Heroku Cloud Application Development
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This book is intended for those who want to learn Heroku the right way. Perhaps you are new to Heroku or are someone who has heard about Heroku but have not built anything significant with it. You should have knowledge or familiarity with cloud computing and basic knowledge of database and network deployment.
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Heroku Cloud Application Development - Anubhav Hanjura
Table of Contents
Heroku Cloud Application Development
Credits
About the Author
About the Reviewers
www.PacktPub.com
Support files, eBooks, discount offers and more
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
Errata
Piracy
Questions
1. Hello Heroku
What is cloud computing?
Cloud service models
What is cloud application development?
Key advantages of cloud application development
Introducing Heroku
Walking down the memory lane
An overview of Heroku's architecture
Process management
Logging
HTTP routing
Heroku interfaces
The Heroku feature set
Let's play Heroku
Getting ready for the ride – the prerequisites
Signing up
Installing the Heroku toolbelt
Logging in and generating a new SSH key
Test driving Heroku
Summary
2. Inside Heroku
The Heroku platform stack
The Celadon Cedar stack
Request routing in Heroku
The execution environment - dynos and the dyno manifold
Heroku's logging infrastructure – the Logplex system
The Heroku add-on architecture
Programmatically consuming Heroku services
The Heroku Platform API
Security
Schema
Data
Accessing the API
API clients
Calling the API
Response
Limits on API calls
The Heroku process architecture
Procfile
Declaring process types
The Procfile format
A sample Procfile
Adding Procfile to Heroku
Running applications locally
Setting local environment variables
Process formation
Process scaling
Stopping a process type
Checking on your processes
Process logs
Running a one-off process
Running anything
Summary
3. Building Heroku Applications
Heroku's guiding influence – the Twelve-Factor App methodology
A codebase is always versioned and it can have multiple deploys
Declare and isolate dependencies explicitly (always)
Configuration should be stored in the environment
Backend services should be treated as attached (loosely-coupled) resources
Strict separation of the build, release, and run stages of an app
An app in execution is a process or many processes
Services should be exported through port binding
An app should scale out through its process model
Faster startup and graceful shutdown is the way to app agility and scalability
Development and production (and everything in between) should be as similar as possible
The app should just log the event not manage it
App's administrative or management task should be run as a one-off process
Creating a Heroku application
Configuring your Heroku application
The Heroku application configuration API
Examples of using application configuration
The persistence of configuration variables
Accessing configuration variables at runtime
Limits on configuration data
Using the Heroku config plugin
Introducing buildpacks
Using a custom buildpack
Specifying a custom buildpack at the app creation stage
Third-party buildpacks
The buildpack API
Components of a buildpack API
The bin/detect script
The bin/compile script
The bin/release script
Writing a buildpack
The slug compiler
Optimizing the slug
Size limits
Summary
4. Deploying Heroku Applications
Deployment on Heroku
Getting a Heroku account
Installing the toolbelt client kit
Logging into the Heroku account
Setting up SSH
Writing your application
Pushing your application to Heroku
The Git vocabulary
Getting started with Git
Tracking a new project
Using an existing Git project
The life cycle of an artifact in Git
Tracking files in a Git project
When you don't need Git to track your files
The git diff command – knowing what changed
Committing your changes
Deleting a file
Moving a file
Viewing commit history
Undoing a change
You can use some Git help
The local repository
Remote repositories
Creating a Heroku remote
Renaming an application
Sending code to Heroku
Optimizing slug size
Cloning existing Heroku applications
Forking an application
Side effects of forking an application
Transferring Apps
Optimizing deployments
The choice of a region
Tracking application changes
Setting up Deploy Hooks
Basecamp
Campfire
HTTP
IRC
Release management
Checking installed releases
Verifying the new release
Rolling back the release
Summary
5. Running Heroku Applications
The Heroku app lifecycle
The Heroku CLI
How to get the Heroku client tool
Verifying the tool
How to get the latest Heroku client tool
Where is the Heroku client stored?
What if my client installation is corrupted or not working?
