From 5c6ec96d6477371d8e617bcc71e6ecbcdd5c78cc Mon Sep 17 00:00:00 2001
From: John Roberts <8711996+johnroberts755@users.noreply.github.com>
Date: Thu, 10 Mar 2022 10:49:22 +0400
Subject: [PATCH] make smp servers configurable for running agent (#326)

---
 apps/smp-agent/Main.hs                    |  2 +-
 src/Simplex/Messaging/Agent.hs            | 21 ++++++++++++++++-----
 src/Simplex/Messaging/Agent/Client.hs     |  5 ++++-
 src/Simplex/Messaging/Agent/Env/SQLite.hs |  4 ++--
 src/Simplex/Messaging/Protocol.hs         |  4 ++++
 tests/SMPAgentClient.hs                   |  4 ++--
 6 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/apps/smp-agent/Main.hs b/apps/smp-agent/Main.hs
index 1087530f9..32e038f56 100644
--- a/apps/smp-agent/Main.hs
+++ b/apps/smp-agent/Main.hs
@@ -11,7 +11,7 @@ import Simplex.Messaging.Agent.Server (runSMPAgent)
 import Simplex.Messaging.Transport (TLS, Transport (..))
 
 cfg :: AgentConfig
-cfg = defaultAgentConfig {smpServers = L.fromList ["smp://bU0K-bRg24xWW__lS0umO1Zdw_SXqpJNtm1_RrPLViE=@localhost:5223"]}
+cfg = defaultAgentConfig {initialSMPServers = L.fromList ["smp://bU0K-bRg24xWW__lS0umO1Zdw_SXqpJNtm1_RrPLViE=@localhost:5223"]}
 
 logCfg :: LogConfig
 logCfg = LogConfig {lc_file = Nothing, lc_stderr = True}
diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index 7b4e202bd..f96e8a723 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -47,6 +47,7 @@ module Simplex.Messaging.Agent
     ackMessage,
     suspendConnection,
     deleteConnection,
+    setSMPServers,
     logConnection,
   )
 where
@@ -143,6 +144,10 @@ suspendConnection c = withAgentEnv c . suspendConnection' c
 deleteConnection :: AgentErrorMonad m => AgentClient -> ConnId -> m ()
 deleteConnection c = withAgentEnv c . deleteConnection' c
 
+-- | Change servers to be used for creating new queues
+setSMPServers :: AgentErrorMonad m => AgentClient -> NonEmpty SMPServer -> m ()
+setSMPServers c = withAgentEnv c . setSMPServers' c
+
 withAgentEnv :: AgentClient -> ReaderT Env m a -> m a
 withAgentEnv c = (`runReaderT` agentEnv c)
 
@@ -209,7 +214,7 @@ processCommand c (connId, cmd) = case cmd of
 
 newConn :: AgentMonad m => AgentClient -> ConnId -> SConnectionMode c -> m (ConnId, ConnectionRequestUri c)
 newConn c connId cMode = do
-  srv <- getSMPServer
+  srv <- getSMPServer c
   (rq, qUri) <- newRcvQueue c srv
   g <- asks idsDrg
   let cData = ConnData {connId}
@@ -262,7 +267,7 @@ joinConn c connId (CRContactUri (ConnReqUriData _ agentVRange (qUri :| _))) cInf
 
 createReplyQueue :: AgentMonad m => AgentClient -> ConnId -> SndQueue -> m ()
 createReplyQueue c connId sq = do
-  srv <- getSMPServer
+  srv <- getSMPServer c
   (rq, qUri) <- newRcvQueue c srv
   -- TODO reply queue version should be the same as send queue, ignoring it in v1
   let qInfo = toVersionT qUri SMP.smpClientVersion
@@ -488,9 +493,15 @@ deleteConnection' c connId =
       removeSubscription c connId
       withStore (`deleteConn` connId)
 
