Fabric 1.0源代码笔记 之 policy（背书策略）

1、policy概述

policy代码分布在core/policy、core/policyprovider、common/policies目录下。目录结构如下：

• core/policy/policy.go，PolicyChecker接口定义及实现、PolicyCheckerFactory接口定义。
• core/policyprovider/provider.go，PolicyChecker工厂默认实现。
• common/policies目录
  ???? policy.go，ChannelPolicyManagerGetter接口及实现。
  ???? implicitmeta_util.go，通道策略工具函数。

2、PolicyChecker工厂

2.1、PolicyCheckerFactory接口定义

type PolicyCheckerFactory interface {
????NewPolicyChecker() PolicyChecker //构造PolicyChecker实例
}

var pcFactory PolicyCheckerFactory //全局变量定义及赋值函数
func RegisterPolicyCheckerFactory(f PolicyCheckerFactory) {
????pcFactory = f
}
//代码在core/policy/policy.go

2.2、PolicyCheckerFactory接口默认实现

type defaultFactory struct{}

//构造policy.PolicyChecker
func (f *defaultFactory) NewPolicyChecker() policy.PolicyChecker {
????return policy.NewPolicyChecker(
????????peer.NewChannelPolicyManagerGetter(), //&channelPolicyManagerGetter{}
????????mgmt.GetLocalMSP(),
????????mgmt.NewLocalMSPPrincipalGetter(),
????)
}

//获取policy.PolicyChecker，即调用policy.GetPolicyChecker()
func GetPolicyChecker() policy.PolicyChecker

func init() { //初始化全局变量pcFactory
????policy.RegisterPolicyCheckerFactory(&defaultFactory{})
}

3、PolicyChecker接口定义及实现

3.1、PolicyChecker接口定义

type PolicyChecker interface {
????CheckPolicy(channelID, policyName string, signedProp *pb.SignedProposal) error
????CheckPolicyBySignedData(channelID, policyName string, sd []*common.SignedData) error
????CheckPolicyNoChannel(policyName string, signedProp *pb.SignedProposal) error
}
//代码在core/policy/policy.go

3.2、PolicyChecker接口实现

PolicyChecker接口实现，即policyChecker结构体及方法。

type policyChecker struct {
????channelPolicyManagerGetter policies.ChannelPolicyManagerGetter //通道策略管理器
????localMSP                   msp.IdentityDeserializer //身份
????principalGetter            mgmt.MSPPrincipalGetter //委托人
}

//构造policyChecker
func NewPolicyChecker(channelPolicyManagerGetter policies.ChannelPolicyManagerGetter, localMSP msp.IdentityDeserializer, principalGetter mgmt.MSPPrincipalGetter) PolicyChecker
//检查签名提案是否符合通道策略
func (p *policyChecker) CheckPolicy(channelID, policyName string, signedProp *pb.SignedProposal) error
func (p *policyChecker) CheckPolicyNoChannel(policyName string, signedProp *pb.SignedProposal) error
//检查签名数据是否符合通道策略，获取策略并调取policy.Evaluate(sd)
func (p *policyChecker) CheckPolicyBySignedData(channelID, policyName string, sd []*common.SignedData) error
func GetPolicyChecker() PolicyChecker //pcFactory.NewPolicyChecker()
//代码在core/policy/policy.go

func (p policyChecker) CheckPolicy(channelID, policyName string, signedProp pb.SignedProposal) error代码如下：

func (p *policyChecker) CheckPolicy(channelID, policyName string, signedProp *pb.SignedProposal) error {
????if channelID == "" { //channelID为空，调取CheckPolicyNoChannel()
????????return p.CheckPolicyNoChannel(policyName, signedProp)
????}
????
????policyManager, _ := p.channelPolicyManagerGetter.Manager(channelID)
????proposal, err := utils.GetProposal(signedProp.ProposalBytes) //获取proposal
????header, err := utils.GetHeader(proposal.Header)
????shdr, err := utils.GetSignatureHeader(header.SignatureHeader) //SignatureHeader
????sd := []*common.SignedData{&common.SignedData{
????????Data:      signedProp.ProposalBytes,
????????Identity:  shdr.Creator,
????????Signature: signedProp.Signature,
????}}
????return p.CheckPolicyBySignedData(channelID, policyName, sd)
}
//代码在core/policy/policy.go