The Heroku CLI commands
Heroku CLI commands by function
Extending the Heroku CLI
The Heroku CLI and add-ons
A note on Heroku CLI and security
Running your cloud apps locally
Using Foreman to check Procfiles
Using Foreman to run apps directly
Running one-off commands
Foreman command-line options
The Apps page
The Resources tab
Managing resources
The Activity tab
The Access tab
The Settings tab
The Run Production Check tab
Heroku support
Summary
6. Putting It All Together
Heroku's support for Java
General support for Java
Database support for Java apps
Environment configuration
Integrating Eclipse with Heroku
Prerequisites
Configuring Heroku in Eclipse
Installing the Eclipse plugin for Heroku
Setting up Heroku for development
Setting up SSH support
Creating a new Heroku Java app in Eclipse
Using an existing Heroku application
Pushing code to Heroku
Pushing code to the Git repository
Managing Heroku apps in Eclipse
Viewing your Heroku application
Getting to the application's details
Reviewing the application's details
Going deeper into the application information
Adding collaborators to the application
Changing the environment variables
Heroku's process management in Eclipse
Scaling your app dynos
Restarting your web app
Summary
7. Heroku Best Practices
The One Cloud development platform
Introducing the Cloud 9 IDE
The C9 user interface
The C9 project view
Setting up preferences in the C9 IDE environment
Deploying on Heroku
Performing Git operations using the C9 IDE
Heroku and the data store
Creating a Heroku Postgres database
Logging in to the database
Creating more databases – the fork
Synchronizing databases via database followers
Checking database logs
Performance and the Heroku Postgres database
Disaster recovery in Heroku PostgreSQL
Importing data into Postgres
Deleting a Heroku Postgres database
Accessing Heroku Postgres externally
Accessing the database credentials
Connecting from outside of Heroku
High availability Postgres
Choosing the right plan
When does Heroku Postgres failover?
Effect of the failover
Checking the availability status after failover
Configuring domains the right way
Overview of DNS
Working with DNS in Heroku
Configuring your domain
Domain addition rules
Adding a custom domain to Heroku
Configuring domain DNS
Checking DNS configuration
Removing Heroku custom subdomains
Other domain-related considerations
Optimizing applications
The 2X dyno effect
When do I need the 2X dynos?
Checking whether you need 2X dynos
What if I use 2X dynos?
Now some examples...
Notes on 2X dynos
Managing your app dynos
Using the Heroku scheduler
Using NewRelic to keep the dyno alive
Summary
8. Heroku Security
Overview
Communication between the developer's machine and the Heroku platform
General concepts of security
Security of developer communication with Heroku
A look inside the SSH protocol
Client authentication
App security and the Heroku dashboard
Your Heroku account and the dashboard
Security of applications and data resident on Heroku and third-party servers
Heroku security practices
Source code security
Build and deploy security
Application security
Data security
Configuration and metadata
Infrastructure security
Security in add-ons
Securing the logging infrastructure
Network security
Security standards and compliance
Securing web requests
Piggyback SSL
SSL for a custom domain
Application security tools
wwwhisper
A sample wwwhisper app
Getting wwwhisper
Removing wwwhisper
Enabling wwwhisper in your application
For other Rack-based applications
Post wwwhisper enablement
Local setup for wwwhisper
Using wwwhisper locally
Disabling wwwhisper in a local environment
Tinfoil website security scanner
Upgrading the add-on
The TINFOILSECURITY_SCAN_SCHEDULE configuration parameter
The Tinfoil security scanner dashboard
The scanning process
Summary
9. Troubleshooting Heroku Applications
The need for troubleshooting
Your window to the running app – the logs
A little more about Logplex – Heroku's logging system
Sources and drains
The message limit
Retrieving Heroku logs
Getting last 'n' log messages
Getting live log messages
Setting up logging levels
Dissecting the Heroku log message
Log message types
Log filters
Examples of log filtering
Getting more from logging – other logging tools
Techniques for troubleshooting your app
Troubleshooting application downtime
Debugging HTTP requests and APIs
Validating your process formation
Checking your database
When everything else fails
Production check
A recommended Heroku configuration
The stack
The process formation
Database service
Domain and security considerations
Proactive health monitoring
Maintenance windows
Checking the maintenance status
Enabling the maintenance mode
Disabling the maintenance mode
The maintenance window – behind the scenes
Customizing site content
Customizing error pages
Testing custom maintenance and error pages
When requests time out
Error classification in Heroku
Summary
10. Advanced Heroku Usage
Experimenting with Heroku Labs
Using Heroku Labs features
Seamless deployment using pipelines
Enabling the pipelines feature
Performance monitoring
Switching on monitoring
Log snapshot
Watching your app closely using the Request ID
Supporting the Request ID
Introducing Websockets
Websocket versus HTTP
Websocket is not HTTP
Websocket use cases
Typical apps using Websockets
Supporting Websockets in your app
Establishing a Websocket connection
Disadvantages of using Websockets
Heroku and Websockets
Switching on Websocket support
Turning Websockets off
The Websockets example
The server code
The client code
Your first Heroku Platform API call
Before we get started
Supported API methods
Sample uses of the platform API
Creating an application
Create an application API response
Retrieving application information
Modifying application information
Deleting an application
Interpreting an API response
Error operations
Error format
An example error response
Warnings
Sharing your app on Heroku
Prerequisites for collaboration
Adding app collaborators to the Heroku dashboard
Deleting a collaborator
Adding collaborators via the Heroku CLI
Listing collaborators
Removing a collaborator
Collaborator actions
Working on the app
Viewing the app
Summary
Index
Heroku Cloud Application Development
Heroku Cloud Application Development
Copyright © 2014 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 authors, 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 2014
Production Reference: 1170414
Published by Packt Publishing Ltd.
