resolver.go

/*
Copyright 2018 The Kubernetes Authors.

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 endpoints

import (
	"encoding/json"
	"fmt"
	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/alicloud/alibaba-cloud-sdk-go/sdk/errors"
	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/alicloud/alibaba-cloud-sdk-go/sdk/requests"
	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/alicloud/alibaba-cloud-sdk-go/sdk/responses"
	"sync"
)

const (
	// ResolveEndpointUserGuideLink returns guide link
	ResolveEndpointUserGuideLink = ""
)

var once sync.Once
var resolvers []Resolver

// Resolver interface
type Resolver interface {
	TryResolve(param *ResolveParam) (endpoint string, support bool, err error)
}

// Resolve returns endpoint
func Resolve(param *ResolveParam) (endpoint string, err error) {
	supportedResolvers := getAllResolvers()
	for _, resolver := range supportedResolvers {
		endpoint, supported, err := resolver.TryResolve(param)
		if supported {
			return endpoint, err
		}
	}

	// not support
	errorMsg := fmt.Sprintf(errors.CanNotResolveEndpointErrorMessage, param, ResolveEndpointUserGuideLink)
	err = errors.NewClientError(errors.CanNotResolveEndpointErrorCode, errorMsg, nil)
	return
}

func getAllResolvers() []Resolver {
	once.Do(func() {
		resolvers = []Resolver{
			&SimpleHostResolver{},
			&MappingResolver{},
			&LocationResolver{},
			&LocalRegionalResolver{},
			&LocalGlobalResolver{},
		}
	})
	return resolvers
}

// ResolveParam params to resolve endpoint
type ResolveParam struct {
	Domain               string
	Product              string
	RegionId             string
	LocationProduct      string
	LocationEndpointType string
	CommonApi            func(request *requests.CommonRequest) (response *responses.CommonResponse, err error) `json:"-"`
}

// String returns json string
func (param *ResolveParam) String() string {
	jsonBytes, err := json.Marshal(param)
	if err != nil {
		return fmt.Sprint("ResolveParam.String() process error:", err)
	}
	return string(jsonBytes)
}