Add cleanup functions to multiple DB backends. (#2313)

Ensure it's called on unmount, not just for seal.

builtin/logical/cassandra/backend.go

@@ -30,6 +30,10 @@ func Backend() *backend {
 		Secrets: []*framework.Secret{
 			secretCreds(&b),
 		},
+
+		Clean: func() {
+			b.ResetDB(nil)
+		},
 	}
 
 	return &b

builtin/logical/mssql/backend.go

@@ -31,6 +31,8 @@ func Backend() *backend {
 		Secrets: []*framework.Secret{
 			secretCreds(&b),
 		},
+
+		Clean: b.ResetDB,
 	}
 
 	return &b

builtin/logical/mysql/backend.go

@@ -31,6 +31,8 @@ func Backend() *backend {
 		Secrets: []*framework.Secret{
 			secretCreds(&b),
 		},
+
+		Clean: b.ResetDB,
 	}
 
 	return &b

vault/mount.go

@@ -256,6 +256,12 @@ func (c *Core) unmount(path string) (bool, error) {
 		return true, err
 	}
 
+	// Call cleanup function if it exists
+	b, ok := c.router.root.Get(path)
+	if ok {
+		b.(*routeEntry).backend.Cleanup()
+	}
+
 	// Unmount the backend entirely
 	if err := c.router.Unmount(path); err != nil {
 		return true, err
@@ -271,7 +277,7 @@ func (c *Core) unmount(path string) (bool, error) {
 		return true, err
 	}
 	if c.logger.IsInfo() {
-		c.logger.Info("core: successful unmounted", "path", path)
+		c.logger.Info("core: successfully unmounted", "path", path)
 	}
 	return true, nil
 }