Database refactor invalidate (#2566)

* WIP on invalidate function

* cassandraConnectionProducer has Close()

* Delete database from connections map on successful db.Close()

* Move clear connection into its own func

* Use const for database config path

builtin/logical/database/backend.go

@@ -12,6 +12,8 @@ import (
 	"github.com/hashicorp/vault/logical/framework"
 )
 
+const databaseConfigPath = "database/dbs/"
+
 func Factory(conf *logical.BackendConfig) (logical.Backend, error) {
 	return Backend(conf).Setup(conf)
 }
@@ -41,6 +43,8 @@ func Backend(conf *logical.BackendConfig) *databaseBackend {
 		},
 
 		Clean: b.closeAllDBs,
+
+		Invalidate: b.invalidate,
 	}
 
 	b.logger = conf.Logger
@@ -123,9 +127,32 @@ func (b *databaseBackend) Role(s logical.Storage, n string) (*roleEntry, error)
 	return &result, nil
 }
 
+func (b *databaseBackend) invalidate(key string) {
+	b.Lock()
+	defer b.Unlock()
+
+	switch {
+	case strings.HasPrefix(key, databaseConfigPath):
+		name := strings.TrimPrefix(key, databaseConfigPath)
+		b.clearConnection(name)
+	}
+}
+
+// clearConnection closes the database connection and
+// removes it from the b.connections map.
+func (b *databaseBackend) clearConnection(name string) {
+	db, ok := b.connections[name]
+	if ok {
+		db.Close()
+		delete(b.connections, name)
+	}
+}
+
 const backendHelp = `
-The PostgreSQL backend dynamically generates database users.
+The database backend supports using many different databases
+as secret backends, including but not limited to:
+cassandra, msslq, mysql, postgres
 
 After mounting this backend, configure it using the endpoints within
-the "config/" path.
+the "database/dbs/" path.
 `

builtin/logical/database/path_config_connection.go

@@ -40,13 +40,9 @@ func (b *databaseBackend) pathConnectionReset(req *logical.Request, data *framew
 	b.Lock()
 	defer b.Unlock()
 
-	db, ok := b.connections[name]
-	if ok {
-		db.Close()
-		delete(b.connections, name)
-	}
+	b.clearConnection(name)
 
-	db, err := b.getOrCreateDBObj(req.Storage, name)
+	_, err := b.getOrCreateDBObj(req.Storage, name)
 	if err != nil {
 		return nil, err
 	}