Drush for Developers - Second Edition

Table of Contents

Drush for Developers Second Edition

Credits

About the Author

About the Reviewers

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Why subscribe?

Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Introduction, Installation, and Basic Usage

Installation requirements

Operating system

PHP

Installing Composer

Drush installation on Linux and OSX

Manual installation

The Drush command structure

Executing a command

Providing arguments to a command

Altering a command's behavior through options

Structuring command invocations

Command aliases

Understanding Drush's context system

Setting the context manually

Summary

2. Keeping Database Configuration and Code Together

Meeting the update path

Rebuilding the registry

Preparing the trap

Breaking the registry

Rebuilding Drupal's registry

Running database updates

Managing features

Exporting configuration into code

Running the update path on a different environment

Analyzing results

Reverting the feature components programmatically

Summary

3. Running and Monitoring Tasks in Drupal Projects

Running periodic tasks with cron

Disabling Drupal's cron

Verifying the current cron frequency

Overriding cron frequency and exporting it to code

Running cron with Drush

Scheduling cron runs with Jenkins

Installing Jenkins

Creating a job through the web interface

Monitoring cron runs

Running a task outside cron

Example – moving a Feeds importer from Drupal's cron to Drush

Exporting the Feeds importer into code

Writing a Drush command to trigger the Feeds importer

Running long tasks in batches

A sample Drush command using the Batch API

Batch API operations

Running the command and verifying the output

Evaluating code on the fly and running scripts

The php-eval command

The php-script command

A script to create nodes and revisions

Logging messages in Drush

The verbose and quiet modes

Redirecting Drush output into a file

Implementing your own logging mechanism

Running a command in the background

Summary

4. Error Handling and Debugging

Validating input

Validating an argument

Validating options

Ignoring options after the command name

Allowing additional options

Adding custom validation to a command

Rolling back when an error happens

Turning the update path into a single command

Browsing hook implementations

Inspecting the bootstrapping process

Inspecting hook and function implementations

Browsing and navigating hook implementations

Viewing source code of a function or method

Summary

5. Managing Local and Remote Environments

Managing local environments

Managing remote environments

Verifying requirements

Accessing a remote server through a public key

Defining a group of remote site aliases for our project

Using site aliases in commands

Special site aliases

Running a command on all site aliases of a group

Avoiding a Drupal bootstrap with @none

Referencing the current project with @self

Adding site alias support to the update path

Inspecting the command implementation and hooks

Running the update path with a site alias

Copying database and files between environments

Defining Drush shell aliases for a team

Blocking the execution of certain commands

Ignoring tables on sql-sync

Summary

6. Setting Up a Development Workflow

Moving configuration, commands, and site aliases out of Drupal

Installing Drupal Boilerplate

Relocating Drush files

Testing the new setup

Configuring the development database for the team

Configuring Jenkins to sync production to development

Fine-tuning the development database

Recreating the database on sql-sync

Excluding table data from production

Ignoring tables from production

Sanitizing data

Preventing e-mails from being sent

Running post sql-sync tasks in local environments

Summary

Index

Drush for Developers Second Edition

Drush for Developers Second Edition

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: April 2012

Second edition: January 2015

Production reference: 1240115

Published by Packt Publishing Ltd.

Livery Place

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Birmingham B3 2PB, UK.

ISBN 978-1-78439-378-6

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Credits

Author

Juampy Novillo Requena

Reviewers

Greg Anderson

Chris Burgess

Jonathan Araña Cruz

Jeremy French

Todd Zebert

Commissioning Editor

Dipika Gaonkar

Acquisition Editor

Meeta Rajani

Content Development Editor

Anila Vincent

Technical Editor

Arvind Koul

Copy Editor

Relin Hedly

Project Coordinator

Neha Bhatnagar

Proofreaders

Bridget Braund

Ameesha Green

Indexer

Tejal Soni

Production Coordinator

Alwin Roy

Cover Work

Alwin Roy

About the Author

Juampy Novillo Requena started working as a web developer in London. After spending a few years developing with plain PHP, Symfony, and Ruby on Rails, he discovered Drupal. Drawn by the Drupal community and the mind-blowing effect of getting a project done 10 times faster than before, Juampy has never looked back.

Since then, he's become more and more involved in the issue queues, which in turn led him to become a maintainer of core and contributed modules. He organizes events, gives sessions at national and international conferences, and has written the book Drush User's Guide, Packt Publishing. He feels privileged to experiment, have fun, and be challenged every day. He is known as juampy on Drupal.org and IRC. His Twitter account is @juampy72.

This book is the result of my two years working at Lullabot. Most of the contents explained here were originated by discussions or contributions within the team. I am very thankful to the team who worked on the MSNBC project, where we collaboratively developed and implemented best practices that are represented in this book.

I also want to thank the technical reviewers; their suggestions and corrections leveraged this book to a higher level.

Finally, a personal acknowledgement to the city of Niamey, Niger, where I did most of the writing.

About the Reviewers

Greg Anderson is an open source contributions engineer working on Drupal and WordPress at Pantheon in San Francisco. He has been contributing to Drush since just before the release of version 2, and remains an active co-maintainer to this day.

Chris Burgess is currently making the world better by building open source tools for activist and nonprofit organizations to campaign and communicate. He has been developing with Drupal since 2006, and he is immensely grateful to the Drupal and wider open source communities for the learning and sharing environment that they foster. Chris is based in Dunedin, New Zealand, with his two sons, Hunter and Rowan, and partner, Saira. He works for Fuzion Aotearoa, and you can reach him at @xurizaemon on Twitter, xur1z on IRC, or his Drupal.org profile at https://www.drupal.org/u/xurizaemon.

Jonathan Araña Cruz is a co-maintainer of Drush. He combines both sysadmin and Drupal development work. Jonathan has contributed several modules to Drupal, and as a sysadmin, he manages Infrastructure as Code with Puppet.

Jonathan's Drupal profile can be found at https://www.drupal.org/u/jonhattan.

Jeremy French has worked in web development for over a decade, floating through a wasteland of bespoke Content Management Systems, before finding Drupal. He has developed sites for a number of household names and blue chips, as well as a few interesting start-ups. Currently, he is working for a small agency, living the dream of distributed working.

Todd Zebert has been involved with Drupal since early version 6. He creates websites and web apps with a variety of technologies. Currently, Todd works as a lead web developer for Miles.

Todd has a diverse background in technology, including infrastructure, network engineering, project management, and IT leadership. His experience with web development started with the original Mosaic graphical web browser, SHTML/CGI, and Perl. His fondness for Drupal and his interest in workflow, efficiency, repeatable best practices, and DevOps drives his interest in Drush.

Todd is an entrepreneur involved with the start-up community. He's a believer in volunteering, open source, and contributing back. He's an advocate for Science, Technology, Engineering, Art, and Math (STEAM) education.

I'd like to thank the Drupal community, which is like no other.

Finally, I'd like to thank my pre-teen son with whom I get to share my interest in technology and program video games together.

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Preface

In this book, I share with you how I use Drush in my day-to-day work. When working on Drupal projects, Drush is omnipresent. It is a key tool to debug code, run small scripts, and discover APIs. However, this is just the beginning; Drush's real potential comes when teams use it to define a development workflow.

What this book covers

Chapter 1, Introduction, Installation, and Basic Usage, begins with Drush's requirements and installation and then shows its basic usage through examples.

Chapter 2, Keeping Database Configuration and Code Together, explains how to export configuration from the database into code in order to share it with the rest of the team and other environments.

Chapter 3, Running and Monitoring Tasks in Drupal Projects, gives different options to run tasks in Drupal projects such as cron, Batch API, and custom scripts.

Chapter 4, Error Handling and Debugging, explores tools that help us catch and process errors, so as to navigate through the available hooks and functions in our project.

Chapter 5, Managing Local and Remote Environments, unveils all the magic behind site aliases using a typical Drupal project that involves production and development environments.

Chapter 6, Setting Up a Development Workflow, leverages all the concepts covered in the book by defining a development workflow for a team.

What you need for this book

Here are the system requirements to run the examples in the book:

Operating system: Any Unix-based system such as:

Ubuntu (any version), available at http://www.ubuntu.com

MAC OS X (any version)

Software:

PHP 5.2 or higher, available at http://www.php.net

MySQL 5.0 or higher, available at http://www.mysql.com

Apache 2.0 or higher, available at http://www.apache.org

Drupal 7, available at http://drupal.org

Git, available at http://git-scm.com

Jenkins, available at https://wiki.jenkins-ci.org

Who this book is for

This book will fit best to backend developers with a basic knowledge of Drupal's APIs and some experience using the command line. Perhaps, you already worked on one or two Drupal projects, but have never dived deep into Drush's toolset. In any case, this book will give you a lot of advice by covering real-world challenges in Drupal projects that can be solved using Drush.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: Drush runs using a different PHP.ini configuration than the web server that does not have a request timeout.

A block of code is set as follows:

/**

* Callback to delete revisions using Batch API.

*/

function node_revision_delete_batch_process($content_type, $max_revisions, &$context) {

  if (!isset($context['sandbox']['nids'])) {

    // Set initial values.

    $context['sandbox']['nids'] = node_revision_delete_candidates($content_type, $max_revisions);

    $context['sandbox']['current'] = 0;

    $context['sandbox']['total'] = count($context['sandbox']['nids']);

  }

}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

/**

* Callback to delete revisions using Batch API.

*/

function node_revision_delete_batch_process($content_type, $max_revisions, &$context) {

  if (!isset($context['sandbox']['nids'])) {

    // Set initial values.     $context['sandbox']['nids'] = node_revision_delete_candidates($content_type, $max_revisions);     $context['sandbox']['current'] = 0;     $context['sandbox']['total'] = count($context['sandbox']['nids']);

  }

}

Any command-line input or output is written as follows:

$ drush php-script logging.php

success: marks a successful message.          [success]

error: reports an error message.              [error]

warning: is used to alert about something.    [warning]

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes for example, appear in the text like this: "You can test it by