From 0879b98c60beec8f7ba86baf03a1a506e589c917 Mon Sep 17 00:00:00 2001
From: ThomasV <thomasv@electrum.org>
Date: Thu, 8 Mar 2018 15:27:21 +0100
Subject: [PATCH] use a single lock for servers

---
 lib/network.py | 37 ++++++++++++++-----------------------
 1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/lib/network.py b/lib/network.py
index 99e78641..faae5f18 100644
--- a/lib/network.py
+++ b/lib/network.py
@@ -168,6 +168,8 @@ class Network(util.DaemonThread):
 
     def __init__(self, config=None):
         self.disconnected_servers = {}
+        self.connecting = set()
+        self.servers_lock = asyncio.Lock()
         self.stopped = True
         asyncio.set_event_loop(None)
         if config is None:
@@ -384,13 +386,16 @@ class Network(util.DaemonThread):
         return out
 
     async def start_interface(self, server):
-        assert not self.connecting[server].locked()
-        async with self.connecting[server]:
+        assert server not in self.connecting
+        async with self.servers_lock:
             if (not server in self.interfaces):
                 if server == self.default_server:
                     self.print_error("connecting to %s as new interface" % server)
                     self.set_status('connecting')
-                return await self.new_interface(server)
+                self.connecting.add(server)
+                i = await self.new_interface(server)
+                self.connecting.remove(server)
+                return i
 
     async def start_random_interface(self):
         exclude_set = set(self.disconnected_servers.keys()).union(set(self.interfaces.keys()))
@@ -407,7 +412,7 @@ class Network(util.DaemonThread):
     async def start_network(self, protocol, proxy):
         self.stopped = False
         assert not self.interface and not self.interfaces
-        assert all(not i.locked() for i in self.connecting.values())
+        assert len(self.connecting) == 0
         self.print_error('starting network')
         self.protocol = protocol
         self.proxy = proxy
@@ -467,7 +472,7 @@ class Network(util.DaemonThread):
                         await self.stop_network()
                         self.print_error("STOOOOOOOOOOOOOOOOOOOOOOOOOOPPED")
                         self.default_server = server
-                        async with self.all_server_locks("restart job"):
+                        async with self.servers_lock:
                             self.disconnected_servers = {}
                         await self.start_network(protocol, proxy)
                 except BaseException as e:
@@ -734,7 +739,7 @@ class Network(util.DaemonThread):
     async def connection_down(self, server, reason=None):
         '''A connection to server either went down, or was never made.
         We distinguish by whether it is in self.interfaces.'''
-        async with self.all_server_locks("connection down"):
+        async with self.servers_lock:
             if server in self.disconnected_servers:
                 try:
                     raise Exception("already disconnected " + server + " because " + repr(self.disconnected_servers[server]) + ". new reason: " + repr(reason))
@@ -1075,29 +1080,16 @@ class Network(util.DaemonThread):
                     self.print_error("FATAL ERROR in ping_job")
         return asyncio.ensure_future(job())
 
-    def all_server_locks(self, ctx):
-        class AllLocks:
-            def __init__(self2):
-                self2.list = list(self.get_servers().keys())
-                self2.ctx = ctx
-            async def __aenter__(self2):
-                for i in self2.list:
-                    await asyncio.wait_for(self.connecting[i].acquire(), 3)
-            async def __aexit__(self2, exc_type, exc, tb):
-                for i in self2.list:
-                    self.connecting[i].release()
-        return AllLocks()
-
     async def maintain_interfaces(self):
         if self.stopped: return
 
         now = time.time()
         # nodes
-        if len(self.interfaces) + sum((1 if x.locked() else 0) for x in self.connecting.values()) < self.num_server:
+        if len(self.interfaces) + len(self.connecting) < self.num_server:
             await self.start_random_interface()
             if now - self.nodes_retry_time > NODES_RETRY_INTERVAL:
                 self.print_error('network: retrying connections')
-                async with self.all_server_locks("maintain_interfaces"):
+                async with self.servers_lock:
                     self.disconnected_servers = {}
                 self.nodes_retry_time = now
 
@@ -1109,7 +1101,7 @@ class Network(util.DaemonThread):
             else:
                 if self.default_server in self.disconnected_servers:
                     if now - self.server_retry_time > SERVER_RETRY_INTERVAL:
-                        async with self.all_server_locks("maintain_interfaces 2"):
+                        async with self.servers_locks:
                             del self.disconnected_servers[self.default_server]
                             self.server_retry_time = now
                 else:
@@ -1125,7 +1117,6 @@ class Network(util.DaemonThread):
         self.loop = loop # so we store it in the instance too
         self.init_headers_file()
         self.pending_sends = asyncio.Queue()
-        self.connecting = collections.defaultdict(asyncio.Lock)
         self.restartLock = asyncio.Lock()
 
         async def job():