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Hyperledger Fabric2. Some basic concepts of X (1)

2022-07-06 04:59:00 【JasonCeng_】

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Hello everyone , I'm a Chuang , This is my number 30 Original articles .

I prefer reading ,2021 My reading volume in the whole year is about 20+ This book , Covering law 、 philosophy 、 technology 、 The humanities .

But the reading volume will feel , Simply reading is actually avoiding , So I decided to sort out my reading and thinking , Write something helpful for everyone .

Recently, I have been thinking about my core competitiveness , I found that we still need to focus on the field of Technology , After a period of groping , Decide to focus on in the near future Fabric Source code , Write a series of articles .

Although there are many interpretations on the Internet Fabric Source blog , But I hope to write something different . I once listened to teacher Zhang Yu's class , He introduced Mr. Hua Luogeng Once said a sentence ：“ Count without intuition , It's hard to be subtle when there are few forms .”

I agree with this sentence very much , Therefore, I also want to dare to use charts and words to express my thoughts , Hope for you , It helps me .

This series will use Hyperledger Fabric2.x Analysis based on series .

Fabric The first article of source code interpretation , Titled ：《Hyperledger Fabric2.x One of some basic concepts of （ One ）》, This paper mainly introduces transaction 、 block Two concepts .

transaction （Transaction）

transaction （Transaction, Or transaction ） yes Fabric Core concept of , It usually refers to calling chain code （ Intelligent contract ） An operation to change the ledger status data .

The change of ledger status is described by the transaction result read-write set , Gather transactions through Orderer The nodes are sorted and packed into blocks according to rules .

（1） Ordinary transaction messages encapsulate the execution transaction results of changing the ledger status , It needs to be sorted and packaged into blocks .

（2） The configuration transaction message is used to create a new application channel or update the channel configuration , It is usually packaged into blocks after sorting , At the same time, update the latest configured block number to the latest block metadata to facilitate index search .

block （Block）

block （Block） Refers to a collection of transactions that occur over a period of time , After sorting, package according to rules and add signatures 、 Hash value 、 Data structure composed of timestamp and other metadata .

Blockchain is a chained data structure based on blocks and connected in chronological order .

Fabric Block structure in （Block type ） Including the block head Header、 Transaction data set Data And block metadata Metadata Three parts .

（1） Block head Header Encapsulated block number 、 Hash value of the previous block 、 Hash value of current block

（2） Transaction data set Data Encapsulates the packaged transaction set

（3） Block metadata Metadata Encapsulated as follows 4 Metadata index entries ：

BlockMetadataIndex_SIGNATURES： Block signature ;
BlockMetadataIndex_LAST_CONFIG： Block number of the latest configured block ;
BlockMetadataIndex_TRANSACTIONS_FILTER： Latest transaction filter , Encapsulates the transaction data set Data Transaction verification code corresponding to all transactions in , Identify the validity of their transactions .
BlockMetadataIndex_ORDERER:Orderer Configuration information , Such as Kafka Initialization parameters of consensus component .

actually , The real block data structure is much more complex than the above figure , The right of this article should be a good introduction , Lay the foundation for the in-depth introduction later .

Release here Fabric Code of block data structure ：github.com/hyperledger/fabric-protos-go/common/common.pb.go

// This is finalized block structure to be shared among the orderer and peer
// Note that the BlockHeader chains to the previous BlockHeader, and the BlockData hash is embedded
// in the BlockHeader.  This makes it natural and obvious that the Data is included in the hash, but
// the Metadata is not.
type Block struct {
   Header               *BlockHeader   `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
   Data                 *BlockData     `protobuf:"bytes,2,opt,name=data,proto3" json:"data,omitempty"`
   Metadata             *BlockMetadata `protobuf:"bytes,3,opt,name=metadata,proto3" json:"metadata,omitempty"`
   XXX_NoUnkeyedLiteral struct{}       `json:"-"`
   XXX_unrecognized     []byte         `json:"-"`
   XXX_sizecache        int32          `json:"-"`
}

We look forward to working together in the future fabric In depth analysis of block data structure , It's like peeling an onion , Step by step , from the shallower to the deeper

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