isfile(os.path.join(p, bin_name))
and (os.name == 'nt' or os.access(os.path.join(p, bin_name), os.X_OK))
]
def find_files_by_ext(directory, *exts):
"""
Finds all the files in the given directory with the provided extensions.
"""
if not exts:
raise AttributeError('No extensions provided')
if not os.path.isdir(directory):
raise AttributeError(f'{directory} is not a valid directory')
min_len = len(min(exts, key=len))
max_len = len(max(exts, key=len))
result = []
for _, __, files in os.walk(directory):
for i in range(min_len, max_len + 1):
result += [f for f in files if f[-i:] in exts]
return result
def is_process_alive(pid: int) -> bool:
"""
:param pid: Process ID.
:return: True if the process with the given PID is alive.
"""
try:
os.kill(pid, 0)
return True
except OSError:
return False
def get_ip_or_hostname() -> str:
"""
Get the the default IP address or hostname of the machine.
"""
ip = socket.gethostbyname(socket.gethostname())
if ip.startswith('127.') or ip.startswith('::1'):
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.connect(('10.255.255.255', 1))
ip = sock.getsockname()[0]
sock.close()
except Exception as e:
logger.debug(e)
return ip
def get_mime_type(resource: str) -> Optional[str]:
"""
Get the MIME type of the given resource.
:param resource: The resource to get the MIME type for - it can be a file
path or a URL.
"""
import magic
if resource.startswith('file://'):
offset = len('file://')
resource = resource[offset:]
if resource.startswith('http://') or resource.startswith('https://'):
with urllib.request.urlopen(resource) as response:
return response.info().get_content_type()
else:
if hasattr(magic, 'detect_from_filename'):
mime = magic.detect_from_filename(resource) # type: ignore
elif hasattr(magic, 'from_file'):
mime = magic.from_file(resource, mime=True)
else:
raise RuntimeError(
'The installed magic version provides neither detect_from_filename nor from_file'
)
if mime:
return mime.mime_type if hasattr(mime, 'mime_type') else mime # type: ignore
return None
def camel_case_to_snake_case(string):
"""
Utility function to convert CamelCase to snake_case.
"""
s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', string)
return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
def grouper(n, iterable, fillvalue=None):
"""
Split an iterable in groups of max N elements.
grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx
"""
from itertools import zip_longest
args = [iter(iterable)] * n
if fillvalue:
return zip_longest(*args, fillvalue=fillvalue)
for chunk in zip_longest(*args):
yield filter(None, chunk)
return
def is_functional_procedure(obj) -> bool:
"""
Check if the given object is a functional procedure.
"""
return callable(obj) and hasattr(obj, 'procedure')
def is_functional_hook(obj) -> bool:
"""
Check if the given object is a functional hook.
"""
return callable(obj) and hasattr(obj, 'hook')
def is_functional_cron(obj) -> bool:
"""
Check if the given object is a functional cron.
"""
return callable(obj) and hasattr(obj, 'cron') and hasattr(obj, 'cron_expression')
def run(action, *args, **kwargs):
"""
Run the given action with the given arguments. Example:
>>> from platypush.utils import run
>>> run('music.mpd.play', resource='file:///home/user/music.mp3')
"""
from platypush.config import Config
from platypush.context import get_plugin
from platypush.procedure import Procedure
if action.startswith('procedure.'):
procedure_name = action.removeprefix('procedure.')
procedures = Config.get_procedures()
procedure = procedures.get(procedure_name)
if not procedure:
raise RuntimeError(f'No such procedure: {procedure_name}')
if isinstance(procedure, dict):
procedure = Procedure.build(
name=procedure_name,
requests=procedure.get('actions', []),
args=procedure.get('args', {}),
_async=procedure.get('async', False),
)
return procedure.execute(*args, **kwargs)
return procedure(*args, **kwargs)
(module_name, method_name) = get_module_and_method_from_action(action)
plugin = get_plugin(module_name)
method = getattr(plugin, method_name)
response = method(*args, **kwargs)
if response.errors:
raise RuntimeError(response.errors[0])
return response.output
def generate_rsa_key_pair(
key_file: Optional[str] = None, size: int = 2048
) -> Tuple[PublicKey, PrivateKey]:
"""
Generate an RSA key pair.
