SERVER-47121: Introduce pre/post handshake error handling in the RSM

17 files changed, 736 insertions, 48 deletions

diff --git a/src/mongo/base/error_codes.yml b/src/mongo/base/error_codes.yml
index 6d9cfb4eefb..99cc1b539fe 100644
--- a/src/mongo/base/error_codes.yml
+++ b/src/mongo/base/error_codes.yml
@@ -1,6 +1,7 @@
 # Group related errors into categories,can be checked against ErrorCodes::isXXXClassName methods.
 error_categories:
     - NetworkError
+    - NetworkTimeoutError
     - Interruption
     # isNotMasterError() includes all codes that indicate that the node that received the request
     # was not master at some point during command processing,regardless of whether some write may
@@ -110,7 +111,7 @@ error_codes:
     - {code: 86,name: IndexKeySpecsConflict}
     - {code: 87,name: CannotSplit}
     - {code: 88,name: SplitFailed_OBSOLETE}
-    - {code: 89,name: NetworkTimeout,categories: [NetworkError,RetriableError]}
+    - {code: 89,name: NetworkTimeout,categories: [NetworkError,RetriableError,NetworkTimeoutError]}
     - {code: 90,name: CallbackCanceled,categories: [CancelationError]}
     - {code: 91,name: ShutdownInProgress,categories: [ShutdownError,CancelationError,RetriableError]}
     - {code: 92,name: SecondaryAheadOfPrimary}
@@ -221,7 +222,7 @@ error_codes:
     - {code: 199,name: ReplicaSetMonitorRemoved}
     - {code: 200,name: ChunkRangeCleanupPending}
     - {code: 201,name: CannotBuildIndexKeys}
-    - {code: 202,name: NetworkInterfaceExceededTimeLimit,categories: [ExceededTimeLimitError]}
+    - {code: 202,name: NetworkInterfaceExceededTimeLimit,categories: [ExceededTimeLimitError,NetworkTimeoutError]}
     - {code: 203,name: ShardingStateNotInitialized}
     - {code: 204,name: TimeProofMismatch}
     - {code: 205,name: ClusterTimeFailsRateLimiter}
@@ -285,7 +286,7 @@ error_codes:
     - {code: 259,name: KeyedExecutorRetry}
     - {code: 260,name: InvalidResumeToken}
     - {code: 261,name: TooManyLogicalSessions}
-    - {code: 262,name: ExceededTimeLimit,categories: [Interruption,ExceededTimeLimitError, RetriableError]}
+    - {code: 262,name: ExceededTimeLimit,categories: [Interruption,ExceededTimeLimitError,RetriableError]}
     - {code: 263,name: OperationNotSupportedInTransaction}
     - {code: 264,name: TooManyFilesOpen}
     - {code: 265,name: OrphanedRangeCleanUpFailed}
diff --git a/src/mongo/client/SConscript b/src/mongo/client/SConscript
index 51c3df426c9..cb79546c3cd 100644
--- a/src/mongo/client/SConscript
+++ b/src/mongo/client/SConscript
@@ -199,6 +199,7 @@ clientDriverEnv.Library(
         'scanning_replica_set_monitor.cpp',
         'streamable_replica_set_monitor.cpp',
         'streamable_replica_set_monitor_query_processor.cpp',
+        'streamable_replica_set_monitor_error_handler.cpp',
         'server_is_master_monitor.cpp',
         'server_ping_monitor.cpp',
     ],
@@ -333,6 +334,7 @@ env.CppUnitTest(
         'scanning_replica_set_monitor_scan_test.cpp',
         'scanning_replica_set_monitor_test_concurrent.cpp',
         'scanning_replica_set_monitor_test_fixture.cpp',
+        'streamable_replica_set_monitor_error_handler_test.cpp',
         'server_ping_monitor_test.cpp',
     ],
     LIBDEPS=[
diff --git a/src/mongo/client/replica_set_monitor_interface.h b/src/mongo/client/replica_set_monitor_interface.h
index 3826154dfe2..ad40412dbc4 100644
--- a/src/mongo/client/replica_set_monitor_interface.h
+++ b/src/mongo/client/replica_set_monitor_interface.h
@@ -97,11 +97,17 @@ public:
      * Notifies this Monitor that a host has failed because of the specified error 'status' and
      * should be considered down.
      *
-     * Call this when you get a connection error. If you get an error while trying to refresh our
-     * view of a host, call Refresher::failedHost instead because it bypasses taking the monitor's
-     * mutex.
+     * The sdam version of the Monitor makes a distinction between failures happening before or
+     * after the initial handshake for the connection. The failedHost method is kept for backwards
+     * compatibility, and is equivalent to failedHostPostHandshake.
      */
     virtual void failedHost(const HostAndPort& host, const Status& status) = 0;
+    virtual void failedHostPreHandshake(const HostAndPort& host,
+                                        const Status& status,
+                                        BSONObj bson) = 0;
+    virtual void failedHostPostHandshake(const HostAndPort& host,
+                                         const Status& status,
+                                         BSONObj bson) = 0;
 
     /**
      * Returns true if this node is the master based ONLY on local data. Be careful, return may
diff --git a/src/mongo/client/replica_set_monitor_manager.cpp b/src/mongo/client/replica_set_monitor_manager.cpp
index 8986fd143ac..384c67c6c87 100644
--- a/src/mongo/client/replica_set_monitor_manager.cpp
+++ b/src/mongo/client/replica_set_monitor_manager.cpp
@@ -87,8 +87,23 @@ Status ReplicaSetMonitorManagerNetworkConnectionHook::validateHost(
 
