runopencode/backup

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Simple web application backup library, fork of 'kbond/php-backup'.

1.0.4 2017-02-08 23:53 UTC

This package is auto-updated.

Last update: 2019-03-16 22:22:42 UTC


README

This library is depreciated, please use https://phpbu.de

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NOTE: This library is fork of 'kbond/php-backup' library with significant modifications which disables compatibility with its original.

Every process of backup can be broken down to several activities:

  • Prepare files to backup from various sources (filesystem, database...)
  • Process those files somehow (create zip archive, per example) and name it according to some convention
  • Determine if there is sufficient backup space on your backup storage system, and delete old backups if neccessary
  • Copy new backup to backup destination (usually into new folder named with current date and time)

Having in mind the process stated above, we can identify several major parts of backup system:

  • Source of files which needs to be backed up. Even database belongs to this category, since database backup is a file.
  • Backup is collection of Files retrieved from Sources.
  • Processor process Files within backup somehow (usually compress them into single archive, but it is not limited to mentioned).
  • Namer provides new name for Backup according to some desired rule (timestamping or similar).
  • Rotator checks previous backups within backup storage and removes old backups if some rotation constraint is violated (per example, max size of backup storage).
  • Destination is abstraction of backup storage where backups residue.
  • Workflow is abstraction of backup process which is executed trough sequence of backup activities. This library provides default workflow, which can be replaced with your own if default one does not suits your needs.
  • Profile is collection of all above stated, it defines what have to backed up, how backup has to be processed, what name to use, where to store new backups and how to rotate old backups.
  • Manager is collection of profiles, he provides profiles with Logger and EventDispatcher and executes them.

Note that author of this brilliant idea on how to brake down to fundamental backup system components is Kevin Bond.

See if this library is for you by evaluating simple example

Let's backup our website by creating simple application that will be executed by crontab. Let's say that our code is in some app.php file (Don't be scared with amount of code - each line is commented so you can understand the concept with ease).

<?php 
/**
 * file: app.php
 */

require_once('vendor/autoload.php'); // We are going to use composer for autoloading.

use Psr\Log\NullLogger;
use Symfony\Component\EventDispatcher\EventDispatcher;
use RunOpenCode\Backup\Source\MySqlDumpSource;
use RunOpenCode\Backup\Source\SourceCollection;
use RunOpenCode\Backup\Processor\ZipArchiveProcessor;
use RunOpenCode\Backup\Namer\Timestamp;
use RunOpenCode\Backup\Rotator\NullRotator;
use RunOpenCode\Backup\Rotator\MaxCountRotator;
use RunOpenCode\Backup\Destination\FlysystemDestination;
use RunOpenCode\Backup\Backup\Profile;
use RunOpenCode\Backup\Workflow\Workflow;
use RunOpenCode\Backup\Manager;

use League\Flysystem\Dropbox\DropboxAdapter;
use League\Flysystem\Filesystem;
use Dropbox\Client;

$logger = new NullLogger();                                 // Or you can use concrete logger if you like.
$eventDispatcher = new EventDispatcher();                   // We need event dispatcher as well.

// Let's define source of our website files, we will use glob source to fetch files
// Array keys are path to directories where files residue, while values are path prefixes which we would like to remove
// and work only with relative paths
$files = new GlobSource(array(
    '/path/to/directory/with/files' => 'path/to/directory',           
    '/other/path/to/directory/with/files' => 'other/path'            
));

// Let's backup database as well...
$settings = array(...);
$database = new MySqlDumpSource($settings['database'], $settings['username'], $settings['password'], $settings['host'], $settings['port']);

// Our files and databases are things that we are want to backup, so we have to use source collection...
$source = new SourceCollection(array(
    $files,
    $database
));

// We will zip our backup files in order to save storage space 
$processor = new ZipArchiveProcessor('archive.zip');
// Note that processor requires event dispatcher...
$processor->setEventDispatcher($eventDispatcher);

// Our backups will get name based on current timestamp
$namer = new Timestamp();

// We will not use pre-rotator...
$preRotator = new NullRotator();
// But we will use post-rotator... (see docs below for difference, this is just example) limiting number of backups to some number.
$postRotator = new MaxCountRotator(5);

// And let's define our backup storage, per example, Dropbox via Flysystem (which is optional).
// @see http://flysystem.thephpleague.com/adapter/dropbox/
$client = new Client($accessToken, $appSecret);
$adapter = new DropboxAdapter($client, [$prefix]);
$filesystem = new Filesystem($adapter);
$destination = new FlysystemDestination($filesystem);

// When we have components, lets define our profile:
$profile = new Profile('my-profile', $source, $processor, $namer, $preRotator, $destination, $postRotator);

// We need workflow for manager, so we will build it and provide it with logger and event dispatcher
$workflow = Workflow::build();
$workflow->setEventDispatcher($eventDispatcher);
$workflow->setLogger($logger);

// Finally, we will create manager, and feed him with profile.
$manager = new Manager($workflow, array($profile));

// And we can now execute backup process...
$manager->execute('my-profile');

This library provides you with very flexible way to define and execute your backups. However, library is intended to be used within frameworks where profile construction process ought to be simplified via various configurations possibilities of concrete framework.

Do read further more to find out how to use and extend library to your needs.

Source and File

Source is defined within RunOpenCode\Backup\Contract\SourceInterface and have only one method defined: fetch(). Expected result from Source implementation is collection of RunOpenCode\Backup\Contract\FileInterface. File interface is abstraction of file which is subject of backup process. Concrete implementation is provided within this library as RunOpenCode\Backup\Backup\File.

Backup library currently provides you with several SourceInterface implementations:

  • RunOpenCode\Backup\Source\NullSource which is empty implementation of above mentioned interface which is used for testing purposes, but it can be used as well in production environment in conjunction with events (which will be explained later on).
  • RunOpenCode\Backup\Source\GlobSource which fetches files to backup from local drive using glob expressions (see glob for more details.)
  • RunOpenCode\Backup\Source\MySqlDumpSource which fetches MySQL dump output in file and allows you to backup your MySQL database.
  • RunOpenCode\Backup\Source\SourceCollection which is collection of several SourceInterface implementations. It allows you to use several sources at once for your backup profile (per example, to backup both files and databases of your web application).

Backup

Backup is abstraction of backup job, it is a collection of backup Files, and has its unique name.

Processor

Usually, when we are doing some backup, we process our backup files (per example - we compress them into one single archive). Processor is defined within RunOpenCode\Backup\Contract\ProcessorInterface and have only one method defined: process(array $files).

Purpose of processor is to somehow modify the collection of files scheduled for backup, and to return the resulting files of that modification.

Backup library currently provides you with several ProcessorInterface implementations:

  • RunOpenCode\Backup\Processor\NullProcessor which is empty implementation of above mentioned interface. It is used for testing purposes, however, it can be used when you do not want to process backup files (per example, for incremental snapshot backups).
  • RunOpenCode\Backup\Processor\GzipArchiveProcessor which compress all backup files into one gzip archive. Requires gzip installed on system, accessible via console.
  • RunOpenCode\Backup\Processor\ZipArchiveProcessor which compress all backup files into one zip archive. Requires zip installed on system, accessible via console.
  • RunOpenCode\Backup\Processor\ProcessorCollection which is collection of several implementations of ProcessorInterface that allows you to do several successive processing activities agains backup files.

Namer

Your backup files will be stored in one directory in your backup storage. Namer will provide a name for that directory. Namers implement RunOpenCode\Backup\Contract\NamerInterface which contains only one method: getName().

Backup library provides you with two default namer implementations:

  • RunOpenCode\Backup\Namer\Constant which will always provide exact same name for your new backup directory.
  • RunOpenCode\Backup\Namer\Timestamp which will provide you with name of directory based on current date and time.

Depending on naming strategy, you can get different results with your backup. With RunOpenCode\Backup\Namer\Constant you can implement incremental backup, snapshot backup, which will behave as rsync Unix utility. With timestamp namer, RunOpenCode\Backup\Namer\Timestamp, each new backup can be stored in new directory.

However, you can configure timestamp namer to use, per example, only day of the week, so you can store only last 7 backups without using rotators.

Nevertheless, it is advise to use namers for defining weather it will be a incremental backup, or complete backup, while rotators should be used for rotations of old backups.

Rotator

Rotator will nominate old backups for removal from backup storage, if some conditions are met. Rotator is defined with RunOpenCode\Backup\Contract\RotatorInterface and have only one method: nominate(array $backups). Rotator can not remove old backups, rotator is not aware of backup storage, his only role in process is to nominate old backups for removal from list of backups.

Backup library provides you with several rotators:

  • RunOpenCode\Backup\Rotator\NullRotator which never nominates any backup for removal. It is used for testing purposes, however, it can be used in your backup process if you want to keep all backups.
  • RunOpenCode\Backup\Rotator\MaxCountRotator will keep up to maximum defined number of backups. If there are more backups than maximum allowed, oldest backups get nominated for removal.
  • RunOpenCode\Backup\Rotator\MaxSizeRotator will keep up to maximum total size of all backups. If size of backups is larger than maximum allowed, oldest backups get nominated for removal.
  • RunOpenCode\Backup\Rotator\MinCountMaxSizeRotator nominates backups for removal using same method as MaxSizeRotator, however, rotator will keep minimum defined number of backups even if maximum size constrain is violated.
  • RunOpenCode\Backup\Rotator\RotatorCollection can be used to aggregate nominations from several different rotators.

Note that default backup workflow within this library defines pre-rotation and post-rotation. Pre-rotation is executed before backup is copied to backup storage (destination), while post-rotation is executed after backup is copied to backup storage.

The reason behind this is that file system operations are not transactional. If removal of old backup is executed prior to pushing new backup to backup storage, and coping fails, you could end up with one backup less as a result of operation. However, if removal of old backup is executed after pushing new backup to backup storage, and coping fails, you would still keep old backups.

Pre and post rotation should support wishes of booth more and/or less conservative system administrator.

Destination

Destination is abstraction of backup storage. Each destination implements RunOpenCode\Backup\Contract\Destination interface which is most complex component in this library and have several responsibilities:

  • Copies backup files from source to backup destination into relevant directory. If that directory is not empty, it will synchronize source files with files in that directory providing the user with possibility to have incremental backups (method: push(BackupInterface $backup)). Directory name should be same as sanitized backup name.
  • Provides getters and hasers for backups and enables iteration trough existing backups (methods: get($name), has($name), all() and implementing interfaces \IteratorAggregate and \Countable).
  • Supports removal of existing backups (method: delete($name)).

Backup library provide you with several default implementations:

  • RunOpenCode\Backup\Destination\NullDestination which is used for testing purposes, but it can be used in production environments in conjunction with events (which will be explained latter on).
  • RunOpenCode\Backup\Destination\LocalDestination which is abstraction of local file system. You can use local destination when backup storage is on mountable device. LocalDestination requires symfony/filesystem to be installed.
  • RunOpenCode\Backup\Destination\FlysystemDestination can be used in conjunction with optional package league/flysystem. You can read more about Flysystem here. In general, Flysystem is abstraction of various storage systems, which includes, but not limited to, Dropbox, Azure, AWS, etc.

Additionally, you are provided with possibility to use multiple destinations for your backups, by using:

  • RunOpenCode\Backup\Destination\DestinationCollection which is collection of several destinations. This will allow you to have redundant copies of your backups. Note that DestinationCollection push() method will fail if any of destination within the collection fails with push() method.
  • RunOpenCode\Backup\Destination\ReplicatedDestination defines master destination and slave destination. Difference between ReplicatedDestination and DestinationCollection is that if slave destination in ReplicatedDestination::push() method fails, backup will not fail, it will be considered as successful.

Note that you can combine ReplicatedDestination and DestinationCollection to achieve various different backup storage systems, from simple ones to very complex.

Workflow

Workflow is abstraction of backup process, a sequence of activities which needs to be undertaken for backup process to be successfully completed.

Workflow is defined with RunOpenCode\Backup\Contract\WorkflowInterface, while workflow activity is defined with RunOpenCode\Backup\Contract\WorkflowActivityInterface. In that matter, you can consider a Workflow as collection of Activities, executed in ordered sequence.

Backup library provides you with default implementation of workflow: RunOpenCode\Backup\Workflow\Workflow with static method build() that will create default workflow with following activities in sequence:

  1. RunOpenCode\Backup\Workflow\Fetch activity in which files for backup are fetched from source.
  2. RunOpenCode\Backup\Workflow\Process activity in which files for backup are processed.
  3. RunOpenCode\Backup\Workflow\Name activity in which backup gets its name.
  4. RunOpenCode\Backup\Workflow\PreRotate activity in which existing old backups on destination are rotated.
  5. RunOpenCode\Backup\Workflow\Push activity in which backup is pushed to destination.
  6. RunOpenCode\Backup\Workflow\PostRotate activity in which existing old backups on destination are rotated.

Note that you can modify this workflow to suit your needs, if provided one is not according to your desired backup workflow. However, this can be considered as edge case.

You should note that default implementation of workflow, RunOpenCode\Backup\Workflow\Workflow depends on Symfony\Component\EventDispatcher\EventDispatcherInterface and Psr\Log\LoggerInterface, as well as provided workflow activities. However, neither workflow, nor its activities, resolves that dependency during the construction process. Workflow will provide EventDispatcher and Logger to the activities prior to their execution via setters, while workflow should be provided with mentioned prior to its execution.

Events

Events and Symfony EventDispatcher are major difference between this library and original kbond/php-backup library. Events which are dispatched within this library and default workflow are defined in RunOpenCode\Backup\Event\BackupEvents while dispatched events are instance of RunOpenCode\Backup\Event\BackupEvent.

Events are used to follow up every defined backup workflow activity which allows you to:

  • Modify and/or filter results of each workflow activity. Per example, you can use RunOpenCode\Backup\Source\NullSource which will return no files for backup, and add files for backup manually by hooking up to BackupEvents::FETCH event. In that matter, every "Null" implementation in this library makes sense and can be used in production in conjunction with EventDispatcher.
  • Release and clean up resources which are not required anymore. Some implementations of this library components requires some kind of cleaning up. Per example, backup of MySQL database requires usage of temporary file, which ought to be cleaned up when backup process is terminated. By hooking up to BackupEvents::TERMINATE event, RunOpenCode\Backup\Source\MySqlDumpSource gets notified when temporary file is not used anymore and can be removed from system.

By using event dispatching, API for backup components is simplified - there is no need for cleanUp() methods.

Important note: some events will be dispatched, and some won't. However, in your application, you can always count on following events:

  • BackupEvents::BEGIN will be dispatched when backup is started for some profile.
  • BackupEvents::TERMINATE will be dispatched when backup is terminated for some profile, regardless of its result of execution. Use this event as indicator when to clean up all used temporary files and to release all resources.

Other events depends on workflow and result of each workflow activity, as well as fact if there were some error in execution.

Profile

Profile is defined with RunOpenCode\Backup\Contract\ProfileInterface while default implementation RunOpenCode\Backup\Backup\Profile is provided. Backup profile defines:

  • Source of files for backup.
  • Processor which will proces those files.
  • Namer which will provide the name for each new backup.
  • Pre and Post rotators which will rotate existing old backups.
  • Destination where backup will be stored.

If you think about your project, application which you want to backup, profiles for your application would be, per example:

  • Hourly snapshot - profile would be executed every hour.
  • Daily backup - profile would be executed every day.
  • Weekly backup - profile would be executed every week.
  • ...

Manager

Manager is defined with RunOpenCode\Backup\Contract\ManagerInterface, default implementation is given with RunOpenCode\Backup\Manager. He holds references to all profiles, allows iteration trough profiles, and their execution. If you are using dependency injection or service locator in your project, Manager should be only one public entry point into library, while other components should be injected into manager as hidden/private dependencies.

Notes on EventDispatcher, Logger and throwing exceptions

Note that some of the components in library depends on event dispatcher and/or logger. However, dependency is not provided via constructor, it is provided via setters. Some of the components do depend on dispatcher and/or logger, some don't.

In order to identify weather some class depends on dispatcher you can investigate if that class implements RunOpenCode\Backup\Contract\EventDispatcherAwareInterface, while logger dependency can be investigated by checking if RunOpenCode\Backup\Contract\LoggerAwareInterface is implemented.

Instances of RunOpenCode\Backup\Contract\WorkflowInterface and RunOpenCode\Backup\Contract\WorkflowActivityInterface depends on logger and dispatcher by design. They will log about progress of backup process and dispatch backup progress events.

Some other classes within this library depends on event dispatcher in order to clean up temporary files and to release resources.

However, do note that by design it is intended for workflow and its activities to log and to dispatch events. Other components should subscribe to events only. If they have to notify about error - they should throw exception.

Logger and Event Dispatcher traits

To simplify your implementation, when implementing RunOpenCode\Backup\Contract\EventDispatcherAwareInterface and RunOpenCode\Backup\Contract\LoggerAwareInterface, please note that

  • RunOpenCode\Backup\Event\EventDispatcherAwareTrait
  • RunOpenCode\Backup\Log\LoggerAwareTrait

are at your disposal.

Extending the library

Do you need your own source, destination, processor? You can easily extend the library.

Implementing your own source

Your class needs to implement RunOpenCode\Backup\Contract\SourceInterface. Method fetch() should return collection of files RunOpenCode\Backup\Contract\File for backup.

Note that each file has its path and relative path. Path is absolute path to file, so backup library can access to it and copy it to the backup destination. However, within backup directory, file will be saved under relative path. Relative path is determined by root path of file.

Implementing your own processor

Your class needs to implement RunOpenCode\Backup\Contract\ProcessorInterface with method process(array $files). You will get an collection of files that needs to be backed up. Your processor should do something with those files, and return collection of files that should be backed up after processing.

Implementing your own rotator

Your class needs to implement RunOpenCode\Backup\Contract\RotatorInterface. Rotator will get collection of backups on backup destination and should only nominate which backups should be removed.

Implementing your own destination

Your class needs to implement RunOpenCode\Backup\Contract\Destination. Destination is collection of RunOpenCode\Backup\Contract\BackupInterface, while it needs to be noted that physically, for each backup, destination will create a directory and store all backup files within that directory.

When implementing method push(BackupInterface $backup) destination should support creating new backups, as well as maintaining incremental backups. That means that if backup directory exists on destination, on push, destination should sync source files with files that exists in backup directory. To speed up implementation, RunOpenCode\Backup\Destination\BaseDestination is at your disposal.

This library is licensed under MIT license, same license as original library. For original library license, please visit: https://github.com/kbond/php-backup/blob/master/LICENSE.

For license of this library, see LICENSE file distributed with this package.