SERVER-84283 Return const reference from Shard::getConnString

GitOrigin-RevId: aafa09c

Author: jsmulrow

src/mongo/db/s/shard_local.cpp

@@ -43,15 +43,16 @@
 
 namespace mongo {
 
+const ConnectionString ShardLocal::kLocalConnectionString = ConnectionString::forLocal();
+
 ShardLocal::ShardLocal(const ShardId& id) : Shard(id) {
     // Currently ShardLocal only works for config servers. If we ever start using ShardLocal on
     // shards we'll need to consider how to handle shards.
     invariant(serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer));
 }
 
-ConnectionString ShardLocal::getConnString() const {
-    return repl::ReplicationCoordinator::get(getGlobalServiceContext())
-        ->getConfigConnectionString();
+const ConnectionString& ShardLocal::getConnString() const {
+    return kLocalConnectionString;
 }
 
 std::shared_ptr<RemoteCommandTargeter> ShardLocal::getTargeter() const {

src/mongo/db/s/shard_local.h

@@ -61,6 +61,10 @@ class ShardLocal : public Shard {
     ShardLocal& operator=(const ShardLocal&) = delete;
 
 public:
+    // ShardLocal doesn't have a "real" connection string since it's always a connection to the
+    // local process, so it uses the hardcoded local connection string. Only used in tests.
+    static const ConnectionString kLocalConnectionString;
+
     explicit ShardLocal(const ShardId& id);
 
     ~ShardLocal() = default;
@@ -69,7 +73,7 @@ class ShardLocal : public Shard {
      * These functions are implemented for the Shard interface's sake. They should not be called on
      * ShardLocal because doing so triggers invariants.
      */
-    ConnectionString getConnString() const override;
+    const ConnectionString& getConnString() const override;
     std::shared_ptr<RemoteCommandTargeter> getTargeter() const override;
     void updateReplSetMonitor(const HostAndPort& remoteHost,
                               const Status& remoteCommandStatus) override;

src/mongo/s/client/config_shard_wrapper.cpp

@@ -44,7 +44,7 @@ ConfigShardWrapper::ConfigShardWrapper(std::shared_ptr<Shard> configShard)
     invariant(_configShard->isConfig());
 }
 
-ConnectionString ConfigShardWrapper::getConnString() const {
+const ConnectionString& ConfigShardWrapper::getConnString() const {
     return _configShard->getConnString();
 }
 

src/mongo/s/client/config_shard_wrapper.h

@@ -72,7 +72,7 @@ class ConfigShardWrapper : public Shard {
 
     ~ConfigShardWrapper() = default;
 
-    ConnectionString getConnString() const override;
+    const ConnectionString& getConnString() const override;
 
     std::shared_ptr<RemoteCommandTargeter> getTargeter() const override;
 

src/mongo/s/client/config_shard_wrapper_test.cpp

@@ -53,6 +53,9 @@
 namespace mongo {
 namespace {
 
+const HostAndPort kConfigHost{"configHost1"};
+ConnectionString kConfigCS{ConnectionString::forReplicaSet("configReplSet", {kConfigHost})};
+
 class MockShard : public Shard {
     MockShard(const MockShard&) = delete;
     MockShard& operator=(const MockShard&) = delete;
@@ -61,10 +64,8 @@ class MockShard : public Shard {
     explicit MockShard(const ShardId& id) : Shard(id) {}
     ~MockShard() = default;
 
-    ConnectionString getConnString() const override {
-        const HostAndPort configHost{"configHost1"};
-        ConnectionString configCS{ConnectionString::forReplicaSet("configReplSet", {configHost})};
-        return configCS;
+    const ConnectionString& getConnString() const override {
+        return kConfigCS;
     }
 
     std::shared_ptr<RemoteCommandTargeter> getTargeter() const override {

src/mongo/s/client/shard.h

@@ -128,7 +128,7 @@ class Shard {
     /**
      * Returns the current connection string for the shard.
      */
-    virtual ConnectionString getConnString() const = 0;
+    virtual const ConnectionString& getConnString() const = 0;
 
     /**
      * Returns the RemoteCommandTargeter for the hosts in this shard.

src/mongo/s/client/shard_remote.h

@@ -74,7 +74,7 @@ class ShardRemote : public Shard {
 
     ~ShardRemote();
 
-    ConnectionString getConnString() const override {
+    const ConnectionString& getConnString() const override {
         return _connString;
     }