Fabric 1.0源代码分析(11)consenter（共识插件） #filter（过滤器）
# Fabric 1.0源代码笔记 之 consenter（共识插件） #filter（过滤器）
## 1、filter概述
filter代码分布在orderer/common/filter、orderer/common/configtxfilter、orderer/common/sizefilter、orderer/common/sigfilter、orderer/multichain目录下。
orderer/common/filter/filter.go，Rule接口定义及emptyRejectRule和acceptRule实现，Committer接口定义及noopCommitter实现，RuleSet结构体及方法。
orderer/common/configtxfilter目录，configFilter结构体（实现Rule接口）及configCommitter结构体（实现Committer接口）。
orderer/common/sizefilter目录，maxBytesRule结构体（实现Rule接口）。
orderer/multichain/chainsupport.go，filter工具函数。
orderer/multichain/systemchain.go，systemChainFilter结构体（实现Rule接口）及systemChainCommitter结构体（实现Committer接口）。
## 2、Rule接口定义及实现
### 2.1、Rule接口定义
```go
type
Action
int
const (
Accept =
iota
Reject
Forward
)
type
Rule
interface {
//定义一个过滤器函数, 它接受、拒绝或转发 (到下一条规则) 一个信封
Apply(message *ab.Envelope) (Action, Committer)
}
//代码在orderer/common/filter/filter.go
```
### 2.2、emptyRejectRule（校验是否为空过滤器）
```go
type
emptyRejectRule
struct{}
var EmptyRejectRule = Rule(emptyRejectRule{})
func (a emptyRejectRule) Apply(message *ab.Envelope) (Action, Committer) {
if message.Payload ==
nil {
return Reject,
nil
}
return Forward,
nil
}
//代码在orderer/common/filter/filter.go
```
### 2.3、acceptRule（接受过滤器）
```go
type
acceptRule
struct{}
var AcceptRule = Rule(acceptRule{})
func (a acceptRule) Apply(message *ab.Envelope) (Action, Committer) {
return Accept, NoopCommitter
}
//代码在orderer/common/filter/filter.go
```
### 2.4、configFilter（配置交易合法性过滤器）
```go
type
configFilter
struct {
configManager api.Manager
}
func NewFilter(manager api.Manager) filter.Rule
//构造configFilter
//配置交易过滤器
func (cf *configFilter) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
msgData, err := utils.UnmarshalPayload(message.Payload)
//获取Payload
chdr, err := utils.UnmarshalChannelHeader(msgData.Header.ChannelHeader)
//获取ChannelHeader
if chdr.Type != int32(cb.HeaderType_CONFIG) {
//配置交易
return filter.Forward,
nil
}
configEnvelope, err := configtx.UnmarshalConfigEnvelope(msgData.Data)
//获取configEnvelope
err = cf.configManager.Validate(configEnvelope)
//校验configEnvelope
return filter.Accept, &configCommitter{
manager: cf.configManager,
configEnvelope: configEnvelope,
}
}
//代码在orderer/common/configtxfilter/filter.go
```
### 2.5、sizefilter（交易大小过滤器）
```go
type
maxBytesRule
struct {
support Support
}
func MaxBytesRule(support Support) filter.Rule
//构造maxBytesRule
func (r *maxBytesRule) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
maxBytes := r.support.BatchSize().AbsoluteMaxBytes
if size := messageByteSize(message); size > maxBytes {
return filter.Reject,
nil
}
return filter.Forward,
nil
}
//代码在orderer/common/sizefilter/sizefilter.go
```
### 2.6、sigFilter（签名数据校验过滤器）
```go
type
sigFilter
struct {
policySource
string
policyManager policies.Manager
}
func New(policySource
string, policyManager policies.Manager) filter.Rule
//构造sigFilter
func (sf *sigFilter) Apply(message *cb.Envelope) (filter.Action, filter.Committer) {
signedData, err := message.AsSignedData()
//构造SignedData
policy, ok := sf.policyManager.GetPolicy(sf.policySource)
//获取策略
err = policy.Evaluate(signedData)
//校验策略
if err ==
nil {
return filter.Forward,
nil
}
return filter.Reject,
nil
}
//代码在orderer/common/sigfilter/sigfilter.go
```
### 2.7、systemChainFilter（系统链过滤器）
```go
type
systemChainFilter
struct {
cc chainCreator
support limitedSupport
}
