lib/go-atscfg/parentabstraction.go - trafficcontrol - Git at Google

 package atscfg

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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.
  */

 import (
 	"errors"
 	"strconv"
 	"strings"
 )

 // ParentAbstraction contains all the data necessary to build either parent.config or strategies.yaml.
 type ParentAbstraction struct {
 	Services []*ParentAbstractionService
 	// Peers is the list of peer proxy caches to be used in a strategy peering group.
 	// a cache will only have one set of peers for potential use in all delivery services.
 	Peers []*ParentAbstractionServiceParent
 }

 // ParentAbstractionService represents a single delivery service's parent data.
 // For parent.config, this becomes a single dest_domain= line.
 // For strategies, this becomes a strategy along with its corresponding groups and hosts.
 type ParentAbstractionService struct {
 	// Name is a unique name for the service.
 	// It can be anything unique, but should probably be the Traffic ops Delivery Service name.
 	Name string
 	// Comment is a text comment about the service, not including the comment syntax (e.g. # or //).
 	// Should be empty if !opt.AddComments.
 	Comment string
 	// DestDomain is the FQDN of the remap.config target.
 	// Becomes parent.config dest_domain directive
 	// Becomes strategies.yaml TODO
 	DestDomain string

 	// Port is the port of the remap.config target,
 	// which MUST be valid, and is implicitly 80 for http targets and 443 for https targets.
 	// Becomes parent.config port directive
 	// Becomes strategies.yaml TODO
 	Port int

 	// Parents is the list of parents, either parent proxy caches or origins.
 	// This is a sorted array. Parents will be inserted into the config file in the order they appear.
 	// Becomes parent.config parent= directive members
 	// Becomes strategies.yaml TODO
 	Parents []*ParentAbstractionServiceParent

 	// Parents is the list of secondary parents, either parent proxy caches or origins,
 	// to be used if the primary parents fail. See SecondaryMode.
 	// Becomes parent.config secondary_parent= directive members
 	// Becomes strategies.yaml TODO
 	SecondaryParents []*ParentAbstractionServiceParent

 	// SecondaryMode is how to try SecondaryParents if primary Parents fail.
 	// Becomes parent.config secondary_mode directive
 	// Becomes strategies.yaml TODO
 	SecondaryMode ParentAbstractionServiceParentSecondaryMode

 	// CachePeerResult is used only when the RetryPolicy is set to
 	// 'consistent_hash' and the SecondaryMode is set to 'peering'.
 	// In the case that it's used and set to 'true', query results
 	// from peer caches will not be cached locally.
 	CachePeerResult bool

 	// GoDirect is whether to go direct to parents via normal HTTP requests.
 	// False means to make proxy requests to the parents.
 	// Becomes parent.config go_direct and parent_is_proxy directives
 	// Becomes strategies.yaml TODO
 	GoDirect bool

 	// IgnoreQueryStringInParentSelection is whether to use the query string of the request
 	// when selecting a parent, e.g. via Consistent Hash.
 	// Becomes parent.config qstring directive
 	// Becomes strategies.yaml TODO
 	IgnoreQueryStringInParentSelection bool

 	// MarkdownResponseCodes is the list of HTTP response codes from the parent
 	// to consider as errors and mark the parent as unhealthy. Typically 5xx codes.
 	// Becomes parent.config unavailable_server_retry_responses directive
 	// Becomes strategies.yaml TODO
 	MarkdownResponseCodes []int

 	// ErrorResponseCodes is the list of HTTP response codes from the parent
 	// to consider as errors, but NOT mark the parent unhealthy. Typically 4xx codes.
 	// Becomes parent.config unavailable_server_retry_responses directive
 	// Becomes strategies.yaml TODO
 	ErrorResponseCodes []int

 	// MaxSimpleRetries is the maximum number of non-markdown errors to attempt
 	// before returning the error to the client. See ErrorResponseCodes
 	// Becomes parent.config max_simple_retries
 	// Becomes strategies.yaml TODO
 	MaxSimpleRetries int

 	// MaxMarkdownRetries is the maximum number of markdown errors to attempt
 	// before returning the error to the client. See MarkdownResponseCodes
 	// Becomes parent.config max_unavailable_server_retries
 	// Becomes strategies.yaml TODO
 	MaxMarkdownRetries int

