Twelve simple rules, leads us to how to create modern, easy to develop, maintain and deploy application.

1. Twelve Factor App
Tomasz Skręt

2. I. Codebase
• One repository - GIT :)
• One application per repository
• Extract shared code into
libraries
• Running instance - deploy
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3. II. Dependencies
● Use packaging system
● Isolate dependencies
● Do not rely on system tools
● Installing dependencies
should be simple, one
command process
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4. III. Config
• Store config in environment
• Each deploy has own config
• Do not checkout into repository
• Do not group config values as a
environments
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5. IV. Backing Services
Attached resources
• Databases
• File storage
• Cache
• Queue
• APIs
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6. V. Build, release, run
• build - checkout codebase,
install dependencies, run tests,
produce artifact
• release - combine build artifact
with environment config
• run - run application processes
Every release have version
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3 stages:

7. VI. Processes
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stateless
share nothing
use backing services

8. VII. Port binding
• expose application by binding to port
• one twelve factor app can become
backing service for another
• in PHP to expose HTTP service, we
can use nginx or haproxy
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9. VIII. Concurrency
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scale by creating new processes
don’t write PID files - use ex. upstart, systemd, foreman

10. IX. Disposability
• applications are disposable - easy to scale, change configuration, deploy
new version
• fast start
• gracefully shutdown
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11. X. Dev/prod parity
• environments should be similar
to production as much as
possible
• keep time gap small
• environment should be setup
fast and easy
• backing services can be
changed to another, ex. to
simplify development process
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12. XI. Logs
• Treat logs as event streams
• twelve-factor app never
concerns itself with routing or
storage of its output stream
• logs are collected from
application and all backing
services
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13. XII. Admin processes
• one-off process
• should run in identical environment - run the same codebase and
config as application - use release
• can be script, committed to repo
• REPL console
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14. Thank you for watching!
Questions?