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ISBN 978-1-78355-097-5
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Cover Image by Sagar Shiriskar (<[email protected]>)
Credits
Author
Anubhav Hanjura
Reviewers
Andy Dirnberger
Aki Iskandar
Ritesh Kumar
Andrea Mostosi
Ariejan de Vroom
Acquisition Editors
Kartikey Pandey
Gregory Wild
Content Development Editor
Azharuddin Sheikh
Technical Editors
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Neha Mankare
Shiny Poojary
Copy Editors
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Gladson Monteiro
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Shambhavi Pai
Alfida Paiva
Adithi Shetty
Laxmi Subramanian
Project Coordinator
Shiksha Chaturvedi
Proofreaders
Simran Bhogal
Maria Gould
Ameesha Green
Paul Hindle
Indexers
Hemangini Bari
Tejal Soni
Graphics
Ronak Dhruv
Disha Haria
Yuvraj Mannari
Abhinash Sahu
Production Coordinator
Arvindkumar Gupta
Cover Work
Arvindkumar Gupta
About the Author
Anubhav Hanjura is a cloud technology enthusiast and a software architect. He specializes in server-side development (C++, C, and Java) for distributed software platforms, and is an avid blog reader. When he is not designing software systems, you can find him collecting books, pondering over puzzles, or bookmarking general trivia. He is a passionate mentor, has authored several white papers, and has also served as a project guide for students on many occasions. He holds a Bachelor's degree in Computer Engineering from NIT, Surat.
I would like to thank my parents, Roshan and Usha, for constantly reminding me of the value of sharing. I would like to thank my teachers and friends for inspiring and believing in me. Last but not the least, I would like to thank my daughter, Edha and my wife, Sheetal for letting me steal their time to write this book.
About the Reviewers
Aki Iskandar is an entrepreneur and software architect. He owns and operates two small software companies—one is a consultancy, specializing in Ruby on Rails and native iOS development, and the other provides an online marketing platform for small companies. This online service has been completely built using Ruby on Rails, and is hosted on the Heroku infrastructure. Aki has launched other subscription-based online services, before the days of cloud computing, claiming that he was spending more time administering the servers (load balancing, databases, replication, web servers, e-mail servers, monitoring, file syncs, and so on) than writing code for the applications. Today, he recommends that his clients take the cloud computing route over self-hosting, with very few exceptions. His favorite cloud provider is Heroku.
Prior to starting his companies, he spent 14 years as a consultant. During that time, he was a consultant for various large companies, including Microsoft, Compuware, Progressive Insurance, Allstate Insurance, KeyBank, Ernst & Young, and Charles Schwab. In his last full-time position, which was almost three years ago, he served as an enterprise architect at PNC Bank (as a core member of PNC's Enterprise Architecture team, and he also co-chaired their Architecture Review Board). You can read Aki's blog and learn more about his companies on his personal website www.iskandar.us. He lives with his son, Justin, in the suburbs of Cleveland, Ohio.
Andrea Mostosi is a passionate software developer. In 2003, he started at high school with a single-node LAMP stack and he grew up by adding more languages, components, and nodes. He graduated from Milan and worked for several web-related projects. He is currently working with data, trying to discover information hidden behind huge datasets.
I would like to thank my girlfriend, Khadija, who lovingly supports me in everything I do. I would also like to thank the people I collaborated with, for fun or for work, for everything they taught me. Finally, I'd also like to thank Packt Publishing and its staff for this opportunity to contribute to this project.
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Preface
Cloud application development is the new black
. With the advent of server virtualization, hardware resources have become cheaper. You can buy hardware on demand and pay only for the time you use it. The next wave of virtualization is that of software virtualization, that is, having the ability to use available software on demand and build your own apps on top of it. Here too, you pay only for what you use and how long you use it. The Heroku Platform as a Service (PaaS) is a software platform that provides a combination of the underlying operation system resources, language runtime, and supporting software to help you build your own web apps on demand.