 	// RetryPolicy is how to retry primary versus secondary parents.
 	// Becomes parent.config round_robin directive
 	// Becomes strategies.yaml TODO
 	RetryPolicy ParentAbstractionServiceRetryPolicy

 	// Weight is the weight of this parent relative to other parents in consistent hash (and potentially other non-sequential) parent selection. The default is 0.999
 	// Becomes parent.config weight directive
 	// Becomes strategies.yaml TODO
 	Weight float64
 }

 // ParentAbstractionServices implements sort.Interface
 type ParentAbstractionServices []*ParentAbstractionService

 func (ps ParentAbstractionServices) Len() int      { return len(ps) }
 func (ps ParentAbstractionServices) Swap(i, j int) { ps[i], ps[j] = ps[j], ps[i] }
 func (ps ParentAbstractionServices) Less(i, j int) bool {
 	if ps[i].DestDomain != ps[j].DestDomain {
 		return ps[i].DestDomain < ps[j].DestDomain
 	}
 	return ps[i].Port < ps[j].Port
 }

 type ParentAbstractionServiceParentSecondaryMode string

 const ParentAbstractionServiceParentSecondaryModeExhaust = ParentAbstractionServiceParentSecondaryMode("exhaust")
 const ParentAbstractionServiceParentSecondaryModeAlternate = ParentAbstractionServiceParentSecondaryMode("alternate")
 const ParentAbstractionServiceParentSecondaryModePeering = ParentAbstractionServiceParentSecondaryMode("peering")
 const ParentAbstractionServiceParentSecondaryModeInvalid = ParentAbstractionServiceParentSecondaryMode("")

 const ParentAbstractionServiceParentSecondaryModeDefault = ParentAbstractionServiceParentSecondaryModeAlternate

 // ToParentDotConfigVal returns the ATS parent.config secondary_mode= value for the enum.
 // If the mode is invalid, ParentAbstractionServiceParentSecondaryModeDefault is returned without error.
 func (mo ParentAbstractionServiceParentSecondaryMode) ToParentDotConfigVal() string {
 	switch mo {
 	case ParentAbstractionServiceParentSecondaryModeExhaust:
 		return "2"
 	case ParentAbstractionServiceParentSecondaryModeAlternate:
 		return "1"
 	default:
 		return ParentAbstractionServiceParentSecondaryModeDefault.ToParentDotConfigVal()
 	}
 }

 type ParentAbstractionServiceRetryPolicy string

 const ParentAbstractionServiceRetryPolicyRoundRobinIP = ParentAbstractionServiceRetryPolicy("round_robin_ip")
 const ParentAbstractionServiceRetryPolicyRoundRobinStrict = ParentAbstractionServiceRetryPolicy("round_robin_strict")
 const ParentAbstractionServiceRetryPolicyFirst = ParentAbstractionServiceRetryPolicy("first")
 const ParentAbstractionServiceRetryPolicyLatched = ParentAbstractionServiceRetryPolicy("latched")
 const ParentAbstractionServiceRetryPolicyConsistentHash = ParentAbstractionServiceRetryPolicy("consistent_hash")
 const ParentAbstractionServiceRetryPolicyInvalid = ParentAbstractionServiceRetryPolicy("")

 const DefaultParentAbstractionServiceRetryPolicy = ParentAbstractionServiceRetryPolicyConsistentHash

 func ParentSelectAlgorithmToParentAbstractionServiceRetryPolicy(alg string) ParentAbstractionServiceRetryPolicy {
 	switch strings.TrimSpace(strings.ToLower(alg)) {
 	case "true":
 		return ParentAbstractionServiceRetryPolicyRoundRobinIP
 	case "strict":
 		return ParentAbstractionServiceRetryPolicyRoundRobinStrict
 	case "false":
 		return ParentAbstractionServiceRetryPolicyFirst
 	case "consistent_hash":
 		return ParentAbstractionServiceRetryPolicyConsistentHash
 	case "latched":
 		return ParentAbstractionServiceRetryPolicyLatched
 	default:
 		return ParentAbstractionServiceRetryPolicyInvalid
 	}
 }

