[enh] replace requests by httpx

searx/poolrequests.py

@@ -1,14 +1,54 @@
+import atexit
 import sys
+import threading
+import asyncio
+import logging
+import concurrent.futures
 from time import time
 from itertools import cycle
-from threading import local
 
-import requests
+import httpcore
+import httpx
+import h2.exceptions
+from httpx_socks import AsyncProxyTransport
+from python_socks import parse_proxy_url
+import python_socks._errors
 
 from searx import settings
 from searx import logger
 from searx.raise_for_httperror import raise_for_httperror
 
+# Optional uvloop (support Python 3.6)
+try:
+    import uvloop
+except ImportError:
+    pass
+else:
+    uvloop.install()
+
+# queue.SimpleQueue: Support Python 3.6
+try:
+    from queue import SimpleQueue
+except ImportError:
+    from queue import Empty
+    from collections import deque
+
+    class SimpleQueue:
+        """Minimal backport of queue.SimpleQueue"""
+
+        def __init__(self):
+            self._queue = deque()
+            self._count = threading.Semaphore(0)
+
+        def put(self, item):
+            self._queue.append(item)
+            self._count.release()
+
+        def get(self, timeout=None):
+            if not self._count.acquire(True, timeout):
+                raise Empty
+            return self._queue.popleft()
+
 
 logger = logger.getChild('poolrequests')
 
@@ -31,99 +71,63 @@ if not getattr(ssl, "HAS_SNI", False):
         sys.exit(1)
 
 
-class HTTPAdapterWithConnParams(requests.adapters.HTTPAdapter):
-
-    def __init__(self, pool_connections=requests.adapters.DEFAULT_POOLSIZE,
-                 pool_maxsize=requests.adapters.DEFAULT_POOLSIZE,
-                 max_retries=requests.adapters.DEFAULT_RETRIES,
-                 pool_block=requests.adapters.DEFAULT_POOLBLOCK,
-                 **conn_params):
-        if max_retries == requests.adapters.DEFAULT_RETRIES:
-            self.max_retries = requests.adapters.Retry(0, read=False)
-        else:
-            self.max_retries = requests.adapters.Retry.from_int(max_retries)
-        self.config = {}
-        self.proxy_manager = {}
-
-        super().__init__()
-
-        self._pool_connections = pool_connections
-        self._pool_maxsize = pool_maxsize
-        self._pool_block = pool_block
-        self._conn_params = conn_params
-
-        self.init_poolmanager(pool_connections, pool_maxsize, block=pool_block, **conn_params)
-
-    def __setstate__(self, state):
-        # Can't handle by adding 'proxy_manager' to self.__attrs__ because
-        # because self.poolmanager uses a lambda function, which isn't pickleable.
-        self.proxy_manager = {}
-        self.config = {}
-
-        for attr, value in state.items():
-            setattr(self, attr, value)
-
-        self.init_poolmanager(self._pool_connections, self._pool_maxsize,
-                              block=self._pool_block, **self._conn_params)
+LOOP = None
+CLIENTS = dict()
+THREADLOCAL = threading.local()
+LIMITS = httpx.Limits(
+    # Magic number kept from previous code
+    max_connections=settings['outgoing'].get('pool_connections', 100),
+    # Picked from constructor
+    max_keepalive_connections=settings['outgoing'].get('pool_maxsize', 10),
+    #
+    keepalive_expiry=settings['outgoing'].get('keepalive_expiry', 5.0)
+)
+# default parameters for AsyncHTTPTransport
+# see https://github.com/encode/httpx/blob/e05a5372eb6172287458b37447c30f650047e1b8/httpx/_transports/default.py#L108-L121  # noqa
+TRANSPORT_KWARGS = {
+    'http2': settings['outgoing'].get('http2', False),
+    'retries': 0,
+    'trust_env': False,
+    'backend': 'asyncio'
+}
+# requests compatibility when reading proxy settings from settings.yml
+PROXY_PATTERN_MAPPING = {
+    'http': 'https://',
+    'https:': 'https://'
+}
+# default maximum redirect
+# from https://github.com/psf/requests/blob/8c211a96cdbe9fe320d63d9e1ae15c5c07e179f8/requests/models.py#L55
+DEFAULT_REDIRECT_LIMIT = 30
 