4、ChannelPolicyManagerGetter接口及实现

4.1、ChannelPolicyManagerGetter接口定义

type ChannelPolicyManagerGetter interface {
????Manager(channelID string) (Manager, bool)
}
//代码在common/policies/policy.go

4.2、ChannelPolicyManagerGetter接口实现

ChannelPolicyManagerGetter接口实现，即ManagerImpl结构体及方法。

type ManagerImpl struct {
????parent        *ManagerImpl
????basePath      string
????fqPrefix      string
????providers     map[int32]Provider //type Provider interface
????config        *policyConfig //type policyConfig struct
????pendingConfig map[interface{}]*policyConfig //type policyConfig struct
????pendingLock   sync.RWMutex
????SuppressSanityLogMessages bool
}

type Provider interface {
????NewPolicy(data []byte) (Policy, proto.Message, error)
}

type policyConfig struct {
????policies map[string]Policy //type Policy interface
????managers map[string]*ManagerImpl
????imps     []*implicitMetaPolicy
}

type Policy interface {
????//对给定的签名数据，按规则检验确认是否符合约定的条件
????Evaluate(signatureSet []*cb.SignedData) error
}

//构造ManagerImpl
func NewManagerImpl(basePath string, providers map[int32]Provider) *ManagerImpl
//获取pm.basePath
func (pm *ManagerImpl) BasePath() string
//获取pm.config.policies，即map[string]Policy中Key列表
func (pm *ManagerImpl) PolicyNames() []string
//获取指定路径的子管理器
func (pm *ManagerImpl) Manager(path []string) (Manager, bool)
//获取pm.config.policies[relpath]
//获取Policy
func (pm *ManagerImpl) GetPolicy(id string) (Policy, bool)
func (pm *ManagerImpl) BeginPolicyProposals(tx interface{}, groups []string) ([]Proposer, error)
func (pm *ManagerImpl) RollbackProposals(tx interface{})
func (pm *ManagerImpl) PreCommit(tx interface{}) error
func (pm *ManagerImpl) CommitProposals(tx interface{})
func (pm *ManagerImpl) ProposePolicy(tx interface{}, key string, configPolicy *cb.ConfigPolicy) (proto.Message, error)
//代码在common/policies/policy.go

type implicitMetaPolicy struct {
????conf        *cb.ImplicitMetaPolicy
????threshold   int
????subPolicies []Policy
}
//代码在common/policies/implicitmeta.go

5、通道策略工具函数

type ImplicitMetaPolicy_Rule int32
const (
????ImplicitMetaPolicy_ANY      ImplicitMetaPolicy_Rule = 0 //任意
????ImplicitMetaPolicy_ALL      ImplicitMetaPolicy_Rule = 1 //所有
????ImplicitMetaPolicy_MAJORITY ImplicitMetaPolicy_Rule = 2 //大多数
)
//代码在protos/common/policies.pb.go

//构造cb.Policy
func ImplicitMetaPolicyWithSubPolicy(subPolicyName string, rule cb.ImplicitMetaPolicy_Rule) *cb.ConfigPolicy
func TemplateImplicitMetaPolicyWithSubPolicy(path []string, policyName string, subPolicyName string, rule cb.ImplicitMetaPolicy_Rule) *cb.ConfigGroup

//调取TemplateImplicitMetaPolicyWithSubPolicy(path, policyName, policyName, rule)
func TemplateImplicitMetaPolicy(path []string, policyName string, rule cb.ImplicitMetaPolicy_Rule) *cb.ConfigGroup

//任意，TemplateImplicitMetaPolicy(path, policyName, cb.ImplicitMetaPolicy_ANY)
func TemplateImplicitMetaAnyPolicy(path []string, policyName string) *cb.ConfigGroup

//所有，TemplateImplicitMetaPolicy(path, policyName, cb.ImplicitMetaPolicy_ALL)
func TemplateImplicitMetaAllPolicy(path []string, policyName string) *cb.ConfigGroup

//大多数，TemplateImplicitMetaPolicy(path, policyName, cb.ImplicitMetaPolicy_MAJORITY)
func TemplateImplicitMetaMajorityPolicy(path []string, policyName string) *cb.ConfigGroup
//代码在common/policies/implicitmeta_util.go

区块链教程Fabric1.0源代码分析policy（背书策略

原文：http://blog.51cto.com/14041296/2313968