Book Image

Blockchain Development with Hyperledger

By : Salman A. Baset, Luc Desrosiers, Nitin Gaur, Petr Novotny, Anthony O'Dowd, Venkatraman Ramakrishna, Weimin Sun, Xun (Brian) Wu
Book Image

Blockchain Development with Hyperledger

By: Salman A. Baset, Luc Desrosiers, Nitin Gaur, Petr Novotny, Anthony O'Dowd, Venkatraman Ramakrishna, Weimin Sun, Xun (Brian) Wu

Overview of this book

Blockchain and Hyperledger are open source technologies that power the development of decentralized applications. This Learning Path is your helpful reference for exploring and building blockchain networks using Ethereum, Hyperledger Fabric, and Hyperledger Composer. Blockchain Development with Hyperledger will start off by giving you an overview of blockchain and demonstrating how you can set up an Ethereum development environment for developing, packaging, building, and testing campaign-decentralized applications. You'll then explore the de facto language Solidity, which you can use to develop decentralized applications in Ethereum. Following this, you'll be able to configure Hyperledger Fabric and use it to build private blockchain networks and applications that connect to them. Toward the later chapters, you'll learn how to design and launch a network, and even implement smart contracts in chain code. By the end of this Learning Path, you'll be able to build and deploy your own decentralized applications by addressing the key pain points encountered in the blockchain life cycle. This Learning Path includes content from the following Packt products: • Blockchain Quick Start Guide by Xun (Brian) Wu and Weimin Sun • Hands-On Blockchain with Hyperledger by Nitin Gaur et al.
Table of Contents (25 chapters)
Title Page
Copyright
About Packt
Contributors
Preface
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, github.com/op/go-logging. 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:

CRITICAL | ERROR | WARNING | NOTICE | 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 chaincode.

Configuration

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

  1. A command line option logging level. This option overrides default configurations, shown as follows:
peer node start --logging-level=error  

Note that any module or chaincode can be configured through the command line option,...