Twelve Factor AppTomasz Skręt

I. Codebase

• One repository - GIT :)• One application per

repository• Extract shared code into

libraries• Running instance - deploy

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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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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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IV. Backing Services

Attached resources

• Databases• File storage• Cache• Queue• APIs

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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:

VI. Processes

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stateless

share nothing

use backing services

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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VIII. Concurrency

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scale by creating new processes

don’t write PID files - use ex. upstart, systemd, foreman

IX. Disposability

• applications are disposable - easy to scale, change configuration, deploy new version• fast start• gracefully shutdown

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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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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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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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Thank you for watching!

Questions?