             auto publisher = streamableMonitor->getEventsPublisher();
             if (publisher) {
-                publisher->onServerHandshakeCompleteEvent(
-                    isMasterReply.elapsedMillis.get(), remoteHost.toString(), isMasterReply.data);
+                try {
+                    if (isMasterReply.status.isOK()) {
+                        publisher->onServerHandshakeCompleteEvent(isMasterReply.elapsedMillis.get(),
+                                                                  remoteHost.toString(),
+                                                                  isMasterReply.data);
+                    } else {
+                        publisher->onServerHandshakeFailedEvent(
+                            remoteHost.toString(), isMasterReply.status, isMasterReply.data);
+                    }
+                } catch (const DBException& exception) {
+                    LOGV2_ERROR(4712101,
+                                "An error occurred publishing a ReplicaSetMonitor handshake event",
+                                "error"_attr = exception.toStatus(),
+                                "setName"_attr = monitor->getName(),
+                                "handshakeStatus"_attr = isMasterReply.status);
+                    return exception.toStatus();
+                }
             }
         }
     }
@@ -133,10 +148,14 @@ void ReplicaSetMonitorManager::_setupTaskExecutorInLock() {
     // construct task executor
     auto hookList = std::make_unique<rpc::EgressMetadataHookList>();
     auto networkConnectionHook = std::make_unique<ReplicaSetMonitorManagerNetworkConnectionHook>();
-    auto net = executor::makeNetworkInterface(
+
+    std::shared_ptr<NetworkInterface> networkInterface = executor::makeNetworkInterface(
         "ReplicaSetMonitor-TaskExecutor", std::move(networkConnectionHook), std::move(hookList));
-    auto pool = std::make_unique<NetworkInterfaceThreadPool>(net.get());
-    _taskExecutor = std::make_shared<ThreadPoolTaskExecutor>(std::move(pool), std::move(net));
+    _connectionManager = std::make_unique<ReplicaSetMonitorConnectionManager>(networkInterface);
+
+    auto pool = std::make_unique<NetworkInterfaceThreadPool>(networkInterface.get());
+
+    _taskExecutor = std::make_shared<ThreadPoolTaskExecutor>(std::move(pool), networkInterface);
     _taskExecutor->startup();
 }
 
@@ -173,7 +192,7 @@ shared_ptr<ReplicaSetMonitor> ReplicaSetMonitorManager::getOrCreateMonitor(const
         newMonitor->init();
     } else {
         LOGV2(4333205, "Starting Streamable ReplicaSetMonitor", "uri"_attr = uri.toString());
-        newMonitor = StreamableReplicaSetMonitor::make(uri, getExecutor());
+        newMonitor = StreamableReplicaSetMonitor::make(uri, getExecutor(), _getConnectionManager());
     }
     _monitors[setName] = newMonitor;
     return newMonitor;
@@ -220,6 +239,7 @@ void ReplicaSetMonitorManager::removeMonitor(StringData setName) {
 void ReplicaSetMonitorManager::shutdown() {
     decltype(_monitors) monitors;
     decltype(_taskExecutor) taskExecutor;
+    decltype(_connectionManager) connectionManager;
     {
         stdx::lock_guard<Latch> lk(_mutex);
         if (std::exchange(_isShutdown, true)) {
@@ -227,6 +247,7 @@ void ReplicaSetMonitorManager::shutdown() {
         }
 
         monitors = std::exchange(_monitors, {});
+        connectionManager = std::exchange(_connectionManager, {});
         taskExecutor = std::exchange(_taskExecutor, {});
     }
 
@@ -278,6 +299,11 @@ std::shared_ptr<executor::TaskExecutor> ReplicaSetMonitorManager::getExecutor()
     return _taskExecutor;
 }
 
+std::shared_ptr<executor::EgressTagCloser> ReplicaSetMonitorManager::_getConnectionManager() {
+    invariant(_connectionManager);
+    return _connectionManager;
+}
+
 ReplicaSetChangeNotifier& ReplicaSetMonitorManager::getNotifier() {
     return _notifier;
 }
@@ -286,4 +312,8 @@ bool ReplicaSetMonitorManager::isShutdown() const {
     stdx::lock_guard<Latch> lk(_mutex);
     return _isShutdown;
 }
+
+void ReplicaSetMonitorConnectionManager::dropConnections(const HostAndPort& hostAndPort) {
+    _network->dropConnections(hostAndPort);
+}
 }  // namespace mongo
diff --git a/src/mongo/client/replica_set_monitor_manager.h b/src/mongo/client/replica_set_monitor_manager.h
index de628867b6e..07b5d4e3ba4 100644
--- a/src/mongo/client/replica_set_monitor_manager.h
+++ b/src/mongo/client/replica_set_monitor_manager.h
@@ -33,7 +33,9 @@
 #include <vector>
 
 #include "mongo/client/replica_set_change_notifier.h"
+#include "mongo/executor/egress_tag_closer.h"
 #include "mongo/executor/network_connection_hook.h"
+#include "mongo/executor/network_interface.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/platform/mutex.h"
 #include "mongo/util/hierarchical_acquisition.h"
@@ -62,6 +64,30 @@ public:
                        executor::RemoteCommandResponse&& response) override;
 };
 
+class ReplicaSetMonitorConnectionManager : public executor::EgressTagCloser {
+    ReplicaSetMonitorConnectionManager() = delete;
+
+public:
+    ReplicaSetMonitorConnectionManager(std::shared_ptr<executor::NetworkInterface> network)
+        : _network(network) {}
+
+    void dropConnections(const HostAndPort& hostAndPort) override;
+
+    // Not supported.
+    void dropConnections(transport::Session::TagMask tags) override {
+        MONGO_UNREACHABLE;
+    };
+    // Not supported.
+    void mutateTags(const HostAndPort& hostAndPort,
+                    const std::function<transport::Session::TagMask(transport::Session::TagMask)>&
+                        mutateFunc) override {
+        MONGO_UNREACHABLE;
+    };
+
+private:
+    std::shared_ptr<executor::NetworkInterface> _network;
+};
+
 /**
  * Manages the lifetime of a set of replica set monitors.
  */
@@ -122,7 +148,13 @@ public:
 
     bool isShutdown() const;
 
+
 private:
+    /**
+     * Returns an EgressTagCloser controlling the executor's network interface.
+     */
+    std::shared_ptr<executor::EgressTagCloser> _getConnectionManager();
+
     using ReplicaSetMonitorsMap = StringMap<std::weak_ptr<ReplicaSetMonitor>>;
 
     // Protects access to the replica set monitors
@@ -132,6 +164,10 @@ private:
     // Executor for monitoring replica sets.
     std::shared_ptr<executor::TaskExecutor> _taskExecutor;
 
+    // Allows closing connections established by the network interface associated with the
+    // _taskExecutor instance
+    std::shared_ptr<ReplicaSetMonitorConnectionManager> _connectionManager;
+
     // Widget to notify listeners when a RSM notices a change
     ReplicaSetChangeNotifier _notifier;
 
diff --git a/src/mongo/client/scanning_replica_set_monitor.cpp b/src/mongo/client/scanning_replica_set_monitor.cpp
index 5e400d6b009..66c1fde5b27 100644
--- a/src/mongo/client/scanning_replica_set_monitor.cpp
+++ b/src/mongo/client/scanning_replica_set_monitor.cpp
@@ -356,6 +356,18 @@ void ScanningReplicaSetMonitor::failedHost(const HostAndPort& host, const Status
         _state->checkInvariants();
 }
 
