SERVER-43272 Implement getDatabaseInfos method (listDatabases) in DBClient

3 files changed, 103 insertions, 0 deletions

diff --git a/src/mongo/client/dbclient_base.cpp b/src/mongo/client/dbclient_base.cpp
index 2633a560298..7af010fa6b8 100644
--- a/src/mongo/client/dbclient_base.cpp
+++ b/src/mongo/client/dbclient_base.cpp
@@ -588,6 +588,42 @@ list<BSONObj> DBClientBase::getCollectionInfos(const string& db, const BSONObj&
     uasserted(18630, str::stream() << "listCollections failed: " << res);
 }
 
+vector<BSONObj> DBClientBase::getDatabaseInfos(const BSONObj& filter,
+                                               const bool nameOnly,
+                                               const bool authorizedDatabases) {
+    vector<BSONObj> infos;
+
+    BSONObjBuilder bob;
+    bob.append("listDatabases", 1);
+    bob.append("filter", filter);
+
+    if (nameOnly) {
+        bob.append("nameOnly", 1);
+    }
+    if (authorizedDatabases) {
+        bob.append("authorizedDatabases", 1);
+    }
+
+    BSONObj cmd = bob.done();
+
+    BSONObj res;
+    if (runCommand("admin", cmd, res, QueryOption_SlaveOk)) {
+        BSONObj dbs = res["databases"].Obj();
+        BSONObjIterator it(dbs);
+        while (it.more()) {
+            BSONElement e = it.next();
+            infos.push_back(e.Obj().getOwned());
+        }
+
+        return infos;
+    }
+
+    uassertStatusOKWithContext(getStatusFromCommandResult(res),
+                               str::stream()
+                                   << "Command 'listDatabases' failed. Full command: " << cmd);
+    MONGO_UNREACHABLE;
+}
+
 bool DBClientBase::exists(const string& ns) {
     BSONObj filter = BSON("name" << nsToCollectionSubstring(ns));
     list<BSONObj> results = getCollectionInfos(nsToDatabase(ns), filter);
diff --git a/src/mongo/client/dbclient_base.h b/src/mongo/client/dbclient_base.h
index 13d0d50cc99..eb24295c5b6 100644
--- a/src/mongo/client/dbclient_base.h
+++ b/src/mongo/client/dbclient_base.h
@@ -462,6 +462,16 @@ public:
      */
     std::list<BSONObj> getCollectionInfos(const std::string& db, const BSONObj& filter = BSONObj());
 
+    /**
+     * Lists databases available on the server.
+     * @param filter A filter for the results
+     * @param nameOnly Only return the names of the databases
+     * @param authorizedDatabases Only return the databases the user is authorized on
+     */
+    std::vector<BSONObj> getDatabaseInfos(const BSONObj& filter = BSONObj(),
+                                          const bool nameOnly = false,
+                                          const bool authorizedDatabases = false);
+
     bool exists(const std::string& ns);
 
     /** Create an index on the collection 'ns' as described by the given keys. If you wish
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 22cd9256808..97e8ee011db 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -1822,6 +1822,61 @@ public:
     }
 };
 
+class GetDatabaseInfosTest : public CollectionBase {
+public:
+    GetDatabaseInfosTest() : CollectionBase("GetDatabaseInfosTest") {}
+
+    void run() {
+        const char* ns1 = "unittestsdb1.querytests.coll1";
+        {
+            Lock::GlobalWrite lk(&_opCtx);
+            OldClientContext context(&_opCtx, ns1);
+            WriteUnitOfWork wunit(&_opCtx);
+            context.db()->createCollection(&_opCtx, NamespaceString(ns1));
+            wunit.commit();
+        }
+        insert(ns1, BSON("a" << 1));
+        auto dbInfos = _client.getDatabaseInfos(BSONObj(), true /*nameOnly*/);
+        checkNewDBInResults(dbInfos, 1);
+
+
+        const char* ns2 = "unittestsdb2.querytests.coll2";
+        {
+            Lock::GlobalWrite lk(&_opCtx);
+            OldClientContext context(&_opCtx, ns2);
+            WriteUnitOfWork wunit(&_opCtx);
+            context.db()->createCollection(&_opCtx, NamespaceString(ns2));
+            wunit.commit();
+        }
+        insert(ns2, BSON("b" << 2));
+        dbInfos = _client.getDatabaseInfos(BSONObj(), true /*nameOnly*/);
+        checkNewDBInResults(dbInfos, 2);
+
+
+        const char* ns3 = "unittestsdb3.querytests.coll3";
+        {
+            Lock::GlobalWrite lk(&_opCtx);
+            OldClientContext context(&_opCtx, ns3);
+            WriteUnitOfWork wunit(&_opCtx);
+            context.db()->createCollection(&_opCtx, NamespaceString(ns3));
+            wunit.commit();
+        }
+        insert(ns3, BSON("c" << 3));
+        dbInfos = _client.getDatabaseInfos(BSONObj(), true /*nameOnly*/);
+        checkNewDBInResults(dbInfos, 3);
+    }
+
+    void checkNewDBInResults(const std::vector<BSONObj> results, const int dbNum) {
+        std::string target = "unittestsdb" + std::to_string(dbNum);
+        for (auto res : results) {
+            if (res["name"].str() == target) {
+                return;
+            }
+        }
+        ASSERT(false);  // Should not hit this unless we failed to find the database.
+    }
+};
+
 class CollectionInternalBase : public CollectionBase {
 public:
     CollectionInternalBase(const char* nsLeaf)
@@ -1985,6 +2040,8 @@ public:
         add<WhatsMyUri>();
         add<QueryByUuid>();
         add<GetIndexSpecsByUUID>();
+        add<CountByUUID>();
+        add<GetDatabaseInfosTest>();
         add<Exhaust>();
         add<QueryReadsAll>();
         add<queryobjecttests::names1>();