docker/swarmkit

package manager

import (
    "fmt"
    "reflect"

    "github.com/moby/swarmkit/v2/api"
    "github.com/moby/swarmkit/v2/manager/state/store"
)

// IsStateDirty returns true if any objects have been added to raft which make
// the state "dirty". Currently, the existence of any object other than the
// default cluster or the local node implies a dirty state.
func (m *Manager) IsStateDirty() (bool, error) {
    var (
        storeSnapshot *api.StoreSnapshot
        err           error
    )
    m.raftNode.MemoryStore().View(func(readTx store.ReadTx) {
        storeSnapshot, err = m.raftNode.MemoryStore().Save(readTx)
    })

    if err != nil {
        return false, err
    }

    // Check Nodes and Clusters fields.
    nodeID := m.config.SecurityConfig.ClientTLSCreds.NodeID()
    if len(storeSnapshot.Nodes) > 1 || (len(storeSnapshot.Nodes) == 1 && storeSnapshot.Nodes[0].ID != nodeID) {
        return true, nil
    }

    clusterID := m.config.SecurityConfig.ClientTLSCreds.Organization()
    if len(storeSnapshot.Clusters) > 1 || (len(storeSnapshot.Clusters) == 1 && storeSnapshot.Clusters[0].ID != clusterID) {
        return true, nil
    }

    // Use reflection to check that other fields don't have values. This
    // lets us implement a whitelist-type approach, where we don't need to
    // remember to add individual types here.

    val := reflect.ValueOf(*storeSnapshot)
    numFields := val.NumField()

    for i := 0; i != numFields; i++ {
        field := val.Field(i)
        structField := val.Type().Field(i)
        if structField.Type.Kind() != reflect.Slice {
            panic(fmt.Sprintf("unexpected field type in StoreSnapshot: %s (type %v)", structField.Name, structField.Type.Kind()))
        }
        if structField.Name != "Nodes" && structField.Name != "Clusters" && structField.Name != "Networks" && field.Len() != 0 {
            // One of the other data types has an entry
            return true, nil
        }
    }

    return false, nil
}