+void ScanningReplicaSetMonitor::failedHostPreHandshake(const HostAndPort& host,
+                                                       const Status& status,
+                                                       BSONObj bson) {
+    failedHost(host, status);
+}
+
+void ScanningReplicaSetMonitor::failedHostPostHandshake(const HostAndPort& host,
+                                                        const Status& status,
+                                                        BSONObj bson) {
+    failedHost(host, status);
+}
+
 bool ScanningReplicaSetMonitor::isPrimary(const HostAndPort& host) const {
     stdx::lock_guard<Latch> lk(_state->mutex);
     Node* node = _state->findNode(host);
diff --git a/src/mongo/client/scanning_replica_set_monitor.h b/src/mongo/client/scanning_replica_set_monitor.h
index efd5f10be14..25208682297 100644
--- a/src/mongo/client/scanning_replica_set_monitor.h
+++ b/src/mongo/client/scanning_replica_set_monitor.h
@@ -72,8 +72,19 @@ public:
 
     HostAndPort getMasterOrUassert() override;
 
+    /*
+     * For the ScanningReplicaSetMonitor, all the failedHost methods are equivalent.
+     */
     void failedHost(const HostAndPort& host, const Status& status) override;
 
+    void failedHostPreHandshake(const HostAndPort& host,
+                                const Status& status,
+                                BSONObj bson) override;
+
+    void failedHostPostHandshake(const HostAndPort& host,
+                                 const Status& status,
+                                 BSONObj bson) override;
+
     bool isPrimary(const HostAndPort& host) const override;
 
     bool isHostUp(const HostAndPort& host) const override;
diff --git a/src/mongo/client/sdam/sdam_datatypes.cpp b/src/mongo/client/sdam/sdam_datatypes.cpp
index a6be94e3014..2faf7acd361 100644
--- a/src/mongo/client/sdam/sdam_datatypes.cpp
+++ b/src/mongo/client/sdam/sdam_datatypes.cpp
@@ -145,4 +145,24 @@ const boost::optional<TopologyVersion>& IsMasterOutcome::getTopologyVersion() co
 const std::string& IsMasterOutcome::getErrorMsg() const {
     return _errorMsg;
 }
+
+BSONObj IsMasterOutcome::toBSON() const {
+    BSONObjBuilder builder;
+    builder.append("host", _server);
+    builder.append("success", _success);
+
+    if (_errorMsg != "")
+        builder.append("errorMessage", _errorMsg);
+
+    if (_topologyVersion)
+        builder.append("topologyVersion", _topologyVersion->toBSON());
+
+    if (_rtt)
+        builder.append("duration", _rtt->toBSON());
+
+    if (_response)
+        builder.append("response", *_response);
+
+    return builder.obj();
+}
 };  // namespace mongo::sdam
diff --git a/src/mongo/client/sdam/sdam_datatypes.h b/src/mongo/client/sdam/sdam_datatypes.h
index 0da61e14d09..3ec5363965c 100644
--- a/src/mongo/client/sdam/sdam_datatypes.h
+++ b/src/mongo/client/sdam/sdam_datatypes.h
@@ -107,6 +107,7 @@ public:
     const boost::optional<IsMasterRTT>& getRtt() const;
     const boost::optional<TopologyVersion>& getTopologyVersion() const;
     const std::string& getErrorMsg() const;
+    BSONObj toBSON() const;
 
 private:
     ServerAddress _server;
diff --git a/src/mongo/client/sdam/topology_listener.cpp b/src/mongo/client/sdam/topology_listener.cpp
index 34d8ef63563..48e1f2b147b 100644
--- a/src/mongo/client/sdam/topology_listener.cpp
+++ b/src/mongo/client/sdam/topology_listener.cpp
@@ -77,6 +77,21 @@ void TopologyEventsPublisher::onServerHandshakeCompleteEvent(IsMasterRTT duratio
     _scheduleNextDelivery();
 }
 
+void TopologyEventsPublisher::onServerHandshakeFailedEvent(const sdam::ServerAddress& address,
+                                                           const Status& status,
+                                                           const BSONObj reply) {
+    {
+        stdx::lock_guard<Mutex> lock(_eventQueueMutex);
+        EventPtr event = std::make_unique<Event>();
+        event->type = EventType::HANDSHAKE_FAILURE;
+        event->hostAndPort = address;
+        event->reply = reply;
+        event->status = status;
+        _eventQueue.push_back(std::move(event));
+    }
+    _scheduleNextDelivery();
+}
+
 void TopologyEventsPublisher::onServerHeartbeatSucceededEvent(IsMasterRTT durationMs,
                                                               const ServerAddress& hostAndPort,
                                                               const BSONObj reply) {
@@ -201,6 +216,9 @@ void TopologyEventsPublisher::_sendEvent(TopologyListenerPtr listener, const Eve
         case EventType::PING_FAILURE:
             listener->onServerPingFailedEvent(event.hostAndPort, event.status);
             break;
+        case EventType::HANDSHAKE_FAILURE:
+            listener->onServerHandshakeFailedEvent(event.hostAndPort, event.status, event.reply);
+            break;
         default:
             MONGO_UNREACHABLE;
     }
diff --git a/src/mongo/client/sdam/topology_listener.h b/src/mongo/client/sdam/topology_listener.h
index 4adbb2329d2..5cc737706d0 100644
--- a/src/mongo/client/sdam/topology_listener.h
+++ b/src/mongo/client/sdam/topology_listener.h
@@ -64,6 +64,10 @@ public:
                                                 const sdam::ServerAddress& address,
                                                 const BSONObj reply = BSONObj()){};
 
+    virtual void onServerHandshakeFailedEvent(const sdam::ServerAddress& address,
+                                              const Status& status,
+                                              const BSONObj reply){};
+
     /**
      * Called when a ServerHeartBeatSucceededEvent is published - A heartbeat sent to the server at
      * hostAndPort succeeded. durationMS is the execution time of the event, including the time it
@@ -108,6 +112,11 @@ public:
     virtual void onServerHandshakeCompleteEvent(IsMasterRTT durationMs,
                                                 const sdam::ServerAddress& address,
                                                 const BSONObj reply = BSONObj()) override;
+
+    void onServerHandshakeFailedEvent(const sdam::ServerAddress& address,
+                                      const Status& status,
+                                      const BSONObj reply) override;
+
     void onServerHeartbeatSucceededEvent(IsMasterRTT durationMs,
                                          const ServerAddress& hostAndPort,
                                          const BSONObj reply) override;
@@ -126,8 +135,10 @@ private:
         PING_SUCCESS,
         PING_FAILURE,
         TOPOLOGY_DESCRIPTION_CHANGED,
-        HANDSHAKE_COMPLETE
+        HANDSHAKE_COMPLETE,
+        HANDSHAKE_FAILURE
     };
+
     struct Event {
         EventType type;
         ServerAddress hostAndPort;
diff --git a/src/mongo/client/sdam/topology_manager.cpp b/src/mongo/client/sdam/topology_manager.cpp
index 75242baa796..74f8de94d27 100644
--- a/src/mongo/client/sdam/topology_manager.cpp
+++ b/src/mongo/client/sdam/topology_manager.cpp
@@ -148,7 +148,7 @@ void TopologyManager::onServerRTTUpdated(ServerAddress hostAndPort, IsMasterRTT
     // otherwise, the server was removed from the topology. Nothing to do.
     LOGV2(4333201,
           "Not updating RTT. Server {server} does not exist in {setName}",
-          "server"_attr = hostAndPort,
+          "host"_attr = hostAndPort,
           "setName"_attr = getTopologyDescription()->getSetName());
 }
 
