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
Another Book You May Enjoy
17
Index

Logging output

Logging is a vital part of system code, enabling the analysis and detection of runtime problems.

Logging in Fabric is based on the standard Go logging package, https://github.com/uber-go/zaph. The logging mechanism provides severity-based control of logs and pretty-printing decoration of messages. The logging levels are defined in decreasing order of severity, as follows:

   FATAL | PANIC | ERROR | WARNING | INFO | DEBUG

The log messages are combined from all components and written into the standard error file (stderr). Logging can be controlled by the configuration of peers and modules, as well as in the code of the contract.

Configuration

The default configuration of peer logging is set to the level INFO, but this level can be controlled in the following ways:

  1. The following command returns the current logging level for a peer:
    peer logging getlogspec
    
  2. The following command sets the logging level, and the default...