vitess.io/vitess@v0.16.2/go/vt/vttablet/tabletmanager/events/state_change.go (about)

     1  /*
     2  Copyright 2019 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  // Package events contains event structs used by the tabletmanager package.
    18  package events
    19  
    20  import topodatapb "vitess.io/vitess/go/vt/proto/topodata"
    21  
    22  // StateChange is an event that describes state changes in the tablet as seen
    23  // by the TabletManager. It is triggered after the tablet has processed a state
    24  // change, which might have been initiated internally, or when the tablet
    25  // noticed that an external process modified its topo record.
    26  type StateChange struct {
    27  	// OldTablet is the topo record of the tablet before the change.
    28  	OldTablet topodatapb.Tablet
    29  	// NewTablet is the topo record representing the current state.
    30  	NewTablet topodatapb.Tablet
    31  	// Reason is an optional string that describes the source of the change.
    32  	Reason string
    33  }