diff --git a/src/mongo/client/streamable_replica_set_monitor.cpp b/src/mongo/client/streamable_replica_set_monitor.cpp
index 042828f76e7..6ae640dd9af 100644
--- a/src/mongo/client/streamable_replica_set_monitor.cpp
+++ b/src/mongo/client/streamable_replica_set_monitor.cpp
@@ -63,9 +63,11 @@ using std::vector;
 
 namespace {
 // Pull nested types to top-level scope
+using executor::EgressTagCloser;
 using executor::TaskExecutor;
 using CallbackArgs = TaskExecutor::CallbackArgs;
 using CallbackHandle = TaskExecutor::CallbackHandle;
+using HandshakeStage = StreamableReplicaSetMonitorErrorHandler::HandshakeStage;
 
 const ReadPreferenceSetting kPrimaryOnlyReadPreference(ReadPreference::PrimaryOnly, TagSet());
 
@@ -140,11 +142,15 @@ constexpr auto kZeroMs = Milliseconds(0);
  * functionality. Once they are shutdown in the drop() method the operations exposed via their api
  * are effectively no-ops.
  */
-StreamableReplicaSetMonitor::StreamableReplicaSetMonitor(const MongoURI& uri,
-                                                         std::shared_ptr<TaskExecutor> executor)
+StreamableReplicaSetMonitor::StreamableReplicaSetMonitor(
+    const MongoURI& uri,
+    std::shared_ptr<TaskExecutor> executor,
+    std::shared_ptr<executor::EgressTagCloser> connectionManager)
     : _serverSelector(std::make_unique<SdamServerSelector>(kServerSelectionConfig)),
+      _errorHandler(std::make_unique<SdamErrorHandler>(uri.getSetName())),
       _queryProcessor(std::make_shared<StreamableReplicaSetMonitorQueryProcessor>()),
       _uri(uri),
+      _connectionManager(connectionManager),
       _executor(executor),
       _random(PseudoRandom(SecureRandom().nextInt64())) {
 
@@ -157,9 +163,11 @@ StreamableReplicaSetMonitor::StreamableReplicaSetMonitor(const MongoURI& uri,
     _sdamConfig = SdamConfiguration(seeds);
 }
 
-ReplicaSetMonitorPtr StreamableReplicaSetMonitor::make(const MongoURI& uri,
-                                                       std::shared_ptr<TaskExecutor> executor) {
-    auto result = std::make_shared<StreamableReplicaSetMonitor>(uri, executor);
+ReplicaSetMonitorPtr StreamableReplicaSetMonitor::make(
+    const MongoURI& uri,
+    std::shared_ptr<TaskExecutor> executor,
+    std::shared_ptr<executor::EgressTagCloser> connectionManager) {
+    auto result = std::make_shared<StreamableReplicaSetMonitor>(uri, executor, connectionManager);
     result->init();
     return result;
 }
@@ -222,7 +230,7 @@ std::vector<HostAndPort> StreamableReplicaSetMonitor::_extractHosts(
     const std::vector<ServerDescriptionPtr>& serverDescriptions) {
     std::vector<HostAndPort> result;
     for (const auto& server : serverDescriptions) {
-        result.push_back(HostAndPort(server->getAddress()));
+        result.emplace_back(server->getAddress());
     }
     return result;
 }
@@ -301,7 +309,7 @@ SemiFuture<std::vector<HostAndPort>> StreamableReplicaSetMonitor::_enqueueOutsta
             LOGV2_INFO(4333208,
                        "RSM {setName} host selection timeout: {status}",
                        "setName"_attr = getName(),
-                       "status"_attr = errorStatus.toString());
+                       "error"_attr = errorStatus.toString());
         };
     auto swDeadlineHandle = _executor->scheduleWorkAt(query->deadline, deadlineCb);
 
@@ -309,7 +317,7 @@ SemiFuture<std::vector<HostAndPort>> StreamableReplicaSetMonitor::_enqueueOutsta
         LOGV2_INFO(4333207,
                    "RSM {setName} error scheduling deadline handler: {status}",
                    "setName"_attr = getName(),
-                   "status"_attr = swDeadlineHandle.getStatus());
+                   "error"_attr = swDeadlineHandle.getStatus());
         return SemiFuture<HostAndPortList>::makeReady(swDeadlineHandle.getStatus());
     }
     query->deadlineHandle = swDeadlineHandle.getValue();
@@ -343,16 +351,53 @@ sdam::TopologyEventsPublisherPtr StreamableReplicaSetMonitor::getEventsPublisher
     return _eventsPublisher;
 }
 
-
 void StreamableReplicaSetMonitor::failedHost(const HostAndPort& host, const Status& status) {
-    failedHost(host, BSONObj(), status);
+    failedHostPostHandshake(host, status, BSONObj());
 }
 
