deploy/rook/pkg/daemon/multus/statemachine.go

/*
Copyright 2023 The Rook Authors. All rights reserved.

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.
*/

package multus

import (
	"context"
	"fmt"
	"time"

	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
)

type validationState interface {
	Run(ctx context.Context, vsm *validationStateMachine) (suggestions []string, err error)
}

type validationStateMachine struct {
	vt                *ValidationTest
	state             validationState
	timer             *time.Timer
	stateWasChanged   bool
	resourceOwnerRefs []meta.OwnerReference
	testResults       *ValidationTestResults
	lastSuggestions   []string
	lastErr           error
	done              bool
}

func (vsm *validationStateMachine) SetNextState(nextState validationState) {
	vsm.stateWasChanged = true
	vsm.state = nextState
}

func (vsm *validationStateMachine) Exit() {
	vsm.done = true
}

func (vsm *validationStateMachine) Run(ctx context.Context) (*ValidationTestResults, error) {
	vsm.timer = time.NewTimer(vsm.vt.ResourceTimeout)
	defer func() { vsm.timer.Stop() }()

	for {
		select {
		case <-ctx.Done():
			return vsm.exitContextCanceled(ctx)

		case <-vsm.timer.C:
			vsm.testResults.addSuggestions(vsm.lastSuggestions...)
			return vsm.testResults, fmt.Errorf("multus validation test timed out: %w", vsm.lastErr)

		default:
			// give each state the full resource timeout to run successfully
			if vsm.stateWasChanged {
				vsm.resetTimer()
				vsm.stateWasChanged = false
			}

			// run the state
			suggestions, err := vsm.state.Run(ctx, vsm)

			// if the context was canceled, the error message won't be as useful as gathered from
			// the last context, so exit before updating the latest suggestions and error
			if ctx.Err() != nil {
				return vsm.exitContextCanceled(ctx)
			}

			// record the latest suggestions and error
			vsm.lastErr = err
			vsm.lastSuggestions = suggestions

			// exit the state machine, error or not
			if vsm.done {
				vsm.testResults.addSuggestions(vsm.lastSuggestions...)
				if vsm.lastErr != nil {
					return vsm.testResults, fmt.Errorf("multus validation test failed: %w", vsm.lastErr)
				}
				return vsm.testResults, nil
			}
			if err != nil {
				vsm.vt.Logger.Infof("continuing: %s", err)
			}

			time.Sleep(2 * time.Second)
		}
	}
}

func (vsm *validationStateMachine) resetTimer() {
	if !vsm.timer.Stop() {
		<-vsm.timer.C
	}
	vsm.timer.Reset(vsm.vt.ResourceTimeout)
}

func (vsm *validationStateMachine) exitContextCanceled(ctx context.Context) (*ValidationTestResults, error) {
	vsm.testResults.addSuggestions(vsm.lastSuggestions...)
	return vsm.testResults, fmt.Errorf("context canceled before multus validation test could complete: %s: %w", ctx.Err().Error(), vsm.lastErr)
}