 
-threadLocal = local()
-connect = settings['outgoing'].get('pool_connections', 100)  # Magic number kept from previous code
-maxsize = settings['outgoing'].get('pool_maxsize', requests.adapters.DEFAULT_POOLSIZE)  # Picked from constructor
 if settings['outgoing'].get('source_ips'):
-    http_adapters = cycle(HTTPAdapterWithConnParams(pool_connections=connect, pool_maxsize=maxsize,
-                                                    source_address=(source_ip, 0))
-                          for source_ip in settings['outgoing']['source_ips'])
-    https_adapters = cycle(HTTPAdapterWithConnParams(pool_connections=connect, pool_maxsize=maxsize,
-                                                     source_address=(source_ip, 0))
-                           for source_ip in settings['outgoing']['source_ips'])
+    LOCAL_ADDRESS_CYCLE = cycle(settings['outgoing'].get('source_ips'))
 else:
-    http_adapters = cycle((HTTPAdapterWithConnParams(pool_connections=connect, pool_maxsize=maxsize), ))
-    https_adapters = cycle((HTTPAdapterWithConnParams(pool_connections=connect, pool_maxsize=maxsize), ))
-
-
-class SessionSinglePool(requests.Session):
-
-    def __init__(self):
-        super().__init__()
-
-        # reuse the same adapters
-        self.adapters.clear()
-
-        https_adapter = threadLocal.__dict__.setdefault('https_adapter', next(https_adapters))
-        self.mount('https://', https_adapter)
-        if get_enable_http_protocol():
-            http_adapter = threadLocal.__dict__.setdefault('http_adapter', next(http_adapters))
-            self.mount('http://', http_adapter)
-
-    def close(self):
-        """Call super, but clear adapters since there are managed globaly"""
-        self.adapters.clear()
-        super().close()
+    LOCAL_ADDRESS_CYCLE = cycle((None, ))
 
 
 def set_timeout_for_thread(timeout, start_time=None):
-    threadLocal.timeout = timeout
-    threadLocal.start_time = start_time
+    THREADLOCAL.timeout = timeout
+    THREADLOCAL.start_time = start_time
 
 
 def set_enable_http_protocol(enable_http):
-    threadLocal.enable_http = enable_http
+    THREADLOCAL.enable_http = enable_http
 
 
 def get_enable_http_protocol():
     try:
-        return threadLocal.enable_http
+        return THREADLOCAL.enable_http
     except AttributeError:
         return False
 
 
 def reset_time_for_thread():
-    threadLocal.total_time = 0
+    THREADLOCAL.total_time = 0
 
 
 def get_time_for_thread():
-    return threadLocal.total_time
+    return THREADLOCAL.total_time
 
 
 def get_proxy_cycles(proxy_settings):
@@ -152,22 +156,197 @@ def get_global_proxies():
     return get_proxies(GLOBAL_PROXY_CYCLES)
 
