Merge branch 'zero_downtime' into dev

# Conflicts:
#	src/Console/Features/requiresModelArgument.php
#	src/ElasticEngine.php

Author: babenkoivan

README.md

@@ -3,8 +3,13 @@
 [![Packagist](https://img.shields.io/packagist/v/babenkoivan/scout-elasticsearch-driver.svg)](https://packagist.org/packages/babenkoivan/scout-elasticsearch-driver)
 [![Packagist](https://img.shields.io/packagist/dt/babenkoivan/scout-elasticsearch-driver.svg)](https://packagist.org/packages/babenkoivan/scout-elasticsearch-driver)
 [![Gitter](https://img.shields.io/gitter/room/nwjs/nw.js.svg)](https://gitter.im/scout-elasticsearch-driver/Lobby)
+[![Donate](https://img.shields.io/badge/donate-PayPal-blue.svg)](https://www.paypal.me/ivanbabenko)
 
-:exclamation: The project has a [chat room](https://gitter.im/scout-elasticsearch-driver/Lobby) on Gitter!
+:coffee: If you like my package, it'd be nice of you [to buy me a cup of coffee](https://www.paypal.me/ivanbabenko).
+ 
+:octocat: The project has a [chat room on Gitter](https://gitter.im/scout-elasticsearch-driver/Lobby)!
+
+---
 
 This package offers advanced functionality for searching and filtering data in Elasticsearch.
 Check out its [features](#features)!
@@ -22,6 +27,7 @@ Check out its [features](#features)!
 * [Console commands](#console-commands)
 * [Search rules](#search-rules)
 * [Available filters](#available-filters)
+* [Zero downtime migration](#zero-downtime-migration)
 * [Debug](#debug)
 
 ## Tutorial
@@ -36,6 +42,7 @@ There are information about Elasticsearch installation and the package usage exa
 * A possibility to add a new field to an existing mapping [automatically](#configuration) or using [the artisan command](#console-commands).
 * Lots of different ways to implement your search algorithm: using [search rules](#search-rules) or a [raw search](#usage).
 * [Various filter types](#available-filters) to make a search query more specific.
+* [Zero downtime migration](#zero-downtime-migration) from an old index to a new index.
 
 ## Requirements
 
@@ -257,6 +264,7 @@ elastic:create-index | `index-configurator` - The index configurator class | Cre
 elastic:update-index | `index-configurator` - The index configurator class | Updates settings and mappings of an Elasticsearch index.
 elastic:drop-index | `index-configurator` - The index configurator class | Drops an Elasticsearch index.
 elastic:update-mapping | `model` - The model class | Updates a model mapping.
+elastic:migrate | `model` - The model class, `target-index` - The index name to migrate | Migrates model to another index.
 
 For detailed description and all available options run `php artisan help [command]` in the command line.
 
@@ -371,6 +379,29 @@ whereRegexp($field, $value, $flags = 'ALL') | whereRegexp('name.raw', 'A.+') | F
 
 In most cases it's better to use raw fields to filter records, i.e. not analyzed fields.
 
+## Zero downtime migration
+
+As you might know, you can't change the type of already created field in Elasticsearch. 
+The only choice in such case is to create a new index with necessary mapping and import your models into the new index.      
+A migration can take quite a long time, so to avoid downtime during the process the driver reads from the old index and writes to the new one.
+As soon as migration is over it starts reading from the new index and removes the old index.
+This is how the artisan `elastic:migrate` command works.  
+
+Before you run the command, make sure that your index configurator uses the `ScoutElastic\Migratable` trait.
+If it's not, add the trait and run the artisan `elastic:update-index` command using your index configurator class name as an argument:
+
+```php
+php artisan elastic:update-index App\\MyIndexConfigurator
+```
+
+When you are ready, make changes in the model mapping and run the `elastic:migrate` command using the model class as the first argument and desired index name as the second argument:
+
+```php
+php artisan elastic:migrate App\\MyModel my_index_v2
+``` 
+
+Note, that if you need just to add new fields in your mapping, use the `elastic:update-mapping` command.
+
 ## Debug
 