-void StreamableReplicaSetMonitor::failedHost(const HostAndPort& host,
-                                             BSONObj bson,
-                                             const Status& status) {
-    IsMasterOutcome outcome(host.toString(), bson, status.toString());
-    _topologyManager->onServerDescription(outcome);
+void StreamableReplicaSetMonitor::failedHostPreHandshake(const HostAndPort& host,
+                                                         const Status& status,
+                                                         BSONObj bson) {
+    _failedHost(host, status, bson, HandshakeStage::kPreHandshake, true);
+}
+
+void StreamableReplicaSetMonitor::failedHostPostHandshake(const HostAndPort& host,
+                                                          const Status& status,
+                                                          BSONObj bson) {
+    _failedHost(host, status, bson, HandshakeStage::kPostHandshake, true);
+}
+
+void StreamableReplicaSetMonitor::_failedHost(const HostAndPort& host,
+                                              const Status& status,
+                                              BSONObj bson,
+                                              HandshakeStage stage,
+                                              bool isApplicationOperation) {
+    if (_isDropped.load())
+        return;
+
+    _doErrorActions(
+        host,
+        _errorHandler->computeErrorActions(host, status, stage, isApplicationOperation, bson));
+}
+
+void StreamableReplicaSetMonitor::_doErrorActions(
+    const HostAndPort& host,
+    const StreamableReplicaSetMonitorErrorHandler::ErrorActions& errorActions) const {
+    {
+        stdx::lock_guard lock(_mutex);
+        if (_isDropped.load())
+            return;
+
+        if (errorActions.dropConnections)
+            _connectionManager->dropConnections(host);
+
+        if (errorActions.requestImmediateCheck)
+            _isMasterMonitor->requestImmediateCheck();
+    }
+
+    // Call outside of the lock since this may generate a topology change event.
+    if (errorActions.isMasterOutcome)
+        _topologyManager->onServerDescription(*errorActions.isMasterOutcome);
 }
 
 boost::optional<ServerDescriptionPtr> StreamableReplicaSetMonitor::_currentPrimary() const {
@@ -556,7 +601,7 @@ void StreamableReplicaSetMonitor::onTopologyDescriptionChangedEvent(
                                 kLowerLogLevel,
                                 "Skip publishing unconfirmed replica set members since there are "
                                 "no primaries or secondaries in the new topology",
-                                "replicaSetName"_attr = getName());
+                                "setName"_attr = getName());
                     return;
                 }
 
@@ -580,29 +625,29 @@ void StreamableReplicaSetMonitor::onServerHeartbeatFailureEvent(IsMasterRTT dura
                                                                 Status errorStatus,
                                                                 const ServerAddress& hostAndPort,
                                                                 const BSONObj reply) {
-    IsMasterOutcome outcome(hostAndPort, reply, errorStatus.toString());
-    _topologyManager->onServerDescription(outcome);
+    _failedHost(
+        HostAndPort(hostAndPort), errorStatus, reply, HandshakeStage::kPostHandshake, false);
 }
 
 void StreamableReplicaSetMonitor::onServerPingFailedEvent(const ServerAddress& hostAndPort,
                                                           const Status& status) {
-    LOGV2_DEBUG(4668133,
-                0,
-                " StreamableReplicaSetMonitor::onServerPingFailedEvent, ServerPingMonitor got "
-                "status{status} ",
-                "addr"_attr = hostAndPort,
-                "status"_attr = status);
-    failedHost(HostAndPort(hostAndPort), status);
+    _failedHost(HostAndPort(hostAndPort), status, BSONObj(), HandshakeStage::kPostHandshake, false);
 }
 
+void StreamableReplicaSetMonitor::onServerHandshakeFailedEvent(const sdam::ServerAddress& address,
+                                                               const Status& status,
+                                                               const BSONObj reply) {
+    _failedHost(HostAndPort(address), status, reply, HandshakeStage::kPreHandshake, false);
+};
+
 void StreamableReplicaSetMonitor::onServerPingSucceededEvent(sdam::IsMasterRTT durationMS,
                                                              const ServerAddress& hostAndPort) {
     LOGV2_DEBUG(4668132,
-                1,
-                " StreamableReplicaSetMonitor::onServerPingSucceededEvent, ServerPingMonitor for  "
-                "{addr}  with {rtt}",
-                "addr"_attr = hostAndPort,
-                "rtt"_attr = durationMS);
+                kLowerLogLevel,
+                "ReplicaSetMonitor ping success",
+                "host"_attr = hostAndPort,
+                "setName"_attr = getName(),
+                "duration"_attr = durationMS);
     _topologyManager->onServerRTTUpdated(hostAndPort, durationMS);
 }
 
diff --git a/src/mongo/client/streamable_replica_set_monitor.h b/src/mongo/client/streamable_replica_set_monitor.h
index 5ec56495684..650d7abe237 100644
--- a/src/mongo/client/streamable_replica_set_monitor.h
+++ b/src/mongo/client/streamable_replica_set_monitor.h
@@ -41,6 +41,8 @@
 #include "mongo/client/sdam/sdam.h"
 #include "mongo/client/server_is_master_monitor.h"
 #include "mongo/client/server_ping_monitor.h"
+#include "mongo/client/streamable_replica_set_monitor_error_handler.h"
+#include "mongo/executor/egress_tag_closer.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/logger/log_component.h"
 #include "mongo/util/concurrency/with_lock.h"
@@ -76,14 +78,16 @@ public:
     static constexpr auto kCheckTimeout = Seconds(5);
 
     StreamableReplicaSetMonitor(const MongoURI& uri,
-                                std::shared_ptr<executor::TaskExecutor> executor);
+                                std::shared_ptr<executor::TaskExecutor> executor,
+                                std::shared_ptr<executor::EgressTagCloser> connectionManager);
 
     void init();
 
     void drop();
 
     static ReplicaSetMonitorPtr make(const MongoURI& uri,
-                                     std::shared_ptr<executor::TaskExecutor> executor = nullptr);
+                                     std::shared_ptr<executor::TaskExecutor> executor,
+                                     std::shared_ptr<executor::EgressTagCloser> connectionCloser);
 
     SemiFuture<HostAndPort> getHostOrRefresh(const ReadPreferenceSetting& readPref,
                                              Milliseconds maxWait = kDefaultFindHostTimeout);
@@ -93,8 +97,13 @@ public:
 
     HostAndPort getMasterOrUassert();
 
-    void failedHost(const HostAndPort& host, const Status& status);
-    void failedHost(const HostAndPort& host, BSONObj bson, const Status& status);
+    void failedHost(const HostAndPort& host, const Status& status) override;
+    void failedHostPreHandshake(const HostAndPort& host,
+                                const Status& status,
+                                BSONObj bson) override;
+    void failedHostPostHandshake(const HostAndPort& host,
+                                 const Status& status,
+                                 BSONObj bson) override;
 
     bool isPrimary(const HostAndPort& host) const;
 
@@ -147,10 +156,12 @@ private:
 
     std::vector<HostAndPort> _extractHosts(
         const std::vector<sdam::ServerDescriptionPtr>& serverDescriptions);
+
     boost::optional<std::vector<HostAndPort>> _getHosts(const TopologyDescriptionPtr& topology,
                                                         const ReadPreferenceSetting& criteria);
     boost::optional<std::vector<HostAndPort>> _getHosts(const ReadPreferenceSetting& criteria);
 
+    // Incoming Events
     void onTopologyDescriptionChangedEvent(UUID topologyId,
                                            sdam::TopologyDescriptionPtr previousDescription,
                                            sdam::TopologyDescriptionPtr newDescription) override;
@@ -159,6 +170,10 @@ private:
                                          const sdam::ServerAddress& hostAndPort,
                                          const BSONObj reply) override;
 
