# Deployer — Zero-Downtime PHP Deployment Tool

> Deployer is a deployment tool for PHP projects that provides zero-downtime atomic deployments with built-in recipes for Laravel, Symfony, and other popular frameworks.

## Install

Save in your project root:

# Deployer — Zero-Downtime PHP Deployment Tool

## Quick Use
```bash
composer require deployer/deployer --dev
vendor/bin/dep init
vendor/bin/dep deploy production
```

## Introduction
Deployer automates PHP application deployments over SSH with atomic symlink releases. It eliminates downtime by preparing new releases in a separate directory and switching a symlink only after all tasks succeed.

## What Deployer Does
- Executes zero-downtime deployments via atomic symlink switching
- Provides built-in recipes for Laravel, Symfony, WordPress, and more
- Manages multiple servers and deployment stages
- Supports parallel deployment to multiple hosts simultaneously
- Rolls back to previous releases on failure automatically

## Architecture Overview
Deployer connects to remote servers via SSH (using phpseclib or native SSH). Each deployment creates a new release directory, runs build tasks (composer install, asset compilation), and atomically switches the `current` symlink. A configurable number of past releases are kept for rollback. Recipes are PHP files defining tasks, and custom tasks can hook into any stage of the pipeline.

## Self-Hosting & Configuration
- Install globally with `composer global require deployer/deployer` or per-project
- Initialize config with `dep init` which generates `deploy.php`
- Define hosts with SSH credentials or agent forwarding
- Set shared files and directories that persist across releases
- Configure the number of releases to keep with `set('keep_releases', 5)`

## Key Features
- Atomic deployments with instant symlink switching
- Built-in recipes for 20+ PHP frameworks and CMSes
- Parallel execution across multiple servers
- Automatic rollback on task failure
- Provisioning support for setting up fresh servers

## Comparison with Similar Tools
- **Capistrano** — Ruby-based deployer; Deployer offers the same model in PHP
- **Envoyer** — Laravel-hosted deployment SaaS; Deployer is open source and self-managed
- **Kamal** — Docker-based deployment; Deployer works with traditional PHP hosting without containers
- **Ansible** — general infrastructure automation; Deployer is specialized for PHP deployment workflows
- **GitHub Actions** — CI/CD platform; Deployer handles the deployment stage specifically with rollback support

## FAQ
**Q: Does Deployer require root access on the server?**
A: No. It works with a regular SSH user that has write access to the deployment directory.

**Q: Can Deployer run database migrations during deployment?**
A: Yes. You can add migration commands as tasks in the deployment recipe.

**Q: How does rollback work?**
A: Deployer keeps previous releases on disk and switches the `current` symlink back to the last working release with `dep rollback`.

**Q: Does Deployer support Docker-based deployments?**
A: Deployer is designed for traditional server deployments but can run Docker commands as custom tasks.

## Sources
- https://github.com/deployphp/deployer
- https://deployer.org/docs

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Source: https://tokrepo.com/en/workflows/asset-f44a6cc3
Author: AI Open Source