2 files changed, 82 insertions, 1 deletions

diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
index e05eb3fccd1..4d438701e24 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
@@ -167,7 +167,40 @@ namespace {
 
     StatusWith<DatabaseType> CatalogManagerReplicaSet::getDatabase(const std::string& dbName) {
         invariant(nsIsDbOnly(dbName));
-        return notYetImplemented;
+
+        // The two databases that are hosted on the config server are config and admin
+        if (dbName == "config" || dbName == "admin") {
+            DatabaseType dbt;
+            dbt.setName(dbName);
+            dbt.setSharded(false);
+            dbt.setPrimary("config");
+
+            return dbt;
+        }
+
+        const auto& configShard = grid.shardRegistry()->findIfExists("config");
+        const auto readHost = configShard->getTargeter()->findHost(kConfigReadSelector);
+        if (!readHost.isOK()) {
+            return readHost.getStatus();
+        }
+
+        auto findStatus = _find(readHost.getValue(),
+                                NamespaceString(DatabaseType::ConfigNS),
+                                BSON(DatabaseType::name(dbName)),
+                                1);
+        if (!findStatus.isOK()) {
+            return findStatus.getStatus();
+        }
+
+        const auto& docs = findStatus.getValue();
+        if (docs.empty()) {
+            return {ErrorCodes::NamespaceNotFound,
+                    stream() << "database " << dbName << " not found"};
+        }
+
+        invariant(docs.size() == 1);
+
+        return DatabaseType::fromBSON(docs.front());
     }
 
     Status CatalogManagerReplicaSet::updateCollection(const std::string& collNs,
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
index e5229aba2e1..4d35495ce51 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
@@ -39,6 +39,7 @@
 #include "mongo/s/catalog/replset/catalog_manager_replica_set.h"
 #include "mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h"
 #include "mongo/s/catalog/type_collection.h"
+#include "mongo/s/catalog/type_database.h"
 #include "mongo/s/client/shard_registry.h"
 #include "mongo/util/log.h"
 
@@ -103,5 +104,52 @@ namespace {
         future.get();
     }
 
+    TEST_F(CatalogManagerReplSetTestFixture, GetDatabaseExisting) {
+        RemoteCommandTargeterMock* targeter =
+            RemoteCommandTargeterMock::get(shardRegistry()->findIfExists("config")->getTargeter());
+        targeter->setFindHostReturnValue(HostAndPort("TestHost1"));
+
+        DatabaseType expectedDb;
+        expectedDb.setName("bigdata");
+        expectedDb.setPrimary("shard0000");
+        expectedDb.setSharded(true);
+
+        auto future = async(std::launch::async, [this, &expectedDb] {
+            return assertGet(catalogManager()->getDatabase(expectedDb.getName()));
+        });
+
+        onFindCommand([&expectedDb](const std::string& dbName, const BSONObj& cmdObj) {
+            const NamespaceString nss(dbName + '.' + cmdObj.firstElement().String());
+            ASSERT_EQ(nss.toString(), DatabaseType::ConfigNS);
+
+            auto query = assertGet(LiteParsedQuery::fromFindCommand(nss, cmdObj, false));
+
+            ASSERT_EQ(query->ns(), DatabaseType::ConfigNS);
+            ASSERT_EQ(query->getFilter(), BSON(DatabaseType::name(expectedDb.getName())));
+
+            return vector<BSONObj>{ expectedDb.toBSON() };
+        });
+
+        const auto& actualDb = future.get();
+        ASSERT_EQ(expectedDb.toBSON(), actualDb.toBSON());
+    }
+
+    TEST_F(CatalogManagerReplSetTestFixture, GetDatabaseNotExisting) {
+        RemoteCommandTargeterMock* targeter =
+            RemoteCommandTargeterMock::get(shardRegistry()->findIfExists("config")->getTargeter());
+        targeter->setFindHostReturnValue(HostAndPort("TestHost1"));
+
+        auto future = async(std::launch::async, [this] {
+            auto dbResult = catalogManager()->getDatabase("NonExistent");
+            ASSERT_EQ(dbResult.getStatus(), ErrorCodes::NamespaceNotFound);
+        });
+
+        onFindCommand([](const std::string& dbName, const BSONObj& cmdObj) {
+            return vector<BSONObj>{ };
+        });
+
+        future.get();
+    }
+
 } // namespace
 } // namespace mongo