This book on Heroku cloud application development is intended to introduce you to the fundamentals of the Heroku Platform as a Service, and help you to understand the rich feature set of the Heroku platform that enables building powerful and scalable web apps. In addition, this book also showcases techniques to deploy and troubleshoot the web apps deployed on Heroku and helps you understand the nuances of the choices you have to make while building apps for the Heroku environment. And that isn't all. You will also be presented with the best practices of using Heroku for developing web apps as well as getting a feel for the advanced aspects of the platform. The book also educates the user on how to securely use the Heroku platform for developing production-ready and high-performance web apps.
In essence, Heroku cloud application development is all about rapid application development for the cloud, (re)using available software add-ons and underlying platform infrastructure to build, deploy, and manage really powerful and scalable web apps.
What this book covers
Chapter 1, Hello Heroku, introduces you to the world of Heroku. It also provides a historical background on how Heroku evolved to what it is today followed by a basic understanding of Heroku's architecture. Finally, it takes you on a test drive to get a firsthand experience with the Heroku cloud platform.
Chapter 2, Inside Heroku, covers the foundational aspects of the Heroku platform. It covers the details of various components of the Heroku architecture, including the Heroku platform stack, the request routing system, the Logplex logging framework, the add-ons, the dyno (process), and the platform API.
Chapter 3, Building Heroku Applications, covers the principles governing building web apps on the Heroku platform. It also illustrates the process of building and configuring web apps besides covering the steps involved in preparing a production-ready app from your code using language-specific buildpacks.
Chapter 4, Deploying Heroku Applications, describes the application deployment process on the Heroku platform. It covers the basics of the Git distributed version control system and illustrates the most common source management operations. It also covers the concept of forking and cloning apps besides ways to optimize your app deployment. It also showcases various aspects of Heroku app release management process through illustrative examples.
Chapter 5, Running Heroku Applications, illustrates the process of running a Heroku cloud app in detail. It covers the Heroku command-line interface (CLI) used to perform Heroku operations such as creating or updating apps. It also explains how to use the Foreman tool to troubleshoot the apps locally before deploying them to the Heroku cloud. Additionally, it describes the key features of the Heroku dashboard related to running Heroku apps.
Chapter 6, Putting It All Together, sums up the learning about the foundations of the Heroku platform and illustrates the whole process of building, deploying, and managing Heroku apps using Java on the Eclipse app development platform.
Chapter 7, Heroku Best Practices, covers the details of best practices that developers can use not only to deploy but also to write apps on the cloud using the Cloud 9 cloud-based integrated development environment. This chapter also provides detailed coverage of best practices such as setting up the Heroku PostgreSQL database, configuring DNS for your web app, and optimizing applications to use higher end services provided by the Heroku platform.
Chapter 8, Heroku Security, covers two parts of the Heroku security puzzle—the developer communication with the Heroku platform and securing the Heroku platform from malicious attacks from the external world.
Chapter 9, Troubleshooting Heroku Applications, describes the techniques developers can employ to fix problems encountered while developing apps for the Heroku platform. It covers how to troubleshoot application downtimes, isolates HTTP request issues, debugs database problems, and runs production checks to warn you about potential issues. It also shows how you can use the maintenance windows to gracefully handle app upgrades.
Chapter 10, Advanced Heroku Usage, introduces the advanced features of Heroku. It covers the Heroku Labs feature, including Websockets, illustrates the Heroku Platform API through practical examples, and shows how developers can do social coding using the collaborative features of the Heroku dashboard.
What you need for this book
The software needed for this book includes the Heroku toolbelt (client) (https://toolbelt.heroku.com), Eclipse IDE for EE, the Mozilla Firefox web browser, and the curl tool.
Who this book is for
This book is for application developers who are looking to learn cloud application development using the Heroku platform. Knowledge of Ruby and Java is desirable. Previous knowledge of the Ubuntu OS is helpful though not mandatory.
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: Use the ps:scale command to scale up the web processes.
A block of code is set as follows:
#!/bin/sh
cat << EOF
---
addons:
- heroku-postgresql:dev
default_process_types:
web: bin/node server.js
EOF
Any command-line input or output is written as follows:
$ heroku create myapp --buildpack https://github.com/heroku/heroku-buildpack-mylang
New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: You can also restart a web application using the Restart button on the Processes tab of your web app.
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
Reader feedback
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To send us general feedback, simply send an e-mail to <[email protected]>, and mention the book title via the subject of your message.
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Piracy
Piracy of copyright material on the Internet is an ongoing problem across all media. At Packt, we take the