An immutable deployment promotes a prebuilt image through environments rather than installing dependencies or editing PHP code on the live server.
What It Does
Composer dependencies are resolved at build time from the lock file. Build once and record the resulting image identity.
Requirements and Compatibility
Use a supported PHP runtime and install any third-party tool or extension explicitly shown in the examples. Commands should be run from the project root unless stated otherwise.
Syntax, Inputs and Results
The examples separate configuration, the smallest working operation and a realistic follow-up task. Adapt file paths and dependency versions to your own project.
Example 1: Basic Use
Composer dependencies are resolved at build time from the lock file.
FROM php:8.4-cli
WORKDIR /app
COPY --from=composer:2 /usr/bin/composer /usr/local/bin/composer
COPY composer.json composer.lock ./
RUN composer install --no-dev --prefer-dist --no-interaction --no-scripts
COPY src/ ./src/
CMD ["php", "src/worker.php"]Example 2: Another Case
Build once and record the resulting image identity.
docker build -t local/php-worker:1.0 .
docker image inspect local/php-worker:1.0 --format '{{.Id}}'Practical Example
Use a read-only filesystem and provide secrets at runtime rather than during build.
docker run --rm --read-only --tmpfs /tmp --env-file .env local/php-worker:1.0For production, apply the compatibility and edge-case limits described below.
Important Behavior and Edge Cases
Pin runtime dependencies, avoid baking credentials into the image, and deploy using a digest or versioned release artifact.
Comparison with Related Functions and Tools
| Subject | Key difference |
|---|---|
| GD vs Imagick | GD is a lightweight pixel API; Imagick depends on ImageMagick and supports other transformations and formats. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Trusting upload MIME declarations alone | Decode the file with an approved decoder and cap bytes and pixel dimensions. |
| Skipping the prerequisite of this specific workflow | Install or configure the named tool and confirm the example can actually run. |
| Ignoring edge conditions | Pin runtime dependencies, avoid baking credentials into the image, and deploy using a digest or versioned release artifact. |
Key Takeaways
- An immutable deployment promotes a prebuilt image through environments rather than installing dependencies or editing PHP code on the live server.
- Pin runtime dependencies, avoid baking credentials into the image, and deploy using a digest or versioned release artifact.
- Keep application configuration, source code and validation tests under version control.
Use these examples as a starting point, then validate the result with the actual PHP build, dependencies and inputs used by your application.