Composer Preload

Preload your sweet sweet code to opcache with a composer command, making your code run faster.

Composer Preload is a composer plugin aiming to provide and complement PHP opcache warming. This plugin introduces a new composer preload command that can generate a vendor/preload.php file (following vendor/autoload.php pattern) that contains calls to warm up the opcache cache.

Please note that this plugin is currently in a very rudimentary state, and it is highly recommend to not use this in any production system. Any contributions are warmly welcome!

How it works

At the moment, this plugin scans for .php files in the given paths recursively, and create a file that calls opcache_compile_file function.

When you want to warm up the cache, you can either call php vendor/preload.php in command line, or when PHP 7.4 hits the shelves, configure PHP to automatically load this file.

Installation

Just the way you'd install a normal composer package, you can install this plugin aswell:

composer require ayesh/composer-preload

If you would rather install this globally:

composer g require ayesh/composer-preload

Configuration

1: Modify your composer.json file, and create a section called extra if it's not there already. Following is an example:

{
    "extra": {
        "preload": {
            "paths": [
                "web"
            ],
            "exclude": [
                "web/core/tests",
                "web/core/lib/Drupal/Component/Assertion",
                "web/core/modules/simpletest",
                "web/core/modules/editor/src/Tests"
            ],
            "extensions": ["php", "module", "inc", "install"],
            "exclude-regex": "/[A-Za-z0-9_]test\\.php$/i",
            "no-status-check": false,
            "files": [
                "somefile.php"
            ]
        }
    }
}

The extra.preload directive contains all the configuration options for this plugin. The paths directive must be an array of directories relative to the composer.json file. These directories will be scanned recursively for .php files, converted to absolute paths, and appended to the vendor/preload.php file.

2: Run the composer preload command.

3: Execute the generated vendor/preload.php file. You can either run php vendor/preload.php or use your web server to execute it. See the Preloading section below for more information.

Configuration options

• extra.preload.paths : Required

An array of directory paths to look for .php files in. This setting is required as of now. The directories must exist at the time composer preload command is run.

• extra.preload.exclude : Optional

An array of directory paths to exclude from the preload.php. This list must be relative to the composer.json file, similar to the paths directive. The ideal use case limiting the scope of the paths directive.

• extra.preload.extensions : Optional, Default: ["php"]

An array of file extensions to search for. If not entered, it will search for all .php files. Do not enter the proceeding period (.) character. The example above is suitable for Drupal. For Symfony/Laravel projects, you can leave the default option ["php"] or just not use this option so it defaults to just .php.

• extra.preload.exclude-regex : Optional

Set a PCRE compatible full regular expression (with delimiters and modifiers included) that will be matched against the full path, and if matched, will be excluded from the preload list. This can help you exclude tests from the preload list.

For example, to exclude all PHPUnit-akin tests, you can use the regular expression /[A-Za-z0-9_]test\\.php$/i. This will make sure the file name ends with "test.php", but also has an alphanumeric or underscore prefix. This is a common pattern of PHPUnit tests. The /i modifier makes the match case insensitive.

For directory separators, always use Unix-style forward slashes (/) even if you are on a Windows system that uses backwards slashes (\). Don't forget to properly escape the regex pattern to work within JSON syntax; e.g escape slashes (\ and /) with a backwards slash (\ -> \\ and / -> \/). This will make the regular expression hard to read, but ¯\(ツ)/¯.

• extra.preload.no-status-check: Optional, Default: false

If this setting is set to true (you can also pass command line option --no-status-check), make the generated preload.php file not contain additional checks to make sure the opcache is enabled. This setting is disabled by default, and the generated preload.php file will contain a small snippet on the top that makes it quit if opcache is not enabled.

• extra.preload.files : Optional

An array of single files to be included. This setting is optional. The files must exist at the time composer preload command is run.

Preloading

To do the actual preloading, execute vendor/preload.php.

If you have enabled opcache for CLI applications, you can directly call php vendor/preload.php to execute the generated PHP file and warm up the cache right away.

Future versions of this plugin will have a feature to generate the file and immediately run it.

In a webserver context, or when you cannot run the PHP file with the CLI php binary. this probably means you'll want to link vendor/preload.php into your docroot somwhere and curl it. For example, ln -s vendor/preload.php path/to/docroot/preload.php and then curl localhost/preload.php on webserver startup.

FAQ

What does this plugin even do?

This plugin can create a new file at vendor/preload.php that follows the pattern of Composer's autoloader at vendor/autoload.php. This new preload.php file contains several function calls that compiles PHP files and cache them into PHP's opcache. PHP Opcache is a shared memory (with optional file storage option) feature in PHP that can hold compiled PHP files, so the same file doesn't need to be compiled again and again when its called. This is a persistent memory until PHP is restarted or the cache is eventually cleared.

Caching files in opcache has siginificant performance benefits for the cost of memory.

So all the files are loaded all the time?

All the files are loaded to the Opcache. This is not same as you include() or require() a class, which makes PHP actually execute the code. When you cache code to Opcache, those classes are not executed - just their compiled code is cached to the memory.

For example, if you declare a variable, this plugin's preload functionality will not make the variables available inside your PHP code. You still have to include the file to make them available.

I have the vendor/preload.php file. What now?

After generating the file, you might need to actaully run it effectively load the files to Opcache. Ideally, you should do this every time you restart your web server or PHP server, depending on how you serve PHP within your web server.

PHP 7.4 has a php.ini option opcache.preload that you can specify this generated file, or a separate file that calls all vendor/preload.php files you have across your server to actively warm up the cache.

I have multiple Composer projects running on same server.

You can generate the preload file for each project, and include all of them in a separate PHP file you create by yourself. Then, call all of the generated vendor/preload.php files.

By default, the preload file will contain a small snippet at the top that will quit the script immediately if Opcache is not available. If you plan to include this vendor/preload.php file from another script, you can use the special command line option composer preload --no-status-check that will make the vendor/preload.php file not contain these checks, so you can incude multiple vendor/preload.php files across all your projects without running the same snippet over and over. It is recommended that you make sure Opcache is enabled before doing so. Feel free to copypasta the snippet from one of your generated preload files.

Can I generate the preload file in one server and use it in another server?

Yes. Similar to the vendor/autoload.php file, vendor/preload.php file this plugin generates also uses relative paths. From version v0.1.0 and forward, you can generate the preload file at one server and reuse it in other servers (directory hierarchies).

You will still need to run the vendor/preload.php file in all servers that you want to preload opcache.

Roadmap

• ☐ Extend extras.preload section to configure the packages that should be preloaded instead of setting the individual paths.
• ✓ Feature to set an exclude pattern (v0.0.3)
• ☐ Progress bar to show the file generation progress
• ☐ Flag to generate the file and run it, so the cache is immediately warmed up.
• ☐ Fancier progress bar.
• ⭕ Full test coverage.
• ☐ Even more fancier progress bar with opcache memory usage display, etc.
• ⭕ Get many Github stars