 There are two methods that can help you to analyze results of a search query:

src/Console/ElasticIndexCreateCommand.php

@@ -5,6 +5,7 @@
 use Illuminate\Console\Command;
 use ScoutElastic\Console\Features\requiresIndexConfiguratorArgument;
 use ScoutElastic\Facades\ElasticClient;
+use ScoutElastic\Migratable;
 use ScoutElastic\Payloads\IndexPayload;
 
 class ElasticIndexCreateCommand extends Command
@@ -15,11 +16,9 @@ class ElasticIndexCreateCommand extends Command
 
     protected $description = 'Create an Elasticsearch index';
 
-    public function handle()
+    protected function createIndex()
     {
-        if (!$configurator = $this->getIndexConfigurator()) {
-            return;
-        }
+        $configurator = $this->getIndexConfigurator();
 
         $payload = (new IndexPayload($configurator))
             ->setIfNotEmpty('body.settings', $configurator->getSettings())
@@ -30,8 +29,37 @@ public function handle()
             ->create($payload);
 
         $this->info(sprintf(
-            'The index %s was created!',
+            'The %s index was created!',
             $configurator->getName()
         ));
     }
+
+    protected function createWriteAlias()
+    {
+        $configurator = $this->getIndexConfigurator();
+
+        if (!in_array(Migratable::class, class_uses_recursive($configurator))) {
+            return;
+        }
+
+        $payload = (new IndexPayload($configurator))
+            ->set('name', $configurator->getWriteAlias())
+            ->get();
+
+        ElasticClient::indices()
+            ->putAlias($payload);
+
+        $this->info(sprintf(
+            'The %s alias for the %s index was created!',
+            $configurator->getWriteAlias(),
+            $configurator->getName()
+        ));
+    }
+
+    public function handle()
+    {
+        $this->createIndex();
+
+        $this->createWriteAlias();
+    }
 }

src/Console/ElasticIndexDropCommand.php

@@ -17,9 +17,7 @@ class ElasticIndexDropCommand extends Command
 
     public function handle()
     {
-        if (!$configurator = $this->getIndexConfigurator()) {
-            return;
-        }
+        $configurator = $this->getIndexConfigurator();
 
         $payload = (new IndexPayload($configurator))
             ->get();

src/Console/ElasticIndexUpdateCommand.php

@@ -2,11 +2,14 @@
 
 namespace ScoutElastic\Console;
 
+use Exception;
+use LogicException;
 use Illuminate\Console\Command;
 use ScoutElastic\Console\Features\requiresIndexConfiguratorArgument;
 use ScoutElastic\Facades\ElasticClient;
-use Exception;
+use ScoutElastic\Migratable;
 use ScoutElastic\Payloads\IndexPayload;
+use ScoutElastic\Payloads\RawPayload;
 
 class ElasticIndexUpdateCommand extends Command
 {
@@ -16,23 +19,19 @@ class ElasticIndexUpdateCommand extends Command
 
     protected $description = 'Update settings and mappings of an Elasticsearch index';
 
-    public function handle()
+    protected function updateIndex()
     {
-        if (!$configurator = $this->getIndexConfigurator()) {
-            return;
-        }
+        $configurator = $this->getIndexConfigurator();
 
         $indexPayload = (new IndexPayload($configurator))->get();
 
         $indices = ElasticClient::indices();
 
         if (!$indices->exists($indexPayload)) {
-            $this->error(sprintf(
+            throw new LogicException(sprintf(
                 'Index %s doesn\'t exist',
                 $configurator->getName()
             ));
-
-            return;
         }
 
         try {
@@ -67,4 +66,42 @@ public function handle()
             $configurator->getName()
         ));
     }
+
+    protected function createWriteAlias()
+    {
+        $configurator = $this->getIndexConfigurator();
+
+        if (!in_array(Migratable::class, class_uses_recursive($configurator))) {
+            return;
+        }
+
+        $indices = ElasticClient::indices();
+
+        $existsPayload = (new RawPayload())
+            ->set('name', $configurator->getWriteAlias())
+            ->get();
+
+        if ($indices->existsAlias($existsPayload)) {
+            return;
+        }
+
+        $putPayload = (new IndexPayload($configurator))
+            ->set('name', $configurator->getWriteAlias())
+            ->get();
+
+        $indices->putAlias($putPayload);
+
+        $this->info(sprintf(
+            'The %s alias for the %s index was created!',
+            $configurator->getWriteAlias(),
+            $configurator->getName()
+        ));
+    }
+
+    public function handle()
+    {
+        $this->updateIndex();
+
+        $this->createWriteAlias();
+    }
 }