+    void onServerHandshakeFailedEvent(const sdam::ServerAddress& address,
+                                      const Status& status,
+                                      const BSONObj reply) override;
+
     void onServerHeartbeatFailureEvent(IsMasterRTT durationMs,
                                        Status errorStatus,
                                        const ServerAddress& hostAndPort,
@@ -197,10 +212,22 @@ private:
     // Try to satisfy the outstanding queries for this instance with the given topology information.
     void _processOutstanding(const TopologyDescriptionPtr& topologyDescription);
 
+    // Take action on error for the given host.
+    void _doErrorActions(
+        const HostAndPort& host,
+        const StreamableReplicaSetMonitorErrorHandler::ErrorActions& errorActions) const;
+
+    void _failedHost(const HostAndPort& host,
+                     const Status& status,
+                     BSONObj bson,
+                     StreamableReplicaSetMonitorErrorHandler::HandshakeStage stage,
+                     bool isApplicationOperation);
+
     sdam::SdamConfiguration _sdamConfig;
     sdam::TopologyManagerPtr _topologyManager;
     sdam::ServerSelectorPtr _serverSelector;
     sdam::TopologyEventsPublisherPtr _eventsPublisher;
+    std::unique_ptr<StreamableReplicaSetMonitorErrorHandler> _errorHandler;
     ServerIsMasterMonitorPtr _isMasterMonitor;
     std::shared_ptr<ServerPingMonitor> _pingMonitor;
 
@@ -210,6 +237,7 @@ private:
 
     const MongoURI _uri;
 
+    std::shared_ptr<executor::EgressTagCloser> _connectionManager;
     std::shared_ptr<executor::TaskExecutor> _executor;
 
