PHP & Web Development Blogs

Today I am going write a blog on how to Monitor Memory and Disk custom metrics and creating alarm in Ubuntu.

To do this, we can use Amazon CloudWatch, which provides a flexible, scalable and reliable solution for monitoring our server.

Amazon Cloud Watch will allow us to collect the custom metrics from our applications that we will monitor to troubleshoot any issues, spot trends, and configure operational performance. CloudWatch functions display alarms, graphs, custom metrics data and including statistics.

Installing the Scripts

Before we start installing the scripts for monitoring, we should install all the dependent packages need to perform on Ubuntu.

First login to your AWS server, and from our terminal, install below packages

sudo apt-get update
sudo apt-get install unzip
sudo apt-get install libwww-perl libdatetime-perl

Now Install the Monitoring Scripts

Following are the steps to download and then unzip we need to configure the Cloud Watch Monitoring scripts on our server:
1. In the terminal, we need to change our directory and where we want to add our monitoring scripts.
2. Now run the below command and download the source:

curl https://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.2.zip -O

3. Now uncompress the currently downloaded sources using the following commands

unzip CloudWatchMonitoringScripts-1.2.2.zip && \

rm CloudWatchMonitoringScripts-1.2.2.zip && \

cd aws-scripts-mon

The directory will contain Perl scripts, because of the execution of these scripts only report memory run and disk space utilization metrics will run in our Ubuntu server.
Currently, our folder will contain the following files:
mon-get-instance-stats.pl - This Perl file is used to displaying the current utilization statistics reports for our AWS instance on which these file scripts will be executed.
mon-put-instance-data.pl - This Perl script file will be used for collecting the system metrics on our ubuntu server and which will send them to the Amazon Cloud Watch.
awscreds.template - This Perl script file will contain an example for AWS credentials keys and secret access key named with access key ID.
CloudWatchClient.pm - This Perl script file module will be used to simplify by calling Amazon Cloud Watch from using other scripts.
LICENSE.txt – This file contains the license details for Apache 2.0.
NOTICE.txt – This file contains will gives us information about Copyright notice.
4. For performing the Cloud Watch operations, we need to confirm that whether our scripts have corresponding permissions for the actions:

If we are associated with an IAM role with our EC2 Ubuntu instance, we need to verify that which will grant the permissions to perform the below-listed operations:

cloudwatch:GetMetricStatistics

cloudwatch:PutMetricData

ec2:DescribeTags

cloudwatch:ListMetrics

Now we need to copy the ‘awscreds.template’ file into ‘awscreds.conf’ by using the command below and which will update the file with details of the AWS credentials.

cp awscreds.template awscreds.conf

AWSAccessKeyId = my_access_key_id

AWSSecretKey = my_secret_access_key

Now we completed the configuration.

mon-put-instance-data.pl

This Perl script file will collect memory, disk space utilization data and swap the current system details and then it makes handling a remote call to Amazon Cloud Watch to reports details to the collected cloud watch data as a custom metrics.

We can perform a simple test run, by running the below without sending data to Amazon CloudWatch

./mon-put-instance-data.pl --mem-util --verify --verbose

Now we are going to set a cron for scheduling our metrics and we will send them to Amazon CloudWatch
1. Now we need to edit the crontab by using below command:

 crontab -e

2. Now we will update the file using the following query which will disk space utilization and report memory for particular paths to Amazon CloudWatch in every five minutes:

*/5 * * * * ~/STORAGE/cloudwatch/aws-scripts-mon/mon-put-instance-data.pl --mem-util --mem-avail --mem-used --disk-space-util --disk-space-avail --disk-space-used --disk-path=/ --disk-path=/STORAGE --from-cron

If there is an error, the scripts will write an error message in our system log.

Use of Options

--mem-used
The above command will collect the information about used memory and which will send the details of the reports in MBs into the MemoryUsed metrics. This will give us information about the metric counts memory allocated by applications and the OS as used.
--mem-util
The above command will collect the information about memory utilization in percentages and which will send the details of the Memory Utilization metrics and it will count the usage of the memory applications and the OS.
--disk-space-util
The above command will collect the information to collect the current utilized disk space and which will send the reports in percentages to the DiskSpaceUtilization for the metric and for the selected disks.
--mem-avail
The above command will collect the information about the available memory and which will send the reports in MBs to the MemoryAvailable metrics details. This is the metric counts memory allocated by the applications and the OS as used.
--disk-path=PATH
The above command will collect the information and will point out the which disk path to report disk space.
--disk-space-avail
The above command will collect the information about the available disk space and which will send the reports in GBs to the DiskSpaceAvailable metric for the selected disks.
--disk-space-used
The above command will collect the information about the disk space used and which will send the reports in GBs to the DiskSpaceUsed metric for the