 
+async def close_connections_for_url(connection_pool: httpcore.AsyncConnectionPool, url: httpcore._utils.URL):
+    origin = httpcore._utils.url_to_origin(url)
+    logger.debug('Drop connections for %r', origin)
+    connections_to_close = connection_pool._connections_for_origin(origin)
+    for connection in connections_to_close:
+        await connection_pool._remove_from_pool(connection)
+        try:
+            await connection.aclose()
+        except httpcore.NetworkError as e:
+            logger.warning('Error closing an existing connection', exc_info=e)
+
+
+class AsyncHTTPTransportNoHttp(httpcore.AsyncHTTPTransport):
+    """Block HTTP request"""
+
+    async def arequest(self, method, url, headers=None, stream=None, ext=None):
+        raise httpcore.UnsupportedProtocol("HTTP protocol is disabled")
+
+
+class AsyncProxyTransportFixed(AsyncProxyTransport):
+    """Fix httpx_socks.AsyncProxyTransport
+
+    Map python_socks exceptions to httpcore.ProxyError
+
+    Map socket.gaierror to httpcore.ConnectError
+
+    Note: keepalive_expiry is ignored, AsyncProxyTransport should call:
+    * self._keepalive_sweep()
+    * self._response_closed(self, connection)
+
+    Note: AsyncProxyTransport inherit from AsyncConnectionPool
+
+    Note: the API is going to change on httpx 0.18.0
+    see https://github.com/encode/httpx/pull/1522
+    """
+
+    async def arequest(self, method, url, headers=None, stream=None, ext=None):
+        retry = 2
+        while retry > 0:
+            retry -= 1
+            try:
+                return await super().arequest(method, url, headers, stream, ext)
+            except (python_socks._errors.ProxyConnectionError,
+                    python_socks._errors.ProxyTimeoutError,
+                    python_socks._errors.ProxyError) as e:
+                raise httpcore.ProxyError(e)
+            except OSError as e:
+                # socket.gaierror when DNS resolution fails
+                raise httpcore.NetworkError(e)
+            except httpcore.RemoteProtocolError as e:
+                # in case of httpcore.RemoteProtocolError: Server disconnected
+                await close_connections_for_url(self, url)
+                logger.warning('httpcore.RemoteProtocolError: retry', exc_info=e)
+                # retry
+            except (httpcore.NetworkError, httpcore.ProtocolError) as e:
+                # httpcore.WriteError on HTTP/2 connection leaves a new opened stream
+                # then each new request creates a new stream and raise the same WriteError
+                await close_connections_for_url(self, url)
+                raise e
+
+
+class AsyncHTTPTransportFixed(httpx.AsyncHTTPTransport):
+    """Fix httpx.AsyncHTTPTransport"""
+
+    async def arequest(self, method, url, headers=None, stream=None, ext=None):
+        retry = 2
+        while retry > 0:
+            retry -= 1
+            try:
+                return await super().arequest(method, url, headers, stream, ext)
+            except OSError as e:
+                # socket.gaierror when DNS resolution fails
+                raise httpcore.ConnectError(e)
+            except httpcore.CloseError as e:
+                # httpcore.CloseError: [Errno 104] Connection reset by peer
+                # raised by _keepalive_sweep()
+                #   from https://github.com/encode/httpcore/blob/4b662b5c42378a61e54d673b4c949420102379f5/httpcore/_backends/asyncio.py#L198  # noqa
+                await close_connections_for_url(self._pool, url)
+                logger.warning('httpcore.CloseError: retry', exc_info=e)
+                # retry
+            except httpcore.RemoteProtocolError as e:
+                # in case of httpcore.RemoteProtocolError: Server disconnected
+                await close_connections_for_url(self._pool, url)
+                logger.warning('httpcore.RemoteProtocolError: retry', exc_info=e)
+                # retry
+            except (httpcore.ProtocolError, httpcore.NetworkError) as e:
+                await close_connections_for_url(self._pool, url)
+                raise e
+
+
+def get_transport_for_socks_proxy(verify, local_address, proxy_url):
+    global LOOP, LIMITS, TRANSPORT_KWARGS
+    # support socks5h (requests compatibility):
+    # https://requests.readthedocs.io/en/master/user/advanced/#socks
+    # socks5://   hostname is resolved on client side
+    # socks5h://  hostname is resolved on proxy side
+    rdns = False
+    socks5h = 'socks5h://'
+    if proxy_url.startswith(socks5h):
+        proxy_url = 'socks5://' + proxy_url[len(socks5h):]
+        rdns = True
+
+    proxy_type, proxy_host, proxy_port, proxy_username, proxy_password = parse_proxy_url(proxy_url)
+
+    return AsyncProxyTransportFixed(proxy_type=proxy_type, proxy_host=proxy_host, proxy_port=proxy_port,
+                                    username=proxy_username, password=proxy_password,
+                                    rdns=rdns,
+                                    loop=LOOP,
+                                    verify=verify,
+                                    local_address=local_address,
+                                    max_connections=LIMITS.max_connections,
+                                    max_keepalive_connections=LIMITS.max_keepalive_connections,
+                                    keepalive_expiry=LIMITS.keepalive_expiry,
+                                    **TRANSPORT_KWARGS)
+
+
+def get_transport(verify, local_address, proxy_url):
+    global LIMITS
+    return AsyncHTTPTransportFixed(verify=verify,
+                                   local_address=local_address,
+                                   limits=LIMITS,
+                                   proxy=httpx._config.Proxy(proxy_url) if proxy_url else None,
+                                   **TRANSPORT_KWARGS)
+
+
+def iter_proxies(proxies):
+    # https://www.python-httpx.org/compatibility/#proxy-keys
+    if isinstance(proxies, str):
+        yield 'all://', proxies
+    elif isinstance(proxies, dict):
+        for pattern, proxy_url in proxies.items():
+            pattern = PROXY_PATTERN_MAPPING.get(pattern, pattern)
+            yield pattern, proxy_url
+
+
+def new_client(verify, local_address, proxies, max_redirects, enable_http):
+    # See https://www.python-httpx.org/advanced/#routing
+    mounts = {}
+    for pattern, proxy_url in iter_proxies(proxies):
+        if not enable_http and (pattern == 'http' or pattern.startswith('http://')):
+            continue
+        if proxy_url.startswith('socks4://') \
+           or proxy_url.startswith('socks5://') \
+           or proxy_url.startswith('socks5h://'):
+            mounts[pattern] = get_transport_for_socks_proxy(verify, local_address, proxy_url)
+        else:
+            mounts[pattern] = get_transport(verify, local_address, proxy_url)
+
+    if not enable_http:
+        mounts['http://'] = AsyncHTTPTransportNoHttp()
+
+    transport = get_transport(verify, local_address, None)
+    return httpx.AsyncClient(transport=transport, mounts=mounts, max_redirects=max_redirects)
+
+
+def get_client(verify, local_address, proxies, max_redirects, allow_http):
+    global CLIENTS
+    key = (verify, local_address, repr(proxies), max_redirects, allow_http)
+    if key not in CLIENTS:
+        CLIENTS[key] = new_client(verify, local_address, proxies, max_redirects, allow_http)
+    return CLIENTS[key]
+
+
+async def send_request(method, url, enable_http, kwargs):
+    if isinstance(url, bytes):
+        url = url.decode()
+
+    verify = kwargs.pop('verify', True)
+    local_address = next(LOCAL_ADDRESS_CYCLE)
+    proxies = kwargs.pop('proxies', None) or get_global_proxies()
+    max_redirects = kwargs.pop('max_redirects', DEFAULT_REDIRECT_LIMIT)
+
+    client = get_client(verify, local_address, proxies, max_redirects, enable_http)
+    response = await client.request(method.upper(), url, **kwargs)
+
+    # requests compatibility
+    # see also https://www.python-httpx.org/compatibility/#checking-for-4xx5xx-responses
+    response.ok = not response.is_error
+
+    return response
+
+
 def request(method, url, **kwargs):
     """same as requests/requests/api.py request(...)"""
     time_before_request = time()
 