     AtomicWord<bool> _isDropped{true};
diff --git a/src/mongo/client/streamable_replica_set_monitor_error_handler.cpp b/src/mongo/client/streamable_replica_set_monitor_error_handler.cpp
new file mode 100644
index 00000000000..be19b1e64ec
--- /dev/null
+++ b/src/mongo/client/streamable_replica_set_monitor_error_handler.cpp
@@ -0,0 +1,163 @@
+/**
+ *    Copyright (C) 2020-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kNetwork
+#include "mongo/client/streamable_replica_set_monitor_error_handler.h"
+
+#include "mongo/logv2/log.h"
+
+namespace mongo {
+SdamErrorHandler::ErrorActions SdamErrorHandler::computeErrorActions(const HostAndPort& host,
+                                                                     const Status& status,
+                                                                     HandshakeStage handshakeStage,
+                                                                     bool isApplicationOperation,
+                                                                     BSONObj bson) noexcept {
+    // Initial state: don't drop connections, no immediate check, and don't generate an error server
+    // description.
+    ErrorActions result;
+    ON_BLOCK_EXIT([this, &result, &host, &status] {
+        if (result.isMasterOutcome)
+            _clearConsecutiveErrorsWithoutIsMasterOutcome(host);
+
+        LOGV2(4712102,
+              "Host failed in replica set",
+              "setName"_attr = _setName,
+              "host"_attr = host,
+              "error"_attr = status,
+              "action"_attr = result);
+    });
+
+    // Helpers to mutate the actions
+    const auto setCreateServerDescriptionAction = [this, &result, &host, &status, bson]() {
+        result.isMasterOutcome = _createErrorIsMasterOutcome(host, bson, status);
+    };
+    const auto setImmediateCheckAction = [&result]() { result.requestImmediateCheck = true; };
+    const auto setDropConnectionsAction = [&result]() { result.dropConnections = true; };
+
+    if (!_isNetworkError(status) && !_isNotMasterOrNotRecovering(status)) {
+        setCreateServerDescriptionAction();
+        return result;
+    }
+
+    if (isApplicationOperation) {
+        if (_isNetworkError(status)) {
+            switch (handshakeStage) {
+                case HandshakeStage::kPreHandshake:
+                    setCreateServerDescriptionAction();
+                    break;
+                case HandshakeStage::kPostHandshake:
+                    if (!_isNetworkTimeout(status)) {
+                        setCreateServerDescriptionAction();
+                    }
+                    break;
+            }
+            setDropConnectionsAction();
+        } else if (_isNotMasterOrNotRecovering(status)) {
+            setCreateServerDescriptionAction();
+            setImmediateCheckAction();
+            if (_isNodeShuttingDown(status)) {
+                setDropConnectionsAction();
+            }
+        }
+    } else if (_isNetworkError(status)) {
+        switch (handshakeStage) {
+            case HandshakeStage::kPreHandshake:
+                setCreateServerDescriptionAction();
+                break;
+            case HandshakeStage::kPostHandshake:
+                int errorCount = _getConsecutiveErrorsWithoutIsMasterOutcome(host);
+                if (errorCount == 1) {
+                    setCreateServerDescriptionAction();
+                } else {
+                    setImmediateCheckAction();
+                    _incrementConsecutiveErrorsWithoutIsMasterOutcome(host);
+                }
+                break;
+        }
+        setDropConnectionsAction();
+    }
+
+    return result;
+}
+
+BSONObj StreamableReplicaSetMonitorErrorHandler::ErrorActions::toBSON() const {
+    BSONObjBuilder builder;
+    builder.append("dropConnections", dropConnections);
+    builder.append("requestImmediateCheck", requestImmediateCheck);
+    if (isMasterOutcome) {
+        builder.append("outcome", isMasterOutcome->toBSON());
+    }
+    return builder.obj();
+}
+
+bool SdamErrorHandler::_isNodeRecovering(const Status& status) const {
+    return ErrorCodes::isA<ErrorCategory::RetriableError>(status.code());
+}
+
+bool SdamErrorHandler::_isNetworkTimeout(const Status& status) const {
+    return ErrorCodes::isA<ErrorCategory::NetworkTimeoutError>(status.code());
+}
+
+bool SdamErrorHandler::_isNodeShuttingDown(const Status& status) const {
+    return ErrorCodes::isA<ErrorCategory::ShutdownError>(status.code());
+}
+
+bool SdamErrorHandler::_isNetworkError(const Status& status) const {
+    return ErrorCodes::isA<ErrorCategory::NetworkError>(status.code());
+}
+
+bool SdamErrorHandler::_isNotMasterOrNotRecovering(const Status& status) const {
+    return _isNodeRecovering(status) || _isNotMaster(status);
+}
+
+bool SdamErrorHandler::_isNotMaster(const Status& status) const {
+    return ErrorCodes::isA<ErrorCategory::NotMasterError>(status.code());
+}
+
+int SdamErrorHandler::_getConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host) const {
+    stdx::lock_guard lock(_mutex);
+    if (auto it = _consecutiveErrorsWithoutIsMasterOutcome.find(host);
+        it != _consecutiveErrorsWithoutIsMasterOutcome.end()) {
+        return it->second;
+    }
+    return 0;
+}
+
+void SdamErrorHandler::_incrementConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host) {
+    stdx::lock_guard lock(_mutex);
+    auto [iter, wasEmplaced] = _consecutiveErrorsWithoutIsMasterOutcome.emplace(host, 1);
+    if (!wasEmplaced) {
+        ++(iter->second);
+    }
+}
+
+void SdamErrorHandler::_clearConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host) {
+    stdx::lock_guard lock(_mutex);
+    _consecutiveErrorsWithoutIsMasterOutcome.erase(host);
+}
+}  // namespace mongo
diff --git a/src/mongo/client/streamable_replica_set_monitor_error_handler.h b/src/mongo/client/streamable_replica_set_monitor_error_handler.h
new file mode 100644
index 00000000000..86e9db135e7
--- /dev/null
+++ b/src/mongo/client/streamable_replica_set_monitor_error_handler.h
@@ -0,0 +1,94 @@
+/**
+ *    Copyright (C) 2020-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+#pragma once
+#include <boost/optional.hpp>
+
+#include "mongo/client/sdam/sdam.h"
+#include "mongo/executor/network_interface.h"
+#include "mongo/platform/mutex.h"
+#include "mongo/stdx/unordered_map.h"
+
+namespace mongo {
+class StreamableReplicaSetMonitorErrorHandler {
+public:
+    struct ErrorActions {
+        bool dropConnections = false;
+        bool requestImmediateCheck = false;
+        boost::optional<sdam::IsMasterOutcome> isMasterOutcome;
+        BSONObj toBSON() const;
+    };
+
+    // Indicates whether the initial handshake has completed.
+    enum class HandshakeStage { kPreHandshake, kPostHandshake };
+
+    virtual ~StreamableReplicaSetMonitorErrorHandler() = default;
+
+    // Based on the error status, source of the error, and handshake stage determine what
+    // ErrorActions we should take.
+    virtual ErrorActions computeErrorActions(const HostAndPort& host,
+                                             const Status& status,
+                                             HandshakeStage handshakeStage,
+                                             bool isApplicationOperation,
+                                             BSONObj bson) noexcept = 0;
+
+protected:
+    sdam::IsMasterOutcome _createErrorIsMasterOutcome(const HostAndPort& host,
+                                                      boost::optional<BSONObj> bson,
+                                                      const Status& status) const {
+        return sdam::IsMasterOutcome(host.toString(), bson ? *bson : BSONObj(), status.toString());
+    }
+};
+
+class SdamErrorHandler final : public StreamableReplicaSetMonitorErrorHandler {
+public:
+    explicit SdamErrorHandler(std::string setName) : _setName(std::move(setName)){};
+
+    ErrorActions computeErrorActions(const HostAndPort& host,
+                                     const Status& status,
+                                     HandshakeStage handshakeStage,
+                                     bool isApplicationOperation,
+                                     BSONObj bson) noexcept override;
+
+private:
+    int _getConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host) const;
+    void _incrementConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host);
+    void _clearConsecutiveErrorsWithoutIsMasterOutcome(const HostAndPort& host);
+
+    bool _isNodeRecovering(const Status& status) const;
+    bool _isNetworkTimeout(const Status& status) const;
+    bool _isNodeShuttingDown(const Status& status) const;
+    bool _isNetworkError(const Status& status) const;
+    bool _isNotMasterOrNotRecovering(const Status& status) const;
+    bool _isNotMaster(const Status& status) const;
+
+    const std::string _setName;
+    mutable Mutex _mutex;
+    stdx::unordered_map<HostAndPort, int> _consecutiveErrorsWithoutIsMasterOutcome;
+};
