Book Image

Blockchain with Hyperledger Fabric - Second Edition

By : Nitin Gaur, Anthony O'Dowd, Petr Novotny, Luc Desrosiers, Venkatraman Ramakrishna, Salman A. Baset
Book Image

Blockchain with Hyperledger Fabric - Second Edition

By: Nitin Gaur, Anthony O'Dowd, Petr Novotny, Luc Desrosiers, Venkatraman Ramakrishna, Salman A. Baset

Overview of this book

Blockchain with Hyperledger Fabric - Second Edition is a refreshed and extended version of the successful book on practical Hyperledger Fabric blockchain development. This edition includes many new chapters, alongside comprehensive updates and additions to the existing ones. Entirely reworked for Hyperledger Fabric version 2, this edition will bring you right up to date with the latest in blockchain. Using a real-world Trade Finance and Logistics example, with working code available on GitHub, you’ll really understand both how and why Hyperledger Fabric can be used to maximum effect. This book is your comprehensive guide and reference to explore and build blockchain networks using Hyperledger Fabric version 2. This edition of the book begins by outlining the evolution of blockchain, including an overview of relevant blockchain technologies. Starting from first principles, you’ll learn how to design and operate a permissioned blockchain network based on Hyperledger Fabric version 2. You will learn how to configure the main architectural components of a permissioned blockchain network including Peers, Orderers, Certificate Authorities, Channels, and Policies. You’ll then learn how to design, develop, package, and deploy smart contracts, and how they are subsequently used by applications. This edition also contains chapters on DevOps, blockchain governance, and security, making this your go-to book for Hyperledger Fabric version 2.
Table of Contents (18 chapters)
16
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17
Index

Transaction mechanisms

In the following two sections, we will discuss the two key transaction mechanisms related to contract design and implementation, specifically the ReadSet and WriteSet structures used to record information into transactions and the multiversion concurrency control used to ensure consistency between transactions.

The ReadSet and WriteSet

On receipt of a transaction invocation message from a client, the endorsing peer executes a transaction. The execution invokes the contract in the context of the peer's Worldstate and records all reads and writes of its data on the ledger into a ReadSet and WriteSet.

The transaction's WriteSet contains a list of key and value pairs that were modified during the execution by the contract. When the value of a key is modified by a putState function (that is, a new key and value are recorded or an existing key is updated with a new value), the WriteSet will contain the updated key and value pair.

When a...