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PHP with Docker

PHP course · Expert · Lesson 43/54

Learn to set up a PHP development environment with a Dockerfile and docker-compose.

Dockerfile and php:8.3-fpm

A Dockerfile is the recipe for a Docker image: which base, which files, which command to run. Each line starts with a directive.

For PHP the official php:8.3-fpm base image is common; PHP-FPM runs out of the box. FROM picks the base, COPY copies source files in, EXPOSE 9000 declares the FastCGI port.

To generate a Dockerfile from PHP code you can write the text to disk with file_put_contents.

COPY, EXPOSE and CMD

The COPY directive copies source files into a directory inside the image. COPY . /var/www/html moves your current folder into /var/www/html in the image.

EXPOSE 9000 declares that the image listens on port 9000; this is the default FastCGI port for PHP-FPM and is reachable from outside.

In a multi-step Dockerfile each line carries one directive; blank lines and lines starting with # count as comments. CMD tells which command runs when the image starts.

Exercise Generate and write a Dockerfile

Build a Dockerfile text with PHP: lines FROM php:8.3-fpm, COPY . /var/www/html, EXPOSE 9000 and CMD ["php-fpm"]. Write it to a file named Dockerfile via file_put_contents and echo the text.

Show example solution 
Build $dockerfile with single-quoted parts joined by "\n". Then call file_put_contents("Dockerfile", $dockerfile); and echo $dockerfile;.
Example solution:
<?php
// Generate Dockerfile content
$dockerfile = 'FROM php:8.3-fpm' . "\n" .
    'COPY . /var/www/html' . "\n" .
    'EXPOSE 9000' . "\n" .
    'CMD ["php-fpm"]' . "\n";
file_put_contents("Dockerfile", $dockerfile);
echo $dockerfile;

Test yourself

  1. Which Dockerfile directive picks the base image?

    • RUN
    • FROM
    • CMD
    • EXPOSE
    Show answer

    FROM — Correct. The FROM directive sets the base image; it goes first.

  2. Complete the FROM line

    <?php
$df = ["line" => "____ php:8.3-fpm\n"];
print_r($df);
    Show answer 
    <?php
$df = ["line" => "FROM php:8.3-fpm\n"];
print_r($df);

  3. Match the Dockerfile directives

    FROM
    Picks the base image
    COPY
    Copies source files
    EXPOSE
    Declares a port
    CMD
    Start command

All lessons in Expert

1 Generators

  1. The yield keyword
  2. The Generator class
  3. Memory efficiency
  4. Infinite generators
  5. Delegation with yield from
  6. Pipeline with generators
  7. Summary - Generators

2 Closures and callbacks

  1. The Closure class
  2. Capturing variables with use
  3. Arrow functions (fn)
  4. The callable type
  5. Higher-order functions
  6. Closure binding (bindTo)
  7. Summary - Closures and callbacks

3 Reflection

  1. What is reflection?
  2. ReflectionClass
  3. ReflectionMethod
  4. ReflectionProperty
  5. Reading annotations
  6. Dynamic method invocation
  7. Summary - Reflection

4 Performance

  1. OPcache configuration
  2. Profiling tools
  3. Memory management
  4. Benchmarking
  5. The N+1 query problem
  6. Lazy loading
  7. Summary - Performance

5 Advanced security

  1. password_needs_rehash()
  2. Rate limiting
  3. Security headers (CSP, HSTS)
  4. Session fixation prevention
  5. Input sanitization
  6. Secure file upload
  7. Summary - Advanced security

6 Modern PHP

  1. readonly property
  2. Enums
  3. The match expression
  4. Named arguments
  5. Fibers
  6. First-class callable syntax
  7. Summary - Modern PHP

7 Deployment

  1. PHP with Docker
  2. PHP-FPM configuration
  3. Nginx configuration
  4. CI/CD basics
  5. Environment management
  6. Zero-downtime deployment
  7. Summary - Deployment

8 Expert final

  1. Challenge - Generators and closures
  2. Challenge - Reflection app
  3. Challenge - Performance optimization
  4. Challenge - Secure architecture
  5. Challenge - Full PHP app