+}  // namespace mongo
diff --git a/src/mongo/client/streamable_replica_set_monitor_error_handler_test.cpp b/src/mongo/client/streamable_replica_set_monitor_error_handler_test.cpp
new file mode 100644
index 00000000000..45aea46b787
--- /dev/null
+++ b/src/mongo/client/streamable_replica_set_monitor_error_handler_test.cpp
@@ -0,0 +1,210 @@
+/**
+ *    Copyright (C) 2020-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kNetwork
+#include "mongo/client/streamable_replica_set_monitor_error_handler.h"
+
+#include <boost/optional/optional_io.hpp>
+
+#include "mongo/client/sdam/sdam.h"
+#include "mongo/logv2/log.h"
+#include "mongo/platform/basic.h"
+#include "mongo/unittest/unittest.h"
+
+namespace mongo {
+using HandshakeStage = StreamableReplicaSetMonitorErrorHandler::HandshakeStage;
+using ErrorActions = StreamableReplicaSetMonitorErrorHandler::ErrorActions;
+using Error = ErrorCodes::Error;
+
+class StreamableReplicaSetMonitorErrorHandlerTestFixture : public unittest::Test {
+public:
+    Status makeStatus(Error error) {
+        return Status(error, kErrorMessage);
+    }
+
+    void verifyActions(ErrorActions result, ErrorActions expectedResult) {
+        ASSERT_EQUALS(result.dropConnections, expectedResult.dropConnections);
+        ASSERT_EQUALS(result.requestImmediateCheck, expectedResult.requestImmediateCheck);
+        if (expectedResult.isMasterOutcome) {
+            ASSERT_FALSE(result.isMasterOutcome->isSuccess());
+            std::string resultError = result.isMasterOutcome->getErrorMsg();
+            ASSERT_NOT_EQUALS(resultError.find(expectedResult.isMasterOutcome->getErrorMsg()),
+                              std::string::npos);
+        } else {
+            ASSERT_FALSE(result.isMasterOutcome);
+        }
+    }
+
+    void testScenario(HandshakeStage stage,
+                      bool isApplicationOperation,
+                      std::vector<Error> errors,
+                      std::function<ErrorActions(const Status&)> expectedResultGenerator,
+                      int numAttempts = 1) {
+        auto testSubject = subject();
+
+        const auto prePost = (stage == HandshakeStage::kPreHandshake) ? "pre" : "post";
+        const auto applicationOperation = (isApplicationOperation) ? "application" : "monitoring";
+        LOGV2_INFO(4712105,
+                   "Check Scenario",
+                   "handshake"_attr = prePost,
+                   "operationType"_attr = applicationOperation);
+        for (auto error : errors) {
+            LOGV2_INFO(4712106, "Check error ", "error"_attr = ErrorCodes::errorString(error));
+            for (int attempt = 0; attempt < numAttempts; attempt++) {
+                auto result = testSubject->computeErrorActions(
+                    kHost, makeStatus(error), stage, isApplicationOperation, kErrorBson);
+                verifyActions(result, expectedResultGenerator(makeStatus(error)));
+                LOGV2_INFO(4712107, "Attempt Successful", "num"_attr = attempt);
+            }
+        }
+    }
+
+    void testScenario(HandshakeStage stage,
+                      bool isApplicationOperation,
+                      std::vector<Error> errors,
+                      ErrorActions expectedResult,
+                      int numAttempts = 1) {
+        testScenario(stage, isApplicationOperation, errors, [expectedResult](const Status&) {
+            return expectedResult;
+        });
+    }
+
+    std::unique_ptr<StreamableReplicaSetMonitorErrorHandler> subject() {
+        return std::make_unique<SdamErrorHandler>(kSetName);
+    }
+
+    inline static const std::vector<Error> kNetworkErrors{ErrorCodes::SocketException,
+                                                          ErrorCodes::NetworkTimeout,
+                                                          ErrorCodes::HostNotFound,
+                                                          ErrorCodes::HostUnreachable};
+    inline static const std::vector<Error> kNetworkErrorsNoTimeout{
+        ErrorCodes::SocketException, ErrorCodes::HostNotFound, ErrorCodes::HostUnreachable};
+    inline static const std::vector<Error> kInternalError{ErrorCodes::InternalError};
+    inline static const std::vector<Error> kNotMasterAndNodeRecovering{
+        ErrorCodes::InterruptedAtShutdown,
+        ErrorCodes::InterruptedDueToReplStateChange,
+        ErrorCodes::NotMasterOrSecondary,
+        ErrorCodes::PrimarySteppedDown,
+        ErrorCodes::ShutdownInProgress,
+        ErrorCodes::NotMaster,
+        ErrorCodes::NotMasterNoSlaveOk};
+
+    inline static const std::string kSetName = "setName";
+    inline static const HostAndPort kHost = HostAndPort("foobar:123");
+    inline static const std::string kErrorMessage = "an error message";
+    inline static const BSONObj kErrorBson = BSONObjBuilder().append("ok", 0).obj();
+    inline static const sdam::IsMasterOutcome kErrorIsMasterOutcome =
+        sdam::IsMasterOutcome(kHost.toString(), kErrorBson, kErrorMessage);
+
+    static constexpr bool kApplicationOperation = true;
+    static constexpr bool kMonitoringOperation = false;
+
+    static constexpr int kThreeAttempts = 3;
+};
+
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, ApplicationNetworkErrorsPreHandshake) {
+    testScenario(
+        HandshakeStage::kPreHandshake,
+        kApplicationOperation,
+        kNetworkErrors,
+        StreamableReplicaSetMonitorErrorHandler::ErrorActions{true, false, kErrorIsMasterOutcome});
+};
+
+// https://github.com/mongodb/specifications/blob/master/source/server-discovery-and-monitoring/server-discovery-and-monitoring.rst#network-error-when-reading-or-writing
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, ApplicationNetworkErrorsPostHandshake) {
+    testScenario(
+        HandshakeStage::kPostHandshake,
+        kApplicationOperation,
+        kNetworkErrorsNoTimeout,
+        StreamableReplicaSetMonitorErrorHandler::ErrorActions{true, false, kErrorIsMasterOutcome});
+};
+
+// https://github.com/mongodb/specifications/blob/master/source/server-discovery-and-monitoring/server-monitoring.rst#network-error-during-server-check
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, MonitoringNetworkErrorsPostHandshake) {
+    // Two consecutive errors must occur to expect an unknown server description.
+    const auto errorServerDescriptionOnSecondNetworkFailure = [](const Status& status) {
+        static int count = 0;
+        count = (count + 1) % 2;
+        return (count == 1)
+            ? StreamableReplicaSetMonitorErrorHandler::ErrorActions{true, true, boost::none}
+            : StreamableReplicaSetMonitorErrorHandler::ErrorActions{
+                  true, false, kErrorIsMasterOutcome};
+    };
+
+    testScenario(HandshakeStage::kPostHandshake,
+                 kMonitoringOperation,
+                 kNetworkErrors,
+                 errorServerDescriptionOnSecondNetworkFailure,
+                 kThreeAttempts);
+}
+
+// https://github.com/mongodb/specifications/blob/master/source/server-discovery-and-monitoring/server-monitoring.rst#network-error-during-server-check
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, MonitoringNetworkErrorsPreHandshake) {
+    testScenario(
+        HandshakeStage::kPreHandshake,
+        kMonitoringOperation,
+        kNetworkErrors,
+        StreamableReplicaSetMonitorErrorHandler::ErrorActions{true, false, kErrorIsMasterOutcome},
+        kThreeAttempts);
+}
+
+// https://github.com/mongodb/specifications/blob/master/source/server-discovery-and-monitoring/server-discovery-and-monitoring.rst#not-master-and-node-is-recovering
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, ApplicationNotMasterOrNodeRecovering) {
+    const auto shutdownErrorsDropConnections = [](const Status& status) {
+        if (ErrorCodes::isA<ErrorCategory::ShutdownError>(status.code())) {
+            return StreamableReplicaSetMonitorErrorHandler::ErrorActions{
+                true, true, kErrorIsMasterOutcome};
+        } else {
+            return StreamableReplicaSetMonitorErrorHandler::ErrorActions{
+                false, true, kErrorIsMasterOutcome};
+        }
+    };
+
+    testScenario(HandshakeStage::kPostHandshake,
+                 kApplicationOperation,
+                 kNotMasterAndNodeRecovering,
+                 shutdownErrorsDropConnections);
+}
+
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture, MonitoringNonNetworkError) {
+    testScenario(
+        HandshakeStage::kPostHandshake,
+        kMonitoringOperation,
+        kInternalError,
+        StreamableReplicaSetMonitorErrorHandler::ErrorActions{false, false, kErrorIsMasterOutcome});
+}
+
+TEST_F(StreamableReplicaSetMonitorErrorHandlerTestFixture,
+       ApplicationNonNetworkIsMasterOrRecoveringError) {
+    testScenario(
+        HandshakeStage::kPostHandshake,
+        kMonitoringOperation,
+        kInternalError,
+        StreamableReplicaSetMonitorErrorHandler::ErrorActions{false, false, kErrorIsMasterOutcome});
+}
+}  // namespace mongo