Storage engine changes

Author: ewoutp

service/database_features.go

@@ -0,0 +1,54 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+// Author Ewout Prangsma
+//
+
+package service
+
+import driver "github.com/arangodb/go-driver"
+
+// DatabaseFeatures provides information about the features provided by the
+// database in a given version.
+type DatabaseFeatures driver.Version
+
+const (
+	v32 driver.Version = "3.2.0"
+	v34 driver.Version = "3.4.0"
+)
+
+// NewDatabaseFeatures returns a new DatabaseFeatures based on
+// the given version.
+func NewDatabaseFeatures(version driver.Version) DatabaseFeatures {
+	return DatabaseFeatures(version)
+}
+
+// HasStorageEngineOption returns true when `server.storage-engine`
+// option is supported.
+func (v DatabaseFeatures) HasStorageEngineOption() bool {
+	return driver.Version(v).CompareTo(v32) >= 0
+}
+
+// DefaultStorageEngine returns the default storage engine (mmfiles|rocksdb).
+func (v DatabaseFeatures) DefaultStorageEngine() string {
+	if driver.Version(v).CompareTo(v34) >= 0 {
+		return "rocksdb"
+	}
+	return "mmfiles"
+}