-    # session start
-    session = SessionSinglePool()
-
-    # proxies
-    if not kwargs.get('proxies'):
-        kwargs['proxies'] = get_global_proxies()
-
     # timeout
     if 'timeout' in kwargs:
         timeout = kwargs['timeout']
     else:
-        timeout = getattr(threadLocal, 'timeout', None)
+        timeout = getattr(THREADLOCAL, 'timeout', None)
         if timeout is not None:
             kwargs['timeout'] = timeout
 
@@ -178,24 +357,23 @@ def request(method, url, **kwargs):
         del kwargs['raise_for_httperror']
 
     # do request
-    response = session.request(method=method, url=url, **kwargs)
+    future = asyncio.run_coroutine_threadsafe(send_request(method, url, get_enable_http_protocol(), kwargs), LOOP)
+    try:
+        if timeout:
+            timeout += 0.2  # overhead
+            start_time = getattr(THREADLOCAL, 'start_time', time_before_request)
+            if start_time:
+                timeout -= time() - start_time
 
-    time_after_request = time()
+        response = future.result(timeout or 120)
+    except concurrent.futures.TimeoutError as e:
+        raise httpx.TimeoutException('Timeout', request=None) from e
 
-    # is there a timeout for this engine ?
-    if timeout is not None:
-        timeout_overhead = 0.2  # seconds
-        # start_time = when the user request started
-        start_time = getattr(threadLocal, 'start_time', time_before_request)
-        search_duration = time_after_request - start_time
-        if search_duration > timeout + timeout_overhead:
-            raise requests.exceptions.Timeout(response=response)
-
-    # session end
-    session.close()
-
-    if hasattr(threadLocal, 'total_time'):
-        threadLocal.total_time += time_after_request - time_before_request
+    # update total_time.
+    # See get_time_for_thread() and reset_time_for_thread()
+    if hasattr(THREADLOCAL, 'total_time'):
+        time_after_request = time()
+        THREADLOCAL.total_time += time_after_request - time_before_request
 
     # raise an exception
     if check_for_httperror:
@@ -204,6 +382,49 @@ def request(method, url, **kwargs):
     return response
 
