README

Imagine you run a multi-head environment with TYPO3. Each application server is a "node".

As usual, there are caveats, and hurdles to work around with. Typically you have local cache files ("var/"), and (ideally) a FAL driver via a remote shared storage for "fileadmin". The database is on a cluster, and you run a Redis sentinel for shared caches.

But what about the other files that TYPO3 sometimes generates?

In an ideal world, TYPO3 would be handling most of the logic already, but due to some extensions or "compressed" files, some files get generated on e.g. "node 20" in typo3temp/ which aren't available on the other nodes.

In the past, we had NFS to work around this usually, but when NFS is not an option, we built a "workaround" extension for this, based on Frank De Jonge's Flysystem abstraction layer.

Every time a file in e.g. typo3temp gets accessed, and the file is not available on this node, the other nodes are checked via SFTP and if one node has the file, it is downloaded on the current nodes' typo3temp/ folder.

Currently, this extension is a "pull" solution - fetching the files if needed - but a deeper integration with the Local driver of the File Abstraction Layer should monitor this behavior as well in a separate step.

Installation

Set it up via composer: composer req b13/distributed-flysystem.

Configuration

Add a proper configuration for your SFTP connection to all your nodes in your LocalConfiguration for example:

$GLOBALS['TYPO3_CONF_VARS']['FILE']['flysystem'] = [
    'default' => [
        'rootPath' => '/path/from/sftp/ch-root/to/public/path/',
        'username' => 'b13',
        'password' => null,
        'port' => 2222,
        'privateKey' => Environment::getVarPath() . '/my-sftp_privkey',
        'passphrase' => 'take it or leave it',
        'timeout' => 10
    ],
    'nodes' => [
        'node01' => [
            'host' => '1.2.3.4'
            'alias' => 'primary'
        ],
        'node02' => [
            'host' => '1.2.3.5',
            'username' => 'b14',
        ],
    ],
];

Modify your .htaccess file on each node to activate the "pulling" mechanism:

# Rewrite non-existent fileadmin and typo3temp files to a custom eID script
RewriteCond %{REQUEST_URI} "^(/fileadmin|/typo3temp/assets/).*" [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule ^.*$ %{ENV:CWD}index.php?eID=flysystem [QSA,L]

Caveats

It is expected that the rootPath variable is set to the folder of the public directory of TYPO3's installation.

License

As TYPO3 Core, distributed flysystem is licensed under GPL2 or later. See the LICENSE file for more details.