 // ToParentDotConfigFormat returns the ATS parent.config round_robin= value for the policy.
 // If the policy is invalid, the default is returned without error.
 func (po ParentAbstractionServiceRetryPolicy) ToParentDotConfigFormat() string {
 	switch po {
 	case ParentAbstractionServiceRetryPolicyRoundRobinIP:
 		return "true"
 	case ParentAbstractionServiceRetryPolicyRoundRobinStrict:
 		return "strict"
 	case ParentAbstractionServiceRetryPolicyFirst:
 		return "false"
 	case ParentAbstractionServiceRetryPolicyLatched:
 		return "latched"
 	case ParentAbstractionServiceRetryPolicyConsistentHash:
 		return "consistent_hash"
 	default:
 		return "consistent_hash"
 	}
 }

 // ParentSelectParamQStringHandlingToBool returns whether the param is to use the query string in the parent select algorithm or not.
 // If the parameter value is not valid, returns nil.
 func ParentSelectParamQStringHandlingToBool(paramVal string) *bool {
 	switch strings.TrimSpace(strings.ToLower(paramVal)) {
 	case "consider":
 		v := true
 		return &v
 	case "ignore":
 		v := false
 		return &v
 	}
 	return nil
 }

 type ParentAbstractionServiceParent struct {
 	// FQDN is the parent FQDN that ATS will use. Note this may be an IP.
 	FQDN   string
 	Port   int
 	Weight float64
 }

 // Key returns a unique key that can be used to compare parents for equality.
 func (sp ParentAbstractionServiceParent) Key() string {
 	return sp.FQDN + ":" + strconv.Itoa(sp.Port)
 }

 func RemoveParentDuplicates(inputs []*ParentAbstractionServiceParent, seens map[string]struct{}) ([]*ParentAbstractionServiceParent, map[string]struct{}) {
 	if seens == nil {
 		seens = make(map[string]struct{})
 	}
 	uniques := []*ParentAbstractionServiceParent{}
 	for _, input := range inputs {
 		key := input.Key()
 		if _, ok := seens[key]; !ok {
 			uniques = append(uniques, input)
 			seens[key] = struct{}{}
 		}
 	}
 	return uniques, seens
 }

 func ParseRetryResponses(resp string) ([]int, error) {
 	resp = strings.TrimSpace(resp)
 	if len(resp) > 2 && resp[0] == '"' {
 		resp = resp[1 : len(resp)-1]
 	}
 	codes := []int{}
 	codeStrs := strings.Split(resp, ",")
 	for _, codeStr := range codeStrs {
 		codeStr = strings.TrimSpace(codeStr)
 		if codeStr == "" {
 			continue
 		}
 		code, err := strconv.Atoi(codeStr)
 		if err != nil {
 			return nil, errors.New("malformed")
 		}
 		codes = append(codes, code)
 	}
 	return codes, nil
 }

 var DefaultSimpleRetryCodes = []int{404}
 var DefaultUnavailableServerRetryCodes = []int{503}

 const DefaultIgnoreQueryStringInParentSelection = false

 func parentAbstractionToParentDotConfig(pa *ParentAbstraction, opt *ParentConfigOpts, atsMajorVersion int) (string, []string, error) {
 	warnings := []string{}
 	txt := ""

 	// parent.config dest_domain directives must be unique.
 	// This is the "duplicate origin problem"
 	processedOriginsToDSNames := map[string]string{}

 	for _, svc := range pa.Services {
 		if existingDS, ok := processedOriginsToDSNames[svc.DestDomain]; ok {
 			warnings = append(warnings, "duplicate origin! DS '"+svc.Name+"' and '"+existingDS+"' share origin '"+svc.DestDomain+"': skipping '"+svc.Name+"'!")
 			continue
 		}

 		svcLine, svcWarns, err := svc.ToParentDotConfigLine(opt, atsMajorVersion)
 		warnings = append(warnings, svcWarns...)
 		if err != nil {
 			// TODO add DS name
 			// TODO don't error? No single delivery service should be able to break others.
 			return "", warnings, errors.New("creating parent.config line from service: " + err.Error())
 		}
 		txt += svcLine + "\n"