func newSystemChainFilter(ls limitedSupport, cc chainCreator) filter.Rule
//构造systemChainFilter
func (scf *systemChainFilter) Apply(env *cb.Envelope) (filter.Action, filter.Committer) {
msgData := &cb.Payload{}
err := proto.Unmarshal(env.Payload, msgData)
//获取Payload
chdr, err := utils.UnmarshalChannelHeader(msgData.Header.ChannelHeader)
if chdr.Type != int32(cb.HeaderType_ORDERER_TRANSACTION) {
//ORDERER_TRANSACTION
return filter.Forward,
nil
}
maxChannels := scf.support.SharedConfig().MaxChannelsCount()
if maxChannels >
0 {
if uint64(scf.cc.channelsCount()) > maxChannels {
return filter.Reject,
nil
}
}
configTx := &cb.Envelope{}
err = proto.Unmarshal(msgData.Data, configTx)
err = scf.authorizeAndInspect(configTx)
return filter.Accept, &systemChainCommitter{
filter: scf,
configTx: configTx,
}
}
//代码在orderer/multichain/systemchain.go
```
## 3、Committer接口定义及实现
### 3.1、Committer接口定义
```go
type
Committer
interface {
Commit()
//提交
Isolated()
bool
//判断交易是孤立的块，或与其他交易混合的块
}
//代码在orderer/common/filter/filter.go
```
### 3.2、noopCommitter
```go
type
noopCommitter
struct{}
var NoopCommitter = Committer(noopCommitter{})
func (nc noopCommitter) Commit() {}
func (nc noopCommitter) Isolated()
bool {
return
false }
//代码在orderer/common/filter/filter.go
```
### 3.3、configCommitter
```go
type
configCommitter
struct {
manager api.Manager
configEnvelope *cb.ConfigEnvelope
}
func (cc *configCommitter) Commit() {
err := cc.manager.Apply(cc.configEnvelope)
}
func (cc *configCommitter) Isolated()
bool {
return
true
}
//代码在orderer/common/configtxfilter/filter.go
```
### 3.4、systemChainCommitter
```go
type
systemChainCommitter
struct {
filter *systemChainFilter
configTx *cb.Envelope
}
func (scc *systemChainCommitter) Isolated()
bool {
return
true
}
func (scc *systemChainCommitter) Commit() {
scc.filter.cc.newChain(scc.configTx)
}
//代码在orderer/multichain/systemchain.go
```
### 4、RuleSet结构体及方法
```go
type
RuleSet
struct {
rules []Rule
}
func NewRuleSet(rules []Rule) *RuleSet
//构造RuleSet
func (rs *RuleSet) Apply(message *ab.Envelope) (Committer,
error) {
for _, rule :=
range rs.rules {
action, committer := rule.Apply(message)
switch action {
case Accept:
//接受
return committer,
nil
case Reject:
//拒绝
return
nil, fmt.Errorf(
"Rejected by rule: %T", rule)
default:
}
}
return
nil, fmt.Errorf(
"No matching filter found")
}
//代码在orderer/common/filter/filter.go
```
### 5、filter工具函数
```go
//为普通 (非系统) 链创建过滤器集
func createStandardFilters(ledgerResources *ledgerResources) *filter.RuleSet {
return filter.NewRuleSet([]filter.Rule{
filter.EmptyRejectRule,
//EmptyRejectRule
sizefilter.MaxBytesRule(ledgerResources.SharedConfig()),
//sizefilter
sigfilter.New(policies.ChannelWriters, ledgerResources.PolicyManager()),
//sigfilter
configtxfilter.NewFilter(ledgerResources),
//configtxfilter
filter.AcceptRule,
//AcceptRule
})
}
//为系统链创建过滤器集
func createSystemChainFilters(ml *multiLedger, ledgerResources *ledgerResources) *filter.RuleSet {
return filter.NewRuleSet([]filter.Rule{
filter.EmptyRejectRule,
//EmptyRejectRule
sizefilter.MaxBytesRule(ledgerResources.SharedConfig()),
//sizefilter
sigfilter.New(policies.ChannelWriters, ledgerResources.PolicyManager()),
//sigfilter
newSystemChainFilter(ledgerResources, ml),
configtxfilter.NewFilter(ledgerResources),
//configtxfilter
filter.AcceptRule,
//AcceptRule
})
}
//代码在orderer/multichain/chainsupport.go
```
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