SERVER-35168 Added ClientInfo to Session to track info about the last client to run a transaction operation on Session

3 files changed, 171 insertions, 0 deletions

diff --git a/src/mongo/db/session.cpp b/src/mongo/db/session.cpp
index 2baefb054a3..df347194ea7 100644
--- a/src/mongo/db/session.cpp
+++ b/src/mongo/db/session.cpp
@@ -742,6 +742,11 @@ void Session::stashTransactionResources(OperationContext* opCtx) {
     // We accept possible slight inaccuracies in these counters from non-atomicity.
     ServerTransactionsMetrics::get(opCtx)->decrementCurrentActive();
     ServerTransactionsMetrics::get(opCtx)->incrementCurrentInactive();
+
+    // Update the LastClientInfo object stored in the SingleTransactionStats instance on the Session
+    // with this Client's information. This is the last client that ran a transaction operation on
+    // the Session.
+    _singleTransactionStats->getLastClientInfo()->update(opCtx->getClient());
 }
 
 void Session::unstashTransactionResources(OperationContext* opCtx, const std::string& cmdName) {
@@ -918,6 +923,10 @@ void Session::abortActiveTransaction(OperationContext* opCtx) {
     // SingleTransactionStats instance on the Session.
     _singleTransactionStats->getOpDebug()->additiveMetrics.add(
         CurOp::get(opCtx)->debug().additiveMetrics);
+
+    // Update the LastClientInfo object stored in the SingleTransactionStats instance on the Session
+    // with this Client's information.
+    _singleTransactionStats->getLastClientInfo()->update(opCtx->getClient());
 }
 
 void Session::_abortTransaction(WithLock wl) {
@@ -1063,6 +1072,9 @@ void Session::_commitTransaction(stdx::unique_lock<stdx::mutex> lk, OperationCon
                 // SingleTransactionStats instance on the Session.
                 _singleTransactionStats->getOpDebug()->additiveMetrics.add(
                     CurOp::get(opCtx)->debug().additiveMetrics);
+                // Update the LastClientInfo object stored in the SingleTransactionStats instance on
+                // the Session with this Client's information.
+                _singleTransactionStats->getLastClientInfo()->update(opCtx->getClient());
             }
         }
         // We must clear the recovery unit and locker so any post-transaction writes can run without
@@ -1099,6 +1111,9 @@ void Session::_commitTransaction(stdx::unique_lock<stdx::mutex> lk, OperationCon
     // SingleTransactionStats instance on the Session.
     _singleTransactionStats->getOpDebug()->additiveMetrics.add(
         CurOp::get(opCtx)->debug().additiveMetrics);
+    // Update the LastClientInfo object stored in the SingleTransactionStats instance on the Session
+    // with this Client's information.
+    _singleTransactionStats->getLastClientInfo()->update(opCtx->getClient());
 }
 
 BSONObj Session::reportStashedState() const {
diff --git a/src/mongo/db/session_test.cpp b/src/mongo/db/session_test.cpp
index 8d1cf2f6afd..41236161fae 100644
--- a/src/mongo/db/session_test.cpp
+++ b/src/mongo/db/session_test.cpp
@@ -2279,5 +2279,127 @@ TEST_F(TransactionsMetricsTest, TimeInactiveMicrosShouldIncreaseUntilCommit) {
               timeInactiveSoFar);
 }
 
+namespace {
+
+/*
+ * Constructs a ClientMetadata BSONObj with the given application name.
+ */
+BSONObj constructClientMetadata(StringData appName) {
+    BSONObjBuilder builder;
+    ASSERT_OK(ClientMetadata::serializePrivate("driverName",
+                                               "driverVersion",
+                                               "osType",
+                                               "osName",
+                                               "osArchitecture",
+                                               "osVersion",
+                                               appName,
+                                               &builder));
+    return builder.obj();
+}
+}  // namespace
+
+TEST_F(TransactionsMetricsTest, LastClientInfoShouldUpdateUponStash) {
+    const auto sessionId = makeLogicalSessionIdForTest();
+    Session session(sessionId);
+    session.refreshFromStorageIfNeeded(opCtx());
+
+    const TxnNumber txnNum = 1;
+    opCtx()->setLogicalSessionId(sessionId);
+    opCtx()->setTxnNumber(txnNum);
+
+    // Create a ClientMetadata object and set it on ClientMetadataIsMasterState.
+    auto obj = constructClientMetadata("appName");
+    auto clientMetadata = ClientMetadata::parse(obj["client"]);
+    auto& clientMetadataIsMasterState = ClientMetadataIsMasterState::get(opCtx()->getClient());
+    clientMetadataIsMasterState.setClientMetadata(opCtx()->getClient(),
+                                                  std::move(clientMetadata.getValue()));
+
+    session.beginOrContinueTxn(opCtx(), txnNum, false, true, "testDB", "insert");
+    session.unstashTransactionResources(opCtx(), "insert");
+    // The transaction machinery cannot store an empty locker.
+    { Lock::GlobalLock lk(opCtx(), MODE_IX, Date_t::now(), Lock::InterruptBehavior::kThrow); }
+    session.stashTransactionResources(opCtx());
+
+    // LastClientInfo should have been set.
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->client, "");
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->connectionId, 0);
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->appName, "appName");
+    ASSERT_BSONOBJ_EQ(session.getSingleTransactionStats()->getLastClientInfo()->clientMetadata,
+                      obj.getField("client").Obj());
+
+    // Create another ClientMetadata object.
+    auto newObj = constructClientMetadata("newAppName");
+    auto newClientMetadata = ClientMetadata::parse(newObj["client"]);
+    clientMetadataIsMasterState.setClientMetadata(opCtx()->getClient(),
+                                                  std::move(newClientMetadata.getValue()));
+
+    session.unstashTransactionResources(opCtx(), "insert");
+    session.stashTransactionResources(opCtx());
+
+    // LastClientInfo's clientMetadata should have been updated to the new ClientMetadata object.
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->appName, "newAppName");
+    ASSERT_BSONOBJ_EQ(session.getSingleTransactionStats()->getLastClientInfo()->clientMetadata,
+                      newObj.getField("client").Obj());
+}
+
+TEST_F(TransactionsMetricsTest, LastClientInfoShouldUpdateUponCommit) {
+    const auto sessionId = makeLogicalSessionIdForTest();
+    Session session(sessionId);
+    session.refreshFromStorageIfNeeded(opCtx());
+
+    const TxnNumber txnNum = 1;
+    opCtx()->setLogicalSessionId(sessionId);
+    opCtx()->setTxnNumber(txnNum);
+
+    // Create a ClientMetadata object and set it on ClientMetadataIsMasterState.
+    auto obj = constructClientMetadata("appName");
+    auto clientMetadata = ClientMetadata::parse(obj["client"]);
+    auto& clientMetadataIsMasterState = ClientMetadataIsMasterState::get(opCtx()->getClient());
+    clientMetadataIsMasterState.setClientMetadata(opCtx()->getClient(),
+                                                  std::move(clientMetadata.getValue()));
+
+    session.beginOrContinueTxn(opCtx(), txnNum, false, true, "testDB", "insert");
+    session.unstashTransactionResources(opCtx(), "insert");
+    // The transaction machinery cannot store an empty locker.
+    Lock::GlobalLock lk(opCtx(), MODE_IX, Date_t::now(), Lock::InterruptBehavior::kThrow);
+    session.commitTransaction(opCtx());
+
+    // LastClientInfo should have been set.
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->client, "");
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->connectionId, 0);
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->appName, "appName");
+    ASSERT_BSONOBJ_EQ(session.getSingleTransactionStats()->getLastClientInfo()->clientMetadata,
+                      obj.getField("client").Obj());
+}
+
+TEST_F(TransactionsMetricsTest, LastClientInfoShouldUpdateUponAbort) {
+    const auto sessionId = makeLogicalSessionIdForTest();
+    Session session(sessionId);
+    session.refreshFromStorageIfNeeded(opCtx());
+
+    const TxnNumber txnNum = 1;
+    opCtx()->setLogicalSessionId(sessionId);
+    opCtx()->setTxnNumber(txnNum);
+
+    // Create a ClientMetadata object and set it on ClientMetadataIsMasterState.
+    auto obj = constructClientMetadata("appName");
+    auto clientMetadata = ClientMetadata::parse(obj["client"]);
+
+    auto& clientMetadataIsMasterState = ClientMetadataIsMasterState::get(opCtx()->getClient());
+    clientMetadataIsMasterState.setClientMetadata(opCtx()->getClient(),
+                                                  std::move(clientMetadata.getValue()));
+
+    session.beginOrContinueTxn(opCtx(), txnNum, false, true, "testDB", "insert");
+    session.unstashTransactionResources(opCtx(), "insert");
+    session.abortActiveTransaction(opCtx());
+
+    // LastClientInfo should have been set.
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->client, "");
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->connectionId, 0);
+    ASSERT_EQ(session.getSingleTransactionStats()->getLastClientInfo()->appName, "appName");
+    ASSERT_BSONOBJ_EQ(session.getSingleTransactionStats()->getLastClientInfo()->clientMetadata,
+                      obj.getField("client").Obj());
+}
+
 }  // namespace
 }  // namespace mongo
diff --git a/src/mongo/db/single_transaction_stats.h b/src/mongo/db/single_transaction_stats.h
index 82addddfab9..ca4dd2411ad 100644
--- a/src/mongo/db/single_transaction_stats.h
+++ b/src/mongo/db/single_transaction_stats.h
@@ -29,6 +29,8 @@
 #pragma once
 
 #include "mongo/db/curop.h"
+#include "mongo/rpc/metadata/client_metadata.h"
+#include "mongo/rpc/metadata/client_metadata_ismaster.h"
 
 namespace mongo {
 
@@ -37,6 +39,28 @@ namespace mongo {
  */
 class SingleTransactionStats {
 public:
+    /*
+     * Stores information about the last client to run a transaction operation.
+     */
+    struct LastClientInfo {
+        std::string client;
+        long long connectionId;
+        BSONObj clientMetadata;
+        std::string appName;
+
+        void update(Client* opCtxClient) {
+            if (opCtxClient->hasRemote()) {
+                client = opCtxClient->getRemote().toString();
+            }
+            connectionId = opCtxClient->getConnectionId();
+            if (const auto& metadata =
+                    ClientMetadataIsMasterState::get(opCtxClient).getClientMetadata()) {
+                clientMetadata = metadata.get().getDocument();
+                appName = metadata.get().getApplicationName().toString();
+            }
+        }
+    };
+
     /**
      * Returns the start time of the transaction in microseconds.
      *
@@ -111,6 +135,13 @@ public:
         return &_opDebug;
     }
 
+    /*
+     * Returns the LastClientInfo object stored in this SingleTransactionStats instance.
+     */
+    LastClientInfo* getLastClientInfo() {
+        return &_lastClientInfo;
+    }
+
 private:
     // The start time of the transaction in microseconds.
     unsigned long long _startTime{0};
@@ -127,6 +158,9 @@ private:
 
     // Tracks and accumulates stats from all operations that run inside the transaction.
     OpDebug _opDebug;
+
+    // Holds information about the last client to run a transaction operation.
+    LastClientInfo _lastClientInfo;
 };
 
 }  // namespace mongo