 		processedOriginsToDSNames[svc.DestDomain] = svc.Name
 	}
 	return txt, warnings, nil
 }

 func (svc *ParentAbstractionService) ToParentDotConfigLine(opt *ParentConfigOpts, atsMajorVersion int) (string, []string, error) {
 	warnings := []string{}
 	txt := ""
 	if opt.AddComments && svc.Comment != "" {
 		txt += LineCommentParentDotConfig + " " + svc.Comment + "\n"
 	}
 	txt += `dest_domain=` + svc.DestDomain
 	if svc.Port != 0 {
 		txt += ` port=` + strconv.Itoa(svc.Port)
 	}

 	if atsMajorVersion >= 6 && svc.RetryPolicy == ParentAbstractionServiceRetryPolicyConsistentHash && len(svc.SecondaryParents) > 0 {
 		// TODO add quotes
 		if len(svc.Parents) > 0 {
 			txt += ` parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(svc.Parents) + `"`
 		}
 		if len(svc.SecondaryParents) > 0 {
 			txt += ` secondary_parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(svc.SecondaryParents) + `"`
 		}
 		txt += ` secondary_mode=` + svc.SecondaryMode.ToParentDotConfigVal()
 	} else {
 		parents := []*ParentAbstractionServiceParent{}
 		for _, pa := range svc.Parents {
 			parents = append(parents, pa)
 		}
 		for _, pa := range svc.SecondaryParents {
 			parents = append(parents, pa)
 		}
 		if len(parents) > 0 {
 			txt += ` parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(parents) + `"`
 		}
 	}

 	txt += ` round_robin=` + svc.RetryPolicy.ToParentDotConfigFormat()
 	txt += ` go_direct=` + strconv.FormatBool(svc.GoDirect)
 	txt += ` qstring=`
 	if !svc.IgnoreQueryStringInParentSelection {
 		txt += `consider`
 	} else {
 		txt += `ignore`
 	}
 	txt += ` parent_is_proxy=` + strconv.FormatBool(!svc.GoDirect)

 	if svc.MaxSimpleRetries > 0 && svc.MaxMarkdownRetries > 0 {
 		txt += ` parent_retry=both`
 	} else if svc.MaxSimpleRetries > 0 {
 		txt += ` parent_retry=simple_retry`
 	} else if svc.MaxMarkdownRetries > 0 {
 		txt += ` parent_retry=unavailable_server_retry`
 	}

 	if svc.MaxSimpleRetries > 0 {
 		txt += ` max_simple_retries=` + strconv.Itoa(svc.MaxSimpleRetries)
 	}
 	if svc.MaxMarkdownRetries > 0 {
 		txt += ` max_unavailable_server_retries=` + strconv.Itoa(svc.MaxMarkdownRetries)
 	}

 	if len(svc.ErrorResponseCodes) > 0 {
 		if atsMajorVersion >= 9 {
 			txt += ` simple_server_retry_responses="` + strings.Join(intsToStrs(svc.ErrorResponseCodes), `,`) + `"`
 		} else {
 			warnings = append(warnings, "Service '"+svc.Name+"' had simple retry codes '"+strings.Join(intsToStrs(svc.ErrorResponseCodes), ",")+"' but ATS version "+strconv.Itoa(atsMajorVersion)+" < 9 does not support custom simple retry codes, omitting!")
 		}
 	}

 	if len(svc.MarkdownResponseCodes) > 0 {
 		txt += ` unavailable_server_retry_responses="` + strings.Join(intsToStrs(svc.MarkdownResponseCodes), `,`) + `"`
 	}

 	// 	txt += ` unavailable_server_retry_responses=` + unavailableServerRetryResponses

 	return txt, warnings, nil
 }

 func intsToStrs(is []int) []string {
 	strs := []string{}
 	for _, i := range is {
 		strs = append(strs, strconv.Itoa(i))
 	}
 	return strs
 }

 func (pa *ParentAbstractionServiceParent) ToParentDotConfigFormat() string {
 	return pa.FQDN + ":" + strconv.Itoa(pa.Port) + "|" + strconv.FormatFloat(pa.Weight, 'f', -1, 64)
 }

 const ParentDotConfigParentSeparator = `;`

 func ParentAbstractionServiceParentsToParentDotConfigLine(parents []*ParentAbstractionServiceParent) string {
 	parentStrs := []string{}
 	for _, parent := range parents {
 		parentStrs = append(parentStrs, parent.ToParentDotConfigFormat())
 	}
 	return strings.Join(parentStrs, ParentDotConfigParentSeparator)
 }
	package atscfg

