Fix typo

Co-Authored-By: anoadragon453 <1342360+anoadragon453@users.noreply.github.com>

changelog.d/4406.feature

@@ -0,0 +1 @@
+Add a simple HTTP proxy option for Synapse to send federation traffic through before reaching other servers.

synapse/config/server.py

@@ -107,12 +107,23 @@ class ServerConfig(Config):
         federation_domain_whitelist = config.get(
             "federation_domain_whitelist", None
         )
+
         # turn the whitelist into a hash for speed of lookup
         if federation_domain_whitelist is not None:
             self.federation_domain_whitelist = {}
             for domain in federation_domain_whitelist:
                 self.federation_domain_whitelist[domain] = True
 
+        # Optional proxy address for federation traffic
+        self.federation_request_gateway_addr = config.get(
+            "federation_request_gateway_addr", None
+        )
+
+        if self.federation_request_gateway_addr is not None:
+            # Ensure proxy address is correctly formatted
+            if len(self.federation_request_gateway_addr.split(':')) != 2:
+                self.federation_request_gateway_addr = None
+
         if self.public_baseurl is not None:
             if self.public_baseurl[-1] != '/':
                 self.public_baseurl += '/'
@@ -289,6 +300,11 @@ class ServerConfig(Config):
         #  - nyc.example.com
         #  - syd.example.com
 
+        # Send outbound federation requests through a seperate traffic gateway.
+        # Not intended to be used with a SOCKS proxy, but rather a relay for
+        # HTTP traffic.
+        # federation_request_gateway_addr: localhost:1234
+
         # List of ports that Synapse should listen on, their purpose and their
         # configuration.
         listeners:

synapse/http/matrixfederationclient.py

@@ -56,7 +56,6 @@ outgoing_requests_counter = Counter("synapse_http_matrixfederationclient_request
 incoming_responses_counter = Counter("synapse_http_matrixfederationclient_responses",
                                      "", ["method", "code"])
 
-
 MAX_LONG_RETRIES = 10
 MAX_SHORT_RETRIES = 3
 
@@ -66,6 +65,19 @@ else:
     MAXINT = sys.maxint
 
 
+class ProxyMatrixFederationEndpointFactory(object):
+    def __init__(self, hs):
+        self.reactor = hs.get_reactor()
+        self.tls_client_options_factory = hs.tls_client_options_factory
+        self.gateway_addr = hs.config.federation_request_gateway_addr
+
+    def endpointForURI(self, uri):
+        return matrix_federation_endpoint(
+            self.reactor, self.gateway_addr, timeout=10,
+            tls_client_options_factory=None
+        )
+
+
 class MatrixFederationEndpointFactory(object):
     def __init__(self, hs):
         self.reactor = hs.get_reactor()
@@ -186,14 +198,22 @@ class MatrixFederationHttpClient(object):
         self.hs = hs
         self.signing_key = hs.config.signing_key[0]
         self.server_name = hs.hostname
+        self.gateway_addr = hs.config.federation_request_gateway_addr
         reactor = hs.get_reactor()
         pool = HTTPConnectionPool(reactor)
         pool.retryAutomatically = False
         pool.maxPersistentPerHost = 5
         pool.cachedConnectionTimeout = 2 * 60
-        self.agent = Agent.usingEndpointFactory(
-            reactor, MatrixFederationEndpointFactory(hs), pool=pool
-        )
+
+        if self.gateway_addr:
+            self.agent = Agent.usingEndpointFactory(
+                reactor, ProxyMatrixFederationEndpointFactory(hs), pool=pool
+            )
+        else:
+            self.agent = Agent.usingEndpointFactory(
+                reactor, MatrixFederationEndpointFactory(hs), pool=pool
+            )
+
         self.clock = hs.get_clock()
         self._store = hs.get_datastore()
         self.version_string_bytes = hs.version_string.encode('ascii')

tests/utils.py

@@ -115,6 +115,7 @@ def default_config(name):
     config.email_enable_notifs = False
     config.block_non_admin_invites = False
     config.federation_domain_whitelist = None
+    config.federation_request_gateway_addr = None
     config.federation_rc_reject_limit = 10
     config.federation_rc_sleep_limit = 10
     config.federation_rc_sleep_delay = 100