…gh a server dumper (ogizanagi, nicolas-grekas)This PR was merged into the 4.1-dev branch.Discussion----------[VarDumper] Introduce a new way to collect dumps through a server dumper| Q             | A| ------------- | ---| Branch?       | 4.1 <!-- see comment below -->| Bug fix?      | no| New feature?  | yes <!-- don't forget updating src/**/CHANGELOG.md files -->| BC breaks?    | no| Deprecations? | no <!-- don't forget updating UPGRADE-*.md files -->| Tests pass?   | yes| Fixed tickets |#22987 <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | todo <!--highly recommended for new features-->Could also be interesting as alternate solution for#23442.Inspired by the [`ServerLogHandler`](#21080) and@nicolas-grekas's [comment](#22987 (comment)) in#22987.---## DescriptionThis PR introduces a new `server:dump` command available in the `VarDumper` component.Conjointly with a new `ServerDumper` data dumper, it allows to send serialized `Data` clones to a single centralized server, in charge of dumping them on CLI output, or in an file in HTML format.## Showcase### HTTP callsFor instance, when working on an API and dumping something, you might end up with a mix of your response and the CLI dumped version of the data you asked:```phpclass HelloController extends AbstractController{    /**     *@route("/hello")     */    public function hello(Request $request, UserInterface $user)    {        dump($request->attributes, $user);        return JsonResponse::create([            'status' => 'OK',            'message' => "Hello {$user->getUsername()}"        ]);    }}```<img width="732" alt="screenshot 2017-08-08 a 16 44 24" src="https://user-images.githubusercontent.com/2211145/29077731-0b2152d6-7c59-11e7-99dd-2d060a906d48.PNG">You might even get the HTML dump version [under some conditions](https://github.com/symfony/symfony/blob/master/src/Symfony/Component/HttpKernel/DataCollector/DumpDataCollector.php#L146-L157).Dumping to a server allows collecting dumps in a separate place:<!--![server-dumper-http-to-cli-output](https://user-images.githubusercontent.com/2211145/29077977-8ace19ce-7c59-11e7-998e-ee9c49e67958.gif)-->![server-dump-http-to-cli](https://user-images.githubusercontent.com/2211145/29226044-dcc95f12-7ed0-11e7-8343-40aeb7b18dd5.gif)~⚠️ By swallowing the previous dumpers output, the dump data collector is not active when running the dump server. Disable swallowing if you want both.~ ➜ Dumps are still collected in the profiler thanks tof24712e### CLI callsThe best probably is (to me) that you can also debug CLI applications...![server-dump-cli](https://user-images.githubusercontent.com/2211145/29225951-84e29098-7ed0-11e7-8067-abaa9c50d169.gif)<!--![server-dumper-cli-to-cli-output](https://user-images.githubusercontent.com/2211145/29078261-1eb950ea-7c5a-11e7-94ee-aa3ae3bf7fb0.gif)-->...and get HTML formatted dumps:![server-dumper-cli-to-html-output](https://user-images.githubusercontent.com/2211145/30784609-d7dc19b8-a158-11e7-9b11-88ae819cfcca.gif)<!--![server-dump-cli-to-html](https://user-images.githubusercontent.com/2211145/29225866-2b5675e4-7ed0-11e7-98eb-339611bd94a7.gif)--><!--![server-dumper-cli-to-html-output](https://user-images.githubusercontent.com/2211145/29078247-17e33e5c-7c5a-11e7-94f7-47de6774e0e8.gif)-->hence, benefit from all the features of this format (collapse, search, ...)### HTML output at a glance<img width="831" alt="screenshot 2017-08-11 a 19 28 25" src="https://user-images.githubusercontent.com/2211145/29225513-eae349f2-7ece-11e7-9861-8cda9e80ba7f.PNG">The HTML output benefits from all the `HtmlDumper` features and contains extra informations about the context (sources, requests, command line, ...). It doesn't aim to replace the profiler for HTTP calls with the framework, but is really handy for CLI apps or by wiring it in your own web app, out of the framework usage.### CLI output at a glance<img width="829" alt="screenshot 2017-08-11 a 19 52 57" src="https://user-images.githubusercontent.com/2211145/29225482-c24afe18-7ece-11e7-8e83-d019b0d8303e.PNG">## Usage within the framework### ConfigFor instance, in your `config_dev.yml`:```yml#config_dev.ymldebug:    server_dump: true```or in your `config.yml`:```yml#config.ymldebug:    server_dump: '%kernel.debug%'```~~The configuration also allows to set a `host` option, but there is already a sensible default value (`tcp://0.0.0.0:9912`) so you don't have to deal with it.~~ Sinceb002175, in case you want to change the default host value used, simply use the `VAR_DUMPER_SERVER` env var.When the server is running, all dumps are collected by the server and previous dumpers ones are "swallowed" ~~by default. If you want both to collect dumps on the server AND keep previous dumpers on regular outputs, you can disable swallowing:~~<!--```ymldebug:    server_dump:        swallow: false```-->When the server isn't running or in case of failure to send the data clones to the server, the server dumper will delegates to the configured wrapped dumper, so dumps are displayed and collected as usual.### Running the server```bashbin/console server:dump [--format=cli|html]```#### Options- ~~The `output` option defaults to `null` which will display dumps on CLI. It accepts a file path in which dumps will be collected in HTML format.~~- The `format` option allows to switch format to use. For instance, use the `html` format and redirect the output to a file in order to open it in your browser and inspect dumps in HTML format.- ~~The default `host` value is the same as the one configured under the `debug.server_dump.host` config option, so you don't have to deal with it in most cases.~~    Sinceb002175, in case you want to change the default host value used, simply use the `VAR_DUMPER_SERVER` env var:    ```bash    VAR_DUMPER_SERVER=0.0.0.0:9204 bin/console server:dump    ```## Manual wiringIf you want to wire it yourself in your own project or using it to inspect dumps as html before the kernel is even boot for instance:```php$host = 'tcp://0.0.0.0:9912'; // use null to read from the VAR_DUMPER_SERVER env var$cloner = new VarCloner();$dumper = new ServerDumper($host, new CliDumper());VarDumper::setHandler(function ($var) use ($dumper, $cloner) {    $dumper->dump($cloner->cloneVar($var));});```## Create your own server appThe component already provides a default server app by means of the `ServerDumpCommand`, but you could also build your own by using the `DumpServer`:```php$host = 'tcp://0.0.0.0:9912'; // use null to read from the VAR_DUMPER_SERVER env var$server = new DumpServer($host);$server->start();$server->listen(function (Data $data, array $context, $clientId) {    // do something});```Commits-------138dad6 [VarDumper] Some tweaks after Nicolas' commit & ServerDumperPlaceholderCommand088c52e [VarDumper] Review config to use debug.dump_destination & tweak data collector3db1404 [VarDumper] Introduce a new way to collect dumps through a server dumper

… at any time (ogizanagi)This PR was merged into the 4.1-dev branch.Discussion----------[VarDumper] Provide binary, allowing to start a server at any timeas soon as the "symfony/var-dumper" & "symfony/console" components are available.| Q             | A| ------------- | ---| Branch?       | master <!-- see below -->| Bug fix?      | no| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets | N/A   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | TODOsymfony/symfony-docs#9474Now that#23831 is merged, there is still room for improvements we can bring during the stabilization months.Here is a first one: providing a simple CLI binary allows to easily start a server from any project (or even globally), just by having the var dumper & console packages in your deps.Commits-------eef10b1 [VarDumper] Provide binary, allowing to start a server at any time