 
+async def stream_chunk_to_queue(method, url, q, **kwargs):
+    verify = kwargs.pop('verify', True)
+    local_address = next(LOCAL_ADDRESS_CYCLE)
+    proxies = kwargs.pop('proxies', None) or get_global_proxies()
+    # "30" from requests:
+    # https://github.com/psf/requests/blob/8c211a96cdbe9fe320d63d9e1ae15c5c07e179f8/requests/models.py#L55
+    max_redirects = kwargs.pop('max_redirects', 30)
+    client = get_client(verify, local_address, proxies, max_redirects, True)
+    try:
+        async with client.stream(method, url, **kwargs) as response:
+            q.put(response)
+            async for chunk in response.aiter_bytes(65536):
+                if len(chunk) > 0:
+                    q.put(chunk)
+    except (httpx.HTTPError, OSError, h2.exceptions.ProtocolError) as e:
+        q.put(e)
+    finally:
+        q.put(None)
+
+
+def stream(method, url, **kwargs):
+    """Replace httpx.stream.
+
+    Usage:
+    stream = poolrequests.stream(...)
+    response = next(stream)
+    for chunk in stream:
+        ...
+
+    httpx.Client.stream requires to write the httpx.HTTPTransport version of the
+    the httpx.AsyncHTTPTransport declared above.
+    """
+    q = SimpleQueue()
+    future = asyncio.run_coroutine_threadsafe(stream_chunk_to_queue(method, url, q, **kwargs), LOOP)
+    chunk_or_exception = q.get(timeout=60)
+    while chunk_or_exception is not None:
+        if isinstance(chunk_or_exception, Exception):
+            raise chunk_or_exception
+        yield chunk_or_exception
+        chunk_or_exception = q.get(timeout=60)
+    return future.result()
+
+
 def get(url, **kwargs):
     kwargs.setdefault('allow_redirects', True)
     return request('get', url, **kwargs)
@@ -233,3 +454,97 @@ def patch(url, data=None, **kwargs):
 
 def delete(url, **kwargs):
     return request('delete', url, **kwargs)
+
+
+def init():
+    # log
+    for logger_name in ('hpack.hpack', 'hpack.table'):
+        logging.getLogger(logger_name).setLevel(logging.WARNING)
+
+    # loop
+    def loop_thread():
+        global LOOP
+        LOOP = asyncio.new_event_loop()
+        LOOP.run_forever()
+
+    th = threading.Thread(
+        target=loop_thread,
+        name='asyncio_loop',
+        daemon=True,
+    )
+    th.start()
+
+
+@atexit.register
+def done():
+    """Close all HTTP client
+
+    Avoid a warning at exit
+    see https://github.com/encode/httpx/blob/1a6e254f72d9fd5694a1c10a28927e193ab4f76b/httpx/_client.py#L1785
+    """
+    global LOOP
+
+    async def close_client(client):
+        try:
+            await client.aclose()
+        except httpx.HTTPError:
+            pass
+
+    async def close_clients():
+        await asyncio.gather(*[close_client(client) for client in CLIENTS.values()], return_exceptions=False)
+    future = asyncio.run_coroutine_threadsafe(close_clients(), LOOP)
+    # wait 3 seconds to close the HTTP clients
+    future.result(3)
+
+
+init()
+
+
+# ## TEMPORARY DEBUG ##
+
+
+def debug_connection(connection):
+    now = LOOP.time()
+    expired = (connection.state == httpcore._async.base.ConnectionState.IDLE
+               and connection.expires_at is not None
+               and now >= connection.expires_at)
+    return connection.info()\
+        + (', connect_failed' if connection.connect_failed else '')\
+        + (', expired' if expired else '')
+
+
+def debug_origin(origin):
+    return origin[0].decode() + '://' + origin[1].decode() + ':' + str(origin[2])
+
+
+def debug_transport(transport):
+    result = {
+        '__class__': str(transport.__class__.__name__)
+    }
+    if isinstance(transport, (httpx.AsyncHTTPTransport, AsyncHTTPTransportFixed)):
+        pool = transport._pool
+        result['__pool_class__'] = str(pool.__class__.__name__)
+        if isinstance(pool, httpcore.AsyncConnectionPool):
+            for origin, connections in pool._connections.items():
+                result[debug_origin(origin)] = [debug_connection(connection) for connection in connections]
+            return result
+    elif isinstance(transport, AsyncProxyTransportFixed):
+        for origin, connections in transport._connections.items():
+            result[debug_origin(origin)] = [debug_connection(connection) for connection in connections]
+        return result
+    return result
+
+
+def debug_asyncclient(client, key=None):
+    result = {}
+    if key:
+        result['__key__'] = [k if isinstance(k, (str, int, float, bool, type(None))) else repr(k) for k in key]
+    result['__default__'] = debug_transport(client._transport)
+    for urlpattern, transport in client._mounts.items():
+        result[urlpattern.pattern] = debug_transport(transport)
+    return result
+
+
+def debug_asyncclients():
+    global CLIENTS
+    return [debug_asyncclient(client, key) for key, client in CLIENTS.items()]