:param key_file: Target file for the private key (the associated public key will be stored in ``<key_file>.pub``.
If no key file is specified then the public and private keys will be returned in ASCII format in a dictionary
with the following structure:
.. code-block:: json
{
"private": "private key here",
"public": "public key here"
}
:param size: Key size (default: 2048 bits).
:return: A tuple with the generated ``(priv_key_str, pub_key_str)``.
"""
logger.info('Generating RSA keypair')
pub_key, priv_key = newkeys(size)
logger.info('Generated RSA keypair')
public_key_str = pub_key.save_pkcs1('PEM').decode()
private_key_str = priv_key.save_pkcs1('PEM').decode()
if key_file:
logger.info('Saving private key to %s', key_file)
with open(os.path.expanduser(key_file), 'w') as f1, open(
os.path.expanduser(key_file) + '.pub', 'w'
) as f2:
f1.write(private_key_str)
f2.write(public_key_str)
os.chmod(key_file, 0o600)
return pub_key, priv_key
def get_or_generate_jwt_rsa_key_pair():
"""
Get or generate a JWT RSA key pair.
"""
from platypush.config import Config
key_dir = os.path.join(Config.get_workdir(), 'jwt')
priv_key_file = os.path.join(key_dir, 'id_rsa')
pub_key_file = priv_key_file + '.pub'
if os.path.isfile(priv_key_file) and os.path.isfile(pub_key_file):
with open(pub_key_file, 'r') as f1, open(priv_key_file, 'r') as f2:
return (
PublicKey.load_pkcs1(f1.read().encode()),
PrivateKey.load_pkcs1(f2.read().encode()),
)
pathlib.Path(key_dir).mkdir(parents=True, exist_ok=True, mode=0o755)
return generate_rsa_key_pair(priv_key_file, size=2048)
def get_enabled_plugins() -> dict:
"""
Get the enabled plugins.
:return: A dictionary with the enabled plugins, in the format ``name`` ->
:class:`platypush.plugins.Plugin` instance.
"""
from platypush.config import Config
from platypush.context import get_plugin
plugins = {}
for name in Config.get_plugins():
try:
plugin = get_plugin(name)
if plugin:
plugins[name] = plugin
except Exception as e:
logger.warning('Could not initialize plugin %s', name)
logger.exception(e)
return plugins
def get_enabled_backends() -> dict:
"""
Get the enabled backends.
:return: A dictionary with the enabled backends, in the format ``name`` ->
:class:`platypush.backend.Backend` instance.
"""
from platypush.config import Config
from platypush.context import get_backend
backends = {}
for name in Config.get_backends():
try:
backend = get_backend(name.removeprefix('backend.'))
if backend:
backends[name] = backend
except Exception as e:
logger.warning('Could not initialize backend %s', name)
logger.exception(e)
return backends
def get_redis_conf() -> dict:
"""
Get the Redis connection arguments from the configuration.
"""
from platypush.config import Config
return (
Config.get('redis')
or (Config.get('backend.redis') or {}).get('redis_args', {})
or {}
)
def get_redis(*args, **kwargs) -> Redis:
"""
Get a Redis client on the basis of the Redis configuration.
The Redis configuration can be loaded from:
1. The ``redis`` plugin.
2. The ``backend.redis`` configuration (``redis_args`` attribute)
"""
if not (args or kwargs):
kwargs = get_redis_conf()
return Redis(*args, **kwargs)
def to_datetime(t: Union[str, int, float, datetime.datetime]) -> datetime.datetime:
"""
Utility function to convert a datetime/timestamp provided as a
string/integer/float/datetime to a ``datetime.datetime`` instance.
"""
if isinstance(t, (int, float)):
return datetime.datetime.fromtimestamp(t, tz=tz.tzutc())
if isinstance(t, str):
return parser.parse(t)
return t
@contextlib.contextmanager
def get_lock(
lock: Lock, timeout: Optional[float] = None
) -> Generator[bool, None, None]:
"""
Get a lock with an optional timeout through a context manager construct:
>>> from threading import Lock
>>> lock = Lock()
>>> with get_lock(lock, timeout=2):
>>> ...