	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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.
	*/

	import (
	"errors"
	"strconv"
	"strings"
	)

	// ParentAbstraction contains all the data necessary to build either parent.config or strategies.yaml.
	type ParentAbstraction struct {
	Services []*ParentAbstractionService
	// Peers is the list of peer proxy caches to be used in a strategy peering group.
	// a cache will only have one set of peers for potential use in all delivery services.
	Peers []*ParentAbstractionServiceParent
	}

	// ParentAbstractionService represents a single delivery service's parent data.
	// For parent.config, this becomes a single dest_domain= line.
	// For strategies, this becomes a strategy along with its corresponding groups and hosts.
	type ParentAbstractionService struct {
	// Name is a unique name for the service.
	// It can be anything unique, but should probably be the Traffic ops Delivery Service name.
	Name string
	// Comment is a text comment about the service, not including the comment syntax (e.g. # or //).
	// Should be empty if !opt.AddComments.
	Comment string
	// DestDomain is the FQDN of the remap.config target.
	// Becomes parent.config dest_domain directive
	// Becomes strategies.yaml TODO
	DestDomain string

	// Port is the port of the remap.config target,
	// which MUST be valid, and is implicitly 80 for http targets and 443 for https targets.
	// Becomes parent.config port directive
	// Becomes strategies.yaml TODO
	Port int

	// Parents is the list of parents, either parent proxy caches or origins.
	// This is a sorted array. Parents will be inserted into the config file in the order they appear.
	// Becomes parent.config parent= directive members
	// Becomes strategies.yaml TODO
	Parents []*ParentAbstractionServiceParent

	// Parents is the list of secondary parents, either parent proxy caches or origins,
	// to be used if the primary parents fail. See SecondaryMode.
	// Becomes parent.config secondary_parent= directive members
	// Becomes strategies.yaml TODO
	SecondaryParents []*ParentAbstractionServiceParent

	// SecondaryMode is how to try SecondaryParents if primary Parents fail.
	// Becomes parent.config secondary_mode directive
	// Becomes strategies.yaml TODO
	SecondaryMode ParentAbstractionServiceParentSecondaryMode

	// CachePeerResult is used only when the RetryPolicy is set to
	// 'consistent_hash' and the SecondaryMode is set to 'peering'.
	// In the case that it's used and set to 'true', query results
	// from peer caches will not be cached locally.
	CachePeerResult bool

	// GoDirect is whether to go direct to parents via normal HTTP requests.
	// False means to make proxy requests to the parents.
	// Becomes parent.config go_direct and parent_is_proxy directives
	// Becomes strategies.yaml TODO
	GoDirect bool

	// IgnoreQueryStringInParentSelection is whether to use the query string of the request
	// when selecting a parent, e.g. via Consistent Hash.
	// Becomes parent.config qstring directive
	// Becomes strategies.yaml TODO
	IgnoreQueryStringInParentSelection bool

	// MarkdownResponseCodes is the list of HTTP response codes from the parent
	// to consider as errors and mark the parent as unhealthy. Typically 5xx codes.
	// Becomes parent.config unavailable_server_retry_responses directive
	// Becomes strategies.yaml TODO
	MarkdownResponseCodes []int

	// ErrorResponseCodes is the list of HTTP response codes from the parent
	// to consider as errors, but NOT mark the parent unhealthy. Typically 4xx codes.
	// Becomes parent.config unavailable_server_retry_responses directive
	// Becomes strategies.yaml TODO
	ErrorResponseCodes []int

	// MaxSimpleRetries is the maximum number of non-markdown errors to attempt
	// before returning the error to the client. See ErrorResponseCodes
	// Becomes parent.config max_simple_retries
	// Becomes strategies.yaml TODO
	MaxSimpleRetries int

	// MaxMarkdownRetries is the maximum number of markdown errors to attempt
	// before returning the error to the client. See MarkdownResponseCodes
	// Becomes parent.config max_unavailable_server_retries
	// Becomes strategies.yaml TODO
	MaxMarkdownRetries int

	// RetryPolicy is how to retry primary versus secondary parents.
	// Becomes parent.config round_robin directive
	// Becomes strategies.yaml TODO
	RetryPolicy ParentAbstractionServiceRetryPolicy

	// Weight is the weight of this parent relative to other parents in consistent hash (and potentially other non-sequential) parent selection. The default is 0.999
	// Becomes parent.config weight directive
	// Becomes strategies.yaml TODO
	Weight float64
	}

	// ParentAbstractionServices implements sort.Interface
	type ParentAbstractionServices []*ParentAbstractionService

	func (ps ParentAbstractionServices) Len() int { return len(ps) }
	func (ps ParentAbstractionServices) Swap(i, j int) { ps[i], ps[j] = ps[j], ps[i] }
	func (ps ParentAbstractionServices) Less(i, j int) bool {
	if ps[i].DestDomain != ps[j].DestDomain {
	return ps[i].DestDomain < ps[j].DestDomain
	}
	return ps[i].Port < ps[j].Port
	}

	type ParentAbstractionServiceParentSecondaryMode string

	const ParentAbstractionServiceParentSecondaryModeExhaust = ParentAbstractionServiceParentSecondaryMode("exhaust")
	const ParentAbstractionServiceParentSecondaryModeAlternate = ParentAbstractionServiceParentSecondaryMode("alternate")
	const ParentAbstractionServiceParentSecondaryModePeering = ParentAbstractionServiceParentSecondaryMode("peering")
	const ParentAbstractionServiceParentSecondaryModeInvalid = ParentAbstractionServiceParentSecondaryMode("")

	const ParentAbstractionServiceParentSecondaryModeDefault = ParentAbstractionServiceParentSecondaryModeAlternate

	// ToParentDotConfigVal returns the ATS parent.config secondary_mode= value for the enum.
	// If the mode is invalid, ParentAbstractionServiceParentSecondaryModeDefault is returned without error.
	func (mo ParentAbstractionServiceParentSecondaryMode) ToParentDotConfigVal() string {
	switch mo {
	case ParentAbstractionServiceParentSecondaryModeExhaust:
	return "2"
	case ParentAbstractionServiceParentSecondaryModeAlternate:
	return "1"
	default:
	return ParentAbstractionServiceParentSecondaryModeDefault.ToParentDotConfigVal()
	}
	}

	type ParentAbstractionServiceRetryPolicy string

	const ParentAbstractionServiceRetryPolicyRoundRobinIP = ParentAbstractionServiceRetryPolicy("round_robin_ip")
	const ParentAbstractionServiceRetryPolicyRoundRobinStrict = ParentAbstractionServiceRetryPolicy("round_robin_strict")
	const ParentAbstractionServiceRetryPolicyFirst = ParentAbstractionServiceRetryPolicy("first")
	const ParentAbstractionServiceRetryPolicyLatched = ParentAbstractionServiceRetryPolicy("latched")
	const ParentAbstractionServiceRetryPolicyConsistentHash = ParentAbstractionServiceRetryPolicy("consistent_hash")
	const ParentAbstractionServiceRetryPolicyInvalid = ParentAbstractionServiceRetryPolicy("")

	const DefaultParentAbstractionServiceRetryPolicy = ParentAbstractionServiceRetryPolicyConsistentHash

	func ParentSelectAlgorithmToParentAbstractionServiceRetryPolicy(alg string) ParentAbstractionServiceRetryPolicy {
	switch strings.TrimSpace(strings.ToLower(alg)) {
	case "true":
	return ParentAbstractionServiceRetryPolicyRoundRobinIP
	case "strict":
	return ParentAbstractionServiceRetryPolicyRoundRobinStrict
	case "false":
	return ParentAbstractionServiceRetryPolicyFirst
	case "consistent_hash":
	return ParentAbstractionServiceRetryPolicyConsistentHash
	case "latched":
	return ParentAbstractionServiceRetryPolicyLatched
	default:
	return ParentAbstractionServiceRetryPolicyInvalid
	}
	}

	// ToParentDotConfigFormat returns the ATS parent.config round_robin= value for the policy.
	// If the policy is invalid, the default is returned without error.
	func (po ParentAbstractionServiceRetryPolicy) ToParentDotConfigFormat() string {
	switch po {
	case ParentAbstractionServiceRetryPolicyRoundRobinIP:
	return "true"
	case ParentAbstractionServiceRetryPolicyRoundRobinStrict:
	return "strict"
	case ParentAbstractionServiceRetryPolicyFirst:
	return "false"
	case ParentAbstractionServiceRetryPolicyLatched:
	return "latched"
	case ParentAbstractionServiceRetryPolicyConsistentHash:
	return "consistent_hash"
	default:
	return "consistent_hash"
	}
	}

	// ParentSelectParamQStringHandlingToBool returns whether the param is to use the query string in the parent select algorithm or not.
	// If the parameter value is not valid, returns nil.
	func ParentSelectParamQStringHandlingToBool(paramVal string) *bool {
	switch strings.TrimSpace(strings.ToLower(paramVal)) {
	case "consider":
	v := true
	return &v
	case "ignore":
	v := false
	return &v
	}
	return nil
	}

	type ParentAbstractionServiceParent struct {
	// FQDN is the parent FQDN that ATS will use. Note this may be an IP.
	FQDN string
	Port int
	Weight float64
	}

	// Key returns a unique key that can be used to compare parents for equality.
	func (sp ParentAbstractionServiceParent) Key() string {
	return sp.FQDN + ":" + strconv.Itoa(sp.Port)
	}

	func RemoveParentDuplicates(inputs []ParentAbstractionServiceParent, seens map[string]struct{}) ([]ParentAbstractionServiceParent, map[string]struct{}) {
	if seens == nil {
	seens = make(map[string]struct{})
	}
	uniques := []*ParentAbstractionServiceParent{}
	for _, input := range inputs {
	key := input.Key()
	if _, ok := seens[key]; !ok {
	uniques = append(uniques, input)
	seens[key] = struct{}{}
	}
	}
	return uniques, seens
	}

	func ParseRetryResponses(resp string) ([]int, error) {
	resp = strings.TrimSpace(resp)
	if len(resp) > 2 && resp[0] == '"' {
	resp = resp[1 : len(resp)-1]
	}
	codes := []int{}
	codeStrs := strings.Split(resp, ",")
	for _, codeStr := range codeStrs {
	codeStr = strings.TrimSpace(codeStr)
	if codeStr == "" {
	continue
	}
	code, err := strconv.Atoi(codeStr)
	if err != nil {
	return nil, errors.New("malformed")
	}
	codes = append(codes, code)
	}
	return codes, nil
	}

	var DefaultSimpleRetryCodes = []int{404}
	var DefaultUnavailableServerRetryCodes = []int{503}

	const DefaultIgnoreQueryStringInParentSelection = false

	func parentAbstractionToParentDotConfig(pa ParentAbstraction, opt ParentConfigOpts, atsMajorVersion int) (string, []string, error) {
	warnings := []string{}
	txt := ""

	// parent.config dest_domain directives must be unique.
	// This is the "duplicate origin problem"
	processedOriginsToDSNames := map[string]string{}

	for _, svc := range pa.Services {
	if existingDS, ok := processedOriginsToDSNames[svc.DestDomain]; ok {
	warnings = append(warnings, "duplicate origin! DS '"+svc.Name+"' and '"+existingDS+"' share origin '"+svc.DestDomain+"': skipping '"+svc.Name+"'!")
	continue
	}

	svcLine, svcWarns, err := svc.ToParentDotConfigLine(opt, atsMajorVersion)
	warnings = append(warnings, svcWarns...)
	if err != nil {
	// TODO add DS name
	// TODO don't error? No single delivery service should be able to break others.
	return "", warnings, errors.New("creating parent.config line from service: " + err.Error())
	}
	txt += svcLine + "\n"

	processedOriginsToDSNames[svc.DestDomain] = svc.Name
	}
	return txt, warnings, nil
	}

	func (svc ParentAbstractionService) ToParentDotConfigLine(opt ParentConfigOpts, atsMajorVersion int) (string, []string, error) {
	warnings := []string{}
	txt := ""
	if opt.AddComments && svc.Comment != "" {
	txt += LineCommentParentDotConfig + " " + svc.Comment + "\n"
	}
	txt += `dest_domain=` + svc.DestDomain
	if svc.Port != 0 {
	txt += ` port=` + strconv.Itoa(svc.Port)
	}

	if atsMajorVersion >= 6 && svc.RetryPolicy == ParentAbstractionServiceRetryPolicyConsistentHash && len(svc.SecondaryParents) > 0 {
	// TODO add quotes
	if len(svc.Parents) > 0 {
	txt += ` parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(svc.Parents) + `"`
	}
	if len(svc.SecondaryParents) > 0 {
	txt += ` secondary_parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(svc.SecondaryParents) + `"`
	}
	txt += ` secondary_mode=` + svc.SecondaryMode.ToParentDotConfigVal()
	} else {
	parents := []*ParentAbstractionServiceParent{}
	for _, pa := range svc.Parents {
	parents = append(parents, pa)
	}
	for _, pa := range svc.SecondaryParents {
	parents = append(parents, pa)
	}
	if len(parents) > 0 {
	txt += ` parent="` + ParentAbstractionServiceParentsToParentDotConfigLine(parents) + `"`
	}
	}

	txt += ` round_robin=` + svc.RetryPolicy.ToParentDotConfigFormat()
	txt += ` go_direct=` + strconv.FormatBool(svc.GoDirect)
	txt += ` qstring=`
	if !svc.IgnoreQueryStringInParentSelection {
	txt += `consider`
	} else {
	txt += `ignore`
	}
	txt += ` parent_is_proxy=` + strconv.FormatBool(!svc.GoDirect)

	if svc.MaxSimpleRetries > 0 && svc.MaxMarkdownRetries > 0 {
	txt += ` parent_retry=both`
	} else if svc.MaxSimpleRetries > 0 {
	txt += ` parent_retry=simple_retry`
	} else if svc.MaxMarkdownRetries > 0 {
	txt += ` parent_retry=unavailable_server_retry`
	}

	if svc.MaxSimpleRetries > 0 {
	txt += ` max_simple_retries=` + strconv.Itoa(svc.MaxSimpleRetries)
	}
	if svc.MaxMarkdownRetries > 0 {
	txt += ` max_unavailable_server_retries=` + strconv.Itoa(svc.MaxMarkdownRetries)
	}

	if len(svc.ErrorResponseCodes) > 0 {
	if atsMajorVersion >= 9 {
	txt += ` simple_server_retry_responses="` + strings.Join(intsToStrs(svc.ErrorResponseCodes), `,`) + `"`
	} else {
	warnings = append(warnings, "Service '"+svc.Name+"' had simple retry codes '"+strings.Join(intsToStrs(svc.ErrorResponseCodes), ",")+"' but ATS version "+strconv.Itoa(atsMajorVersion)+" < 9 does not support custom simple retry codes, omitting!")
	}
	}

	if len(svc.MarkdownResponseCodes) > 0 {
	txt += ` unavailable_server_retry_responses="` + strings.Join(intsToStrs(svc.MarkdownResponseCodes), `,`) + `"`
	}

	// txt += ` unavailable_server_retry_responses=` + unavailableServerRetryResponses

	return txt, warnings, nil
	}

	func intsToStrs(is []int) []string {
	strs := []string{}
	for _, i := range is {
	strs = append(strs, strconv.Itoa(i))
	}
	return strs
	}

	func (pa *ParentAbstractionServiceParent) ToParentDotConfigFormat() string {
	return pa.FQDN + ":" + strconv.Itoa(pa.Port) + "\|" + strconv.FormatFloat(pa.Weight, 'f', -1, 64)
	}

	const ParentDotConfigParentSeparator = `;`

	func ParentAbstractionServiceParentsToParentDotConfigLine(parents []*ParentAbstractionServiceParent) string {
	parentStrs := []string{}
	for _, parent := range parents {
	parentStrs = append(parentStrs, parent.ToParentDotConfigFormat())
	}
	return strings.Join(parentStrs, ParentDotConfigParentSeparator)
	}