-getSMPServer :: AgentMonad m => m SMPServer
-getSMPServer =
-  asks (smpServers . config) >>= \case
+-- | Change servers to be used for creating new queues, in Reader monad
+setSMPServers' :: forall m. AgentMonad m => AgentClient -> NonEmpty SMPServer -> m ()
+setSMPServers' c servers = do
+  atomically $ writeTVar (smpServers c) servers
+
+getSMPServer :: AgentMonad m => AgentClient -> m SMPServer
+getSMPServer c = do
+  smpServers <- readTVarIO $ smpServers c
+  case smpServers of
     srv :| [] -> pure srv
     servers -> do
       gen <- asks randomServer
diff --git a/src/Simplex/Messaging/Agent/Client.hs b/src/Simplex/Messaging/Agent/Client.hs
index c2f87f764..140bcb20b 100644
--- a/src/Simplex/Messaging/Agent/Client.hs
+++ b/src/Simplex/Messaging/Agent/Client.hs
@@ -47,6 +47,7 @@ import Data.Bifunctor (first)
 import Data.ByteString.Base64
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
+import Data.List.NonEmpty (NonEmpty)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
 import Data.Maybe (isNothing)
@@ -76,6 +77,7 @@ data AgentClient = AgentClient
   { rcvQ :: TBQueue (ATransmission 'Client),
     subQ :: TBQueue (ATransmission 'Agent),
     msgQ :: TBQueue SMPServerTransmission,
+    smpServers :: TVar (NonEmpty SMPServer),
     smpClients :: TVar (Map SMPServer SMPClientVar),
     subscrSrvrs :: TVar (Map SMPServer (Map ConnId RcvQueue)),
     pendingSubscrSrvrs :: TVar (Map SMPServer (Map ConnId RcvQueue)),
@@ -97,6 +99,7 @@ newAgentClient agentEnv = do
   rcvQ <- newTBQueue qSize
   subQ <- newTBQueue qSize
   msgQ <- newTBQueue qSize
+  smpServers <- newTVar $ initialSMPServers (config agentEnv)
   smpClients <- newTVar M.empty
   subscrSrvrs <- newTVar M.empty
   pendingSubscrSrvrs <- newTVar M.empty
@@ -108,7 +111,7 @@ newAgentClient agentEnv = do
   asyncClients <- newTVar []
   clientId <- stateTVar (clientCounter agentEnv) $ \i -> (i + 1, i + 1)
   lock <- newTMVar ()
-  return AgentClient {rcvQ, subQ, msgQ, smpClients, subscrSrvrs, pendingSubscrSrvrs, subscrConns, connMsgsQueued, smpQueueMsgQueues, smpQueueMsgDeliveries, reconnections, asyncClients, clientId, agentEnv, smpSubscriber = undefined, lock}
+  return AgentClient {rcvQ, subQ, msgQ, smpServers, smpClients, subscrSrvrs, pendingSubscrSrvrs, subscrConns, connMsgsQueued, smpQueueMsgQueues, smpQueueMsgDeliveries, reconnections, asyncClients, clientId, agentEnv, smpSubscriber = undefined, lock}
 
 -- | Agent monad with MonadReader Env and MonadError AgentErrorType
 type AgentMonad m = (MonadUnliftIO m, MonadReader Env m, MonadError AgentErrorType m)
diff --git a/src/Simplex/Messaging/Agent/Env/SQLite.hs b/src/Simplex/Messaging/Agent/Env/SQLite.hs
index ba54d00bc..a1f03cf6f 100644
--- a/src/Simplex/Messaging/Agent/Env/SQLite.hs
+++ b/src/Simplex/Messaging/Agent/Env/SQLite.hs
@@ -29,7 +29,7 @@ import UnliftIO.STM
 
 data AgentConfig = AgentConfig
   { tcpPort :: ServiceName,
-    smpServers :: NonEmpty SMPServer,
+    initialSMPServers :: NonEmpty SMPServer,
     cmdSignAlg :: C.SignAlg,
     connIdBytes :: Int,
     tbqSize :: Natural,
@@ -48,7 +48,7 @@ defaultAgentConfig :: AgentConfig
 defaultAgentConfig =
   AgentConfig
     { tcpPort = "5224",
-      smpServers = undefined, -- TODO move it elsewhere?
+      initialSMPServers = undefined, -- TODO move it elsewhere?
       cmdSignAlg = C.SignAlg C.SEd448,
       connIdBytes = 12,
       tbqSize = 64,
diff --git a/src/Simplex/Messaging/Protocol.hs b/src/Simplex/Messaging/Protocol.hs
index 0705ad697..0d148bf04 100644
--- a/src/Simplex/Messaging/Protocol.hs
+++ b/src/Simplex/Messaging/Protocol.hs
@@ -399,6 +399,10 @@ instance StrEncoding SMPServer where
     SrvLoc host port <- strP
     pure SMPServer {host, port, keyHash}
 
+instance ToJSON SMPServer where
+  toJSON = strToJSON
+  toEncoding = strToJEncoding
+
 data SrvLoc = SrvLoc HostName ServiceName
   deriving (Eq, Ord, Show)
 
diff --git a/tests/SMPAgentClient.hs b/tests/SMPAgentClient.hs
index 4cf4f308a..8c144509e 100644
--- a/tests/SMPAgentClient.hs
+++ b/tests/SMPAgentClient.hs
@@ -157,7 +157,7 @@ cfg :: AgentConfig
 cfg =
   defaultAgentConfig
     { tcpPort = agentTestPort,
-      smpServers = L.fromList ["smp://LcJUMfVhwD8yxjAiSaDzzGF3-kLG4Uh0Fl_ZIjrRwjI=@localhost:5001"],
+      initialSMPServers = L.fromList ["smp://LcJUMfVhwD8yxjAiSaDzzGF3-kLG4Uh0Fl_ZIjrRwjI=@localhost:5001"],
       tbqSize = 1,
       dbFile = testDB,
       smpCfg =
@@ -174,7 +174,7 @@ cfg =
 
 withSmpAgentThreadOn_ :: (MonadUnliftIO m, MonadRandom m) => ATransport -> (ServiceName, ServiceName, String) -> m () -> (ThreadId -> m a) -> m a
 withSmpAgentThreadOn_ t (port', smpPort', db') afterProcess =
-  let cfg' = cfg {tcpPort = port', dbFile = db', smpServers = L.fromList [SMPServer "localhost" smpPort' testKeyHash]}
+  let cfg' = cfg {tcpPort = port', dbFile = db', initialSMPServers = L.fromList [SMPServer "localhost" smpPort' testKeyHash]}
    in serverBracket
         (\started -> runSMPAgentBlocking t started cfg')
         afterProcess