detect bouncing status and send warning email

README.md

 # Monitoring - Webapp
 
 
-## Installation
+## Contributing
 
-Requires PHP mongodb extension:
+To run this tool localy, you will need:
 
-https://docs.mongodb.com/ecosystem/drivers/php/
-https://pecl.php.net/package/mongodb
+### Mongodb server
+
+```
+sudo apt-get install mongodb
+```
+
+On Ubuntu 16.04, this will install mongodb version 2.6 by default.
+
+### Mongodb PHP extension
+
+* https://docs.mongodb.com/ecosystem/drivers/php/
+* https://pecl.php.net/package/mongodb
+
+With mongodb 2.6, you will need mongodb-1.4.4:
 
 ```
 sudo pecl install mongodb-1.4.4
 ```
 
+### PHP
+
+The extension mongodb-1.4.4 is compatible with PHP 7.2 or less (thus NOT with PHP 7.3).
+
+If you try with PHP7.3, you will encounter errors like
+
+```
+PHP symbol lookup error: /usr/lib/php/20180731/mongodb.so: undefined symbol: ZEND_HASH_GET_APPLY_COUNT
+```
+
+You can find the complete compatibility matrix at https://docs.mongodb.com/ecosystem/drivers/php/
+
+### Installation
+
 ```
 composer install
 touch storage/app/db.sqlite
@@ -20,9 +46,9 @@ php artisan migrate
 php artisan key:generate
 ```
 
-## Fronted
+### Fronted
 
 ```
 npm install
 npm run watch
-```
\ No newline at end of file
+```

app/Jobs/StatusChangeDetection.php

@@ -12,7 +12,6 @@ use Illuminate\Queue\SerializesModels;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use Illuminate\Foundation\Bus\Dispatchable;
-use Illuminate\Support\Facades\Mail;
 
 class StatusChangeDetection implements ShouldQueue
 {
@@ -62,18 +61,40 @@ class StatusChangeDetection implements ShouldQueue
         $this->sendNotificationIfRequired($change);
     }
 
+    /**
+     * Maximum number of notifications sent per day.
+     */
+    const NOTIFICATIONS_PER_DAY = 4;
+
     public function sendNotificationIfRequired(StatusChange $change)
     {
         $server = $change->server();
+        $server_id = $server->id;
 
-        $notification = new Notification();
-        $notification->server()->associate($server);
-        $notification->type = "change";
-        $notification->change_id = $change->id;
-        $notification->save();
+        $onedayago = time() - 24 * 3600;
+        $sent_notifications_count = Notification::findForServer($server_id, $onedayago)->count();
 
-        foreach ($server->organization->users as $user) {
-            Mail::to($user)->send(new \App\Mail\StatusChanged($change));
+        if ($sent_notifications_count < self::NOTIFICATIONS_PER_DAY) {
+            $notification = new Notification();
+            $notification->server()->associate($server);
+            $notification->type = "change";
+            $notification->change_id = $change->id;
+            $notification->saveAndSend();
+
+            return;
         }
+
+        if ($sent_notifications_count == self::NOTIFICATIONS_PER_DAY) {
+            $notification = new Notification();
+            $notification->server()->associate($server);
+            $notification->type = "bouncing";
+            $notification->change_id = $change->id;
+            $notification->saveAndSend();
+
+            return;
+        }
+
+        // nothing to do if number of sent notifications > COUNT
+
     }
 }

app/Mail/StatusBouncing.php

+<?php
+
+namespace App\Mail;
+
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Queue\SerializesModels;
+
+class StatusBouncing extends Mailable
+{
+    use Queueable, SerializesModels;
+
+    private $change;
+
+    /**
+     * Create a new message instance.
+     *
+     * @return void
+     */
+    public function __construct(\App\StatusChange $change)
+    {
+        $this->change = $change;
+    }
+
+    /**
+     * Build the message.
+     *
+     * @return $this
+     */
+    public function build()
+    {
+        return $this->markdown('emails.server.bouncing')
+                ->with(["change" => $this->change])
+                ->from("monitor@web-d.be")
+                ->subject(
+                    $this->change->server()->organization->name . " / "
+                    . $this->change->server()->name . " : Status bouncing"
+                );
+    }
+}

app/Notification.php

@@ -3,6 +3,7 @@
 namespace App;
 
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Facades\Mail;
 
 class Notification extends Model
 {
@@ -15,5 +16,29 @@ class Notification extends Model
         return $this->belongsTo('\App\Server');
     }
 
+    public function saveAndSend()
+    {
+        $this->save();
+        $change = $this->change();
+
+        $mail = new \App\Mail\StatusChanged($change);
+        if ($this->type == "bouncing") {
+            $mail = new \App\Mail\StatusBouncing($change);
+        }
 
+        foreach ($this->server->organization->users as $user) {
+            Mail::to($user)->send($mail);
+        }
+    }
+
+    public function change() : StatusChange
+    {
+        return StatusChange::find($this->change_id);
+    }
+
+    public static function findForServer(int $server_id, int $since = 0)
+    {
+        return self::where('server_id', $server_id)
+                ->where('created_at', '>', $since);
+    }
 }

app/StatusChange.php

@@ -83,6 +83,18 @@ class StatusChange
         return $changes;
     }
 
+    public static function find(string $id) : StatusChange
+    {
+        $collection = \Mongo::get()->monitoring->statuschanges;
+        $result = $collection->findOne(
+                ['_id' => new \MongoDB\BSON\ObjectId($id)]);
+
+        $status = new StatusChange();
+        $status->parse($result);
+        $status->id = $id;
+        return $status;
+    }
+
     public static function getLastChangeForServer(int $server_id) : StatusChange
     {
         $collection = \Mongo::get()->monitoring->statuschanges;

database/migrations/2019_06_17_074713_create_notifications_table.php

@@ -15,9 +15,9 @@ class CreateNotificationsTable extends Migration
     {
         Schema::create('notifications', function (Blueprint $table) {
             $table->increments('id');
-            $table->unsignedInteger('created_at');
-            $table->unsignedInteger('updated_at');
-            $table->unsignedInteger('server_id');
+            $table->integer('created_at');
+            $table->integer('updated_at');
+            $table->integer('server_id');
             $table->string('change_id');
             $table->string('type');
         });

resources/views/emails/server/bouncing.blade.php

+@component('mail::message')
+# {{ $change->server()->organization->name }} / {{ $change->server()->name }} : status bouncing
+
+Your server **{{ $change->server()->organization->name }} / {{ $change->server()->name }}**
+seems to be bouncing between different states.
+
+This is our last email for today...
+
+{{ action("ServerController@show", ["server" => $change->server()]) }}
+
+
+{{ config('app.name') }}
+@endcomponent

tests/Unit/ExampleTest.php

@@ -3,6 +3,7 @@
 namespace Tests\Unit;
 
 use App\User;
+use App\Notification;
 use App\Organization;
 use App\Sensor\Disks;
 use App\Sensor\Ifconfig;
@@ -191,5 +192,21 @@ class ExampleTest extends TestCase
             $server->status(),
             $last_change->status
         );
+
+        // Check if a notification were inserted
+        $this->assertTrue(Notification::findForServer($server_id)->count() > 0);
+
+        // Insert multiple status changes to simulate bouncing
+
+        for ($i = 0; $i < 4; $i++) {
+            $change = new \App\StatusChange();
+            $change->status = 155;
+            $change->server_id = $server_id;
+            $change->save();
+
+            // Run change detection
+            $change_detection_job = new \App\Jobs\StatusChangeDetection();
+            $change_detection_job->detectChangeForServer($server);
+        }
     }
 }