"""
kwargs = {'timeout': timeout} if timeout else {}
result = lock.acquire(**kwargs)
try:
if not result:
raise TimeoutError()
yield result
finally:
if result:
lock.release()
def get_default_pid_file() -> str:
"""
Get the default PID file path.
"""
return os.path.join(gettempdir(), 'platypush.pid')
def get_remaining_timeout(
timeout: Optional[float], start: float, cls: Union[Type[int], Type[float]] = float
) -> Optional[Union[int, float]]:
"""
Get the remaining timeout, given a start time.
"""
if timeout is None:
return None
return cls(max(0, timeout - (time.time() - start)))
def get_src_root() -> str:
"""
:return: The root source folder of the application.
"""
import platypush
return os.path.dirname(inspect.getfile(platypush))
def is_root() -> bool:
"""
:return: True if the current user is root/administrator.
"""
return os.getuid() == 0
def get_message_response(msg):
"""
Get the response to the given message.
:param msg: The message to get the response for.
:return: The response to the given message.
"""
from platypush.message import Message
redis = get_redis()
redis_queue = get_redis_queue_name_by_message(msg)
if not redis_queue:
return None
response = redis.blpop(redis_queue, timeout=60)
if response and len(response) > 1:
response = Message.build(response[1])
else:
response = None
return response
def import_file(path: str, name: Optional[str] = None):
"""
Import a Python file as a module, even if no __init__.py is
defined in the directory.
:param path: Path of the file to import.
:param name: Custom name for the imported module (default: same as the file's basename).
:return: The imported module.
"""
name = name or re.split(r"\.py$", os.path.basename(path))[0]
loader = SourceFileLoader(name, os.path.expanduser(path))
mod_spec = spec_from_loader(name, loader)
assert mod_spec, f"Cannot create module specification for {path}"
mod = module_from_spec(mod_spec)
loader.exec_module(mod)
return mod
def get_defining_class(meth) -> Optional[type]:
"""
See https://stackoverflow.com/a/25959545/622364.
This is the best way I could find of answering the question "given a bound
method, get the class that defined it",
"""
if isinstance(meth, type):
return meth
if isinstance(meth, functools.partial):
return get_defining_class(meth.func)
if inspect.ismethod(meth) or (
inspect.isbuiltin(meth)
and getattr(meth, '__self__', None) is not None
and getattr(meth.__self__, '__class__', None)
):
for cls in inspect.getmro(meth.__self__.__class__):
if meth.__name__ in cls.__dict__:
return cls
meth = getattr(meth, '__func__', meth) # fallback to __qualname__ parsing
if inspect.isfunction(meth):
cls = getattr(
inspect.getmodule(meth),
meth.__qualname__.split('.<locals>', 1)[0].rsplit('.', 1)[0],
None,
)
if isinstance(cls, type):
return cls
return getattr(meth, '__objclass__', None) # handle special descriptor objects
def is_debug_enabled() -> bool:
"""
:return: True if the debug mode is enabled.
"""
from platypush.config import Config
return (Config.get('logging') or {}).get('level') == logging.DEBUG
def get_default_downloads_dir() -> str:
"""
:return: The default downloads directory.
"""
return os.path.join(os.path.expanduser('~'), 'Downloads')
def wait_for_either(*events, timeout: Optional[float] = None, cls: Type = Event):
"""
Wait for any of the given events to be set.
:param events: The events to be checked.
:param timeout: The maximum time to wait for the event to be set. Default: None.
:param cls: The class to be used for the event. Default: threading.Event.
"""
from .threads import OrEvent
return OrEvent(*events, cls=cls).wait(timeout=timeout)
def utcnow():
"""
utcnow() without tears. It always returns a datetime object in UTC
timezone.
"""
return datetime.datetime.now(datetime.timezone.utc)
# vim:sw=4:ts=4:et: