SERVER-47096 Add ReplSetMetadata.configTerm

3 files changed, 44 insertions, 17 deletions

diff --git a/src/mongo/rpc/metadata/repl_set_metadata.cpp b/src/mongo/rpc/metadata/repl_set_metadata.cpp
index 9698ded3eb5..2d01a732960 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata.cpp
+++ b/src/mongo/rpc/metadata/repl_set_metadata.cpp
@@ -49,6 +49,7 @@ const char kLastOpCommittedFieldName[] = "lastOpCommitted";
 const char kLastCommittedWallFieldName[] = "lastCommittedWall";
 const char kLastOpVisibleFieldName[] = "lastOpVisible";
 const char kConfigVersionFieldName[] = "configVersion";
+const char kConfigTermFieldName[] = "configTerm";
 const char kReplicaSetIdFieldName[] = "replicaSetId";
 const char kPrimaryIndexFieldName[] = "primaryIndex";
 const char kSyncSourceIndexFieldName[] = "syncSourceIndex";
@@ -63,6 +64,7 @@ ReplSetMetadata::ReplSetMetadata(long long term,
                                  OpTimeAndWallTime committedOpTime,
                                  OpTime visibleOpTime,
                                  long long configVersion,
+                                 long long configTerm,
                                  OID id,
                                  int currentPrimaryIndex,
                                  int currentSyncSourceIndex,
@@ -71,6 +73,7 @@ ReplSetMetadata::ReplSetMetadata(long long term,
       _lastOpVisible(std::move(visibleOpTime)),
       _currentTerm(term),
       _configVersion(configVersion),
+      _configTerm(configTerm),
       _replicaSetId(id),
       _currentPrimaryIndex(currentPrimaryIndex),
       _currentSyncSourceIndex(currentSyncSourceIndex),
@@ -90,6 +93,13 @@ StatusWith<ReplSetMetadata> ReplSetMetadata::readFromMetadata(const BSONObj& met
     if (!status.isOK())
         return status;
 
+    // TODO(SERVER-47157): require configTerm.
+    long long configTerm;
+    status = bsonExtractIntegerFieldWithDefault(
+        replMetadataObj, kConfigTermFieldName, OpTime::kUninitializedTerm, &configTerm);
+    if (!status.isOK())
+        return status;
+
     OID id;
     status = bsonExtractOIDFieldWithDefault(replMetadataObj, kReplicaSetIdFieldName, OID(), &id);
     if (!status.isOK())
@@ -149,6 +159,7 @@ StatusWith<ReplSetMetadata> ReplSetMetadata::readFromMetadata(const BSONObj& met
                            lastOpCommitted,
                            lastOpVisible,
                            configVersion,
+                           configTerm,
                            id,
                            primaryIndex,
                            syncSourceIndex,
@@ -162,6 +173,7 @@ Status ReplSetMetadata::writeToMetadata(BSONObjBuilder* builder) const {
     replMetadataBuilder.appendDate(kLastCommittedWallFieldName, _lastOpCommitted.wallTime);
     _lastOpVisible.append(&replMetadataBuilder, kLastOpVisibleFieldName);
     replMetadataBuilder.append(kConfigVersionFieldName, _configVersion);
+    replMetadataBuilder.append(kConfigTermFieldName, _configTerm);
     replMetadataBuilder.append(kReplicaSetIdFieldName, _replicaSetId);
     replMetadataBuilder.append(kPrimaryIndexFieldName, _currentPrimaryIndex);
     replMetadataBuilder.append(kSyncSourceIndexFieldName, _currentSyncSourceIndex);
@@ -175,6 +187,7 @@ std::string ReplSetMetadata::toString() const {
     str::stream output;
     output << "ReplSetMetadata";
     output << " Config Version: " << _configVersion;
+    output << " Config Term: " << _configTerm;
     output << " Replicaset ID: " << _replicaSetId;
     output << " Term: " << _currentTerm;
     output << " Primary Index: " << _currentPrimaryIndex;
diff --git a/src/mongo/rpc/metadata/repl_set_metadata.h b/src/mongo/rpc/metadata/repl_set_metadata.h
index 02dc867701e..1a34493d967 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata.h
+++ b/src/mongo/rpc/metadata/repl_set_metadata.h
@@ -58,7 +58,8 @@ public:
                     repl::OpTimeAndWallTime committedOpTime,
                     repl::OpTime visibleOpTime,
                     long long configVersion,
-                    OID replicaSetId,
+                    long long configTerm,
+                    OID id,
                     int currentPrimaryIndex,
                     int currentSyncSourceIndex,
                     boost::optional<bool> isPrimary);
@@ -101,6 +102,13 @@ public:
     }
 
     /**
+     * Returns the ReplSetConfig term number of the sender.
+     */
+    long long getConfigTerm() const {
+        return _configTerm;
+    }
+
+    /**
      * Returns true if the sender has a replica set ID.
      */
     bool hasReplicaSetId() const {
@@ -157,6 +165,7 @@ private:
     repl::OpTime _lastOpVisible;
     long long _currentTerm = -1;
     long long _configVersion = -1;
+    long long _configTerm = repl::OpTime::kUninitializedTerm;
     OID _replicaSetId;
     // TODO(SERVER-47125): remove this member variable post-4.4.
     int _currentPrimaryIndex = kNoPrimary;
diff --git a/src/mongo/rpc/metadata/repl_set_metadata_test.cpp b/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
index ca89b0f7e64..7aa199fa046 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
+++ b/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
@@ -44,10 +44,10 @@ static const OpTime opTime(Timestamp(1234, 100), 5);
 static const OpTime opTime2(Timestamp(7777, 100), 6);
 static const Date_t committedWallTime = Date_t() + Seconds(opTime.getSecs());
 static const ReplSetMetadata metadata(
-    3, {opTime, committedWallTime}, opTime2, 6, OID("abcdefabcdefabcdefabcdef"), 12, -1, false);
+    3, {opTime, committedWallTime}, opTime2, 6, 0, OID("abcdefabcdefabcdefabcdef"), 12, -1, false);
 
 TEST(ReplResponseMetadataTest, ReplicaSetIdNotSet) {
-    ASSERT_FALSE(ReplSetMetadata(3, OpTimeAndWallTime(), OpTime(), 6, OID(), 12, -1, false)
+    ASSERT_FALSE(ReplSetMetadata(3, OpTimeAndWallTime(), OpTime(), 6, 0, OID(), 12, -1, false)
                      .hasReplicaSetId());
 }
 
@@ -60,14 +60,15 @@ TEST(ReplResponseMetadataTest, Roundtrip) {
     BSONObjBuilder builder;
     metadata.writeToMetadata(&builder).transitional_ignore();
 
-    BSONObj expectedObj(BSON(
-        kReplSetMetadataFieldName << BSON(
-            "term" << 3 << "lastOpCommitted"
-                   << BSON("ts" << opTime.getTimestamp() << "t" << opTime.getTerm())
-                   << "lastCommittedWall" << committedWallTime << "lastOpVisible"
-                   << BSON("ts" << opTime2.getTimestamp() << "t" << opTime2.getTerm())
-                   << "configVersion" << 6 << "replicaSetId" << metadata.getReplicaSetId()
-                   << "primaryIndex" << 12 << "syncSourceIndex" << -1 << "isPrimary" << false)));
+    BSONObj expectedObj(
+        BSON(kReplSetMetadataFieldName
+             << BSON("term" << 3 << "lastOpCommitted"
+                            << BSON("ts" << opTime.getTimestamp() << "t" << opTime.getTerm())
+                            << "lastCommittedWall" << committedWallTime << "lastOpVisible"
+                            << BSON("ts" << opTime2.getTimestamp() << "t" << opTime2.getTerm())
+                            << "configVersion" << 6 << "configTerm" << 0 << "replicaSetId"
+                            << metadata.getReplicaSetId() << "primaryIndex" << 12
+                            << "syncSourceIndex" << -1 << "isPrimary" << false)));
 
     BSONObj serializedObj = builder.obj();
     ASSERT_BSONOBJ_EQ(expectedObj, serializedObj);
@@ -80,6 +81,7 @@ TEST(ReplResponseMetadataTest, Roundtrip) {
     ASSERT_EQ(opTime2, clonedMetadata.getLastOpVisible());
     ASSERT_EQ(committedWallTime, clonedMetadata.getLastOpCommitted().wallTime);
     ASSERT_EQ(metadata.getConfigVersion(), clonedMetadata.getConfigVersion());
+    ASSERT_EQ(metadata.getConfigTerm(), clonedMetadata.getConfigTerm());
     ASSERT_EQ(metadata.getReplicaSetId(), clonedMetadata.getReplicaSetId());
 
     BSONObjBuilder clonedBuilder;
@@ -90,22 +92,24 @@ TEST(ReplResponseMetadataTest, Roundtrip) {
 }
 
 TEST(ReplResponseMetadataTest, MetadataCanBeConstructedWhenMissingOplogQueryMetadataFields) {
-    BSONObj obj(BSON(kReplSetMetadataFieldName
-                     << BSON("term" << 3 << "configVersion" << 6 << "replicaSetId"
-                                    << metadata.getReplicaSetId() << "lastCommittedWall"
-                                    << committedWallTime << "isPrimary" << false)));
+    BSONObj obj(BSON(kReplSetMetadataFieldName << BSON(
+                         "term" << 3 << "configVersion" << 6 << "configTerm" << 2 << "replicaSetId"
+                                << metadata.getReplicaSetId() << "lastCommittedWall"
+                                << committedWallTime << "isPrimary" << false)));
 
     auto status = ReplSetMetadata::readFromMetadata(obj);
     ASSERT_OK(status.getStatus());
 
     const auto& metadata = status.getValue();
     ASSERT_EQ(metadata.getConfigVersion(), 6);
+    ASSERT_EQ(metadata.getConfigTerm(), 2);
     ASSERT_EQ(metadata.getReplicaSetId(), metadata.getReplicaSetId());
     ASSERT_EQ(metadata.getTerm(), 3);
 }
 
-TEST(ReplResponseMetadataTest, MetadataCanBeConstructedWhenMissingIsPrimary) {
-    // TODO(SERVER-47125): delete this test in 4.6 when we can rely on the isPrimary field.
+TEST(ReplResponseMetadataTest, MetadataCanBeConstructedFrom42) {
+    // TODO(SERVER-47125): delete this test in 4.6 when we can rely on the isPrimary and configTerm
+    // fields.
     BSONObj obj(
         BSON(kReplSetMetadataFieldName
              << BSON("term" << 3 << "lastOpCommitted"
@@ -120,6 +124,7 @@ TEST(ReplResponseMetadataTest, MetadataCanBeConstructedWhenMissingIsPrimary) {
 
     const auto& metadata = status.getValue();
     ASSERT_FALSE(metadata.getIsPrimary().is_initialized());
+    ASSERT_EQUALS(metadata.getConfigTerm(), -1);
 }
 
 }  // unnamed namespace