Is207/reverse proxy webserver (#318)

- 1st version of the reverse proxy subsystem (see ``src/simcore_service_webserver/reverse_proxy``)
   - configurable upon setup
   - well decoupled
   - unit tests in ``tests/unit/test_reverse_proxy.py``
- customized handlers : default, jupyter and preview (drafts)
- still not integrated w/  other subsystems in webserver (will do in separated pull-request)
- connected to #207

services/director/src/simcore_service_director/registry_proxy.py

@@ -95,7 +95,7 @@ def __registry_request(path, method="GET"):
         # r = s.get(api_url, verify=False) #getattr(s, method.lower())(api_url)
         request_result = getattr(_SESSION, method.lower())(api_url)
         _logger.info("Request status: %s",request_result.status_code)
-        if request_result.status_code > 399:            
+        if request_result.status_code > 399:
             request_result.raise_for_status()
 
         return request_result

services/web/server/src/simcore_service_webserver/director.py

@@ -0,0 +1,41 @@
+""" director - subsystem that communicates with director service
+
+"""
+
+import logging
+
+from aiohttp import web
+
+from . import director_config
+
+logger = logging.getLogger(__name__)
+
+
+# SETTINGS ----------------------------------------------------
+THIS_MODULE_NAME = __name__.split(".")[-1]
+
+# --------------------------------------------------------------
+
+
+
+def setup(app: web.Application):
+    """Setup the directory sub-system in the application a la aiohttp fashion
+
+    """
+    logger.debug("Setting up %s ...", __name__)
+
+    _cfg = director_config.get_from(app)
+
+    # TODO: create instance of director's client-sdk
+
+    # TODO: inject in application
+
+
+
+
+# alias
+setup_director = setup
+
+__all__ = (
+    'setup_director'
+)

services/web/server/src/simcore_service_webserver/director_config.py

@@ -0,0 +1,41 @@
+""" director - subsystem's configuration
+
+    - defines schema for this subsystem's section in configuration file
+    - helpers functions to get/set configuration from app configuration
+
+TODO: add validation, get/set app config
+"""
+from typing import Dict
+
+import trafaret as T
+from aiohttp import web
+
+from .application_keys import APP_CONFIG_KEY
+
+
+THIS_SERVICE_NAME = 'director'
+
+
+schema = T.Dict({
+    T.Key("host", default=THIS_SERVICE_NAME): T.String(),
+    "port": T.Int()
+})
+
+
+def get_from(app: web.Application) -> Dict:
+    """ Gets section from application's config
+
+    """
+    return app[APP_CONFIG_KEY][THIS_SERVICE_NAME]
+
+
+
+# alias
+DIRECTOR_SERVICE = THIS_SERVICE_NAME
+director_schema = schema
+
+
+__all__ = (
+    "DIRECTOR_SERVICE",
+    "director_schema"
+)

services/web/server/src/simcore_service_webserver/interactive_services_manager.py

@@ -1,5 +1,7 @@
 """ Manages lifespan of interactive services.
 
+    - uses director's client-sdk to communicate with the director service
+
 """
 # pylint: disable=W0703
 # pylint: disable=C0111
@@ -20,6 +22,10 @@ def session_connect(session_id):
 
 
 async def session_disconnected(session_id):
+    """  Stops all running services when session disconnects
+
+    TODO: rename on_session_disconnected because is a reaction to that event
+    """
     log.debug("Session disconnection of session %s", session_id)
     try:
         director = director_sdk.get_director()
@@ -50,6 +56,12 @@ async def retrieve_list_of_services():
 
 
 async def start_service(session_id, service_key, service_uuid, service_version=None):
+    """ Starts a service registered in the container's registry
+
+        :param str service_key: The key (url) of the service (required)
+        :param str service_uuid: The uuid to assign the service with (required)
+        :param str service_version: The tag/version of the service
+    """
     if not service_version:
         service_version = "latest"
     log.debug("Starting service %s:%s with uuid %s", service_key, service_version, service_uuid)
@@ -68,6 +80,10 @@ async def start_service(session_id, service_key, service_uuid, service_version=N
 
 
 async def stop_service(session_id, service_uuid):
+    """ Stops and removes a running service
+
+        :param str service_uuid: The uuid to assign the service with (required)
+    """
     log.debug("Stopping service with uuid %s", service_uuid)
     try:
         director = director_sdk.get_director()

services/web/server/src/simcore_service_webserver/reverse_proxy/__init__.py

@@ -0,0 +1,54 @@
+""" reverse proxy subsystem
+
+    Dynamically reroutes communication between web-server client and dynamic-backend services  (or dyb's)
+
+ Use case
+    - All requests to `/x/{serviceId}/{proxyPath}` are re-routed to resolved dyb service
+    - dy-services are managed by the director service who monitors and controls its lifetime
+    - a client-sdk to query the director is passed upon setup
+    - Customized reverse proxy handlers for dy-jupyter, dy-modeling and dy-3dvis
+
+"""
+import logging
+
+from aiohttp import web
+
+from .abc import ServiceResolutionPolicy
+from .routing import ReverseChooser
+from .handlers import jupyter, paraview
+from .settings import URL_PATH
+
+logger = logging.getLogger(__name__)
+
+MODULE_NAME = __name__.split(".")[-1]
+
+
+def setup(app: web.Application, service_resolver: ServiceResolutionPolicy):
+    """Sets up reverse-proxy subsystem in the application (a la aiohttp)
+
+    """
+    logger.debug("Setting up %s ...", __name__)
+
+    chooser = ReverseChooser(resolver=service_resolver)
+
+    # Registers reverse proxy handlers customized for specific service types
+    chooser.register_handler(jupyter.handler,
+                             image_name=jupyter.SUPPORTED_IMAGE_NAME)
+
+    chooser.register_handler(paraview.handler,
+                             image_name=paraview.SUPPORTED_IMAGE_NAME)
+
+    # /x/{serviceId}/{proxyPath:.*}
+    app.router.add_route(method='*', path=URL_PATH,
+                         handler=chooser.do_route, name=MODULE_NAME)
+
+    # chooser has same lifetime as the application
+    app[__name__] = {"chooser": chooser}
+
+
+# alias
+setup_reverse_proxy = setup
+
+__all__ = (
+    'setup_reverse_proxy'
+)

services/web/server/src/simcore_service_webserver/reverse_proxy/abc.py

@@ -0,0 +1,36 @@
+
+import abc
+
+from yarl import URL
+
+from .settings import PROXY_MOUNTPOINT
+
+
+class ServiceResolutionPolicy(metaclass=abc.ABCMeta):
+    """ Implements an interface to identify and
+        resolve the location of a dynamic backend service
+    """
+    base_mountpoint = PROXY_MOUNTPOINT
+
+    @abc.abstractmethod
+    async def get_image_name(self, service_identifier: str) -> str:
+        """
+            Identifies a type of service. This normally corresponds
+            to the name of the docker image
+        """
+        pass
+
+    @abc.abstractmethod
+    async def find_url(self, service_identifier: str) -> URL:
+        """
+            Return the complete url (including the mountpoint) of
+            the service in the backend
+
+            This access should be accesible by the proxy server
+
+            E.g. 'http://127.0.0.1:58873/x/ae1q8/'
+        """
+        pass
+
+    # TODO: on_closed signal to notify sub-system that the service
+    # has closed and can raise HTTPServiceAnavailable

services/web/server/src/simcore_service_webserver/reverse_proxy/handlers/__init__.py

@@ -0,0 +1,3 @@
+""" Handlers customized for services
+
+"""

services/web/server/src/simcore_service_webserver/reverse_proxy/handlers/default.py

@@ -0,0 +1,58 @@
+""" Default implementation of reverse-proxy
+
+TODO: https://stackoverflow.com/questions/46788964/trying-to-build-a-proxy-with-aiohttp
+TODO: https://github.com/weargoggles/aioproxy/blob/master/aioproxy.py
+
+- another possibility: always request director and thisone will redirect to real server...
+  CONS: will double #calls
+  PROS: location of the dyb service can change at will!
+"""
+import logging
+import time
+
+import aiohttp
+from aiohttp import web
+
+from yarl import URL
+logger = logging.getLogger(__name__)
+
+
+CHUNK = 32768
+
+
+async def handler(request: web.Request, service_url: str, **_kwargs) -> web.StreamResponse:
+    # FIXME: Taken tmp from https://github.com/weargoggles/aioproxy/blob/master/aioproxy.py
+    start = time.time()
+    try:
+        # FIXME: service_url should be service_endpoint or service_origins
+        tarfind_url = URL(service_url).origin().with_path(
+            request.path).with_query(request.query)
+        async with aiohttp.client.request(
+            request.method, tarfind_url,
+            headers=request.headers,
+            chunked=CHUNK,
+            # response_class=ReverseProxyResponse,
+        ) as r:
+            logger.debug('opened backend request in %d ms',
+                         ((time.time() - start) * 1000))
+            response = aiohttp.web.StreamResponse(status=r.status,
+                                                  headers=r.headers)
+            await response.prepare(request)
+            content = r.content
+            while True:
+                chunk = await content.read(CHUNK)
+                if not chunk:
+                    break
+                await response.write(chunk)
+
+        logger.debug('finished sending content in %d ms',
+                     ((time.time() - start) * 1000,))
+        await response.write_eof()
+        return response
+    except Exception:
+        logger.debug("reverse proxy %s", request, exec_info=True)
+        raise web.HTTPServiceUnavailable(reason="Cannot talk to spawner",
+                                         content_type="application/json")
+
+    # except web.HttpStatus as status:
+    #    return status.as_response()

services/web/server/src/simcore_service_webserver/reverse_proxy/handlers/jupyter.py

@@ -0,0 +1,87 @@
+""" Reverse-proxy customized for jupyter notebooks
+
+TODO: document
+"""
+
+import asyncio
+import logging
+import pprint
+
+import aiohttp
+from aiohttp import client, web
+
+# TODO: find actual name in registry
+SUPPORTED_IMAGE_NAME = "jupyter"
+SUPPORTED_IMAGE_TAG = "==0.1.0"
+
+logger = logging.getLogger(__name__)
+
+
+async def handler(req: web.Request, service_url: str, **_kwargs) -> web.StreamResponse:
+    # Resolved url pointing to backend jupyter service
+    tarfind_url = service_url + req.path_qs
+
+    reqH = req.headers.copy()
+    if reqH['connection'] == 'Upgrade' and reqH['upgrade'] == 'websocket' and req.method == 'GET':
+
+        ws_server = web.WebSocketResponse()
+        await ws_server.prepare(req)
+        logger.info('##### WS_SERVER %s', pprint.pformat(ws_server))
+
+        client_session = aiohttp.ClientSession(cookies=req.cookies)
+        async with client_session.ws_connect(
+            tarfind_url,
+        ) as ws_client:
+            logger.info('##### WS_CLIENT %s', pprint.pformat(ws_client))
+
+            async def ws_forward(ws_from, ws_to):
+                async for msg in ws_from:
+                    logger.info('>>> msg: %s', pprint.pformat(msg))
+                    mt = msg.type
+                    md = msg.data
+                    if mt == aiohttp.WSMsgType.TEXT:
+                        await ws_to.send_str(md)
+                    elif mt == aiohttp.WSMsgType.BINARY:
+                        await ws_to.send_bytes(md)
+                    elif mt == aiohttp.WSMsgType.PING:
+                        await ws_to.ping()
+                    elif mt == aiohttp.WSMsgType.PONG:
+                        await ws_to.pong()
+                    elif ws_to.closed:
+                        await ws_to.close(code=ws_to.close_code, message=msg.extra)
+                    else:
+                        raise ValueError(
+                            'unexpected message type: %s' % pprint.pformat(msg))
+
+            await asyncio.wait([ws_forward(ws_server, ws_client), ws_forward(ws_client, ws_server)], return_when=asyncio.FIRST_COMPLETED)
+
+            return ws_server
+    else:
+
+        async with client.request(
+            req.method, tarfind_url,
+            headers=reqH,
+            allow_redirects=False,
+            data=await req.read()
+        ) as res:
+            headers = res.headers.copy()
+            body = await res.read()
+            return web.Response(
+                headers=headers,
+                status=res.status,
+                body=body
+            )
+        return ws_server
+
+
+if __name__ == "__main__":
+    # dummies for manual testing
+    BASE_URL = 'http://0.0.0.0:8888'
+    MOUNT_POINT = '/x/fakeUuid'
+
+    def adapter(req: web.Request):
+        return handler(req, service_url=BASE_URL)
+
+    app = web.Application()
+    app.router.add_route('*', MOUNT_POINT + '/{proxyPath:.*}', adapter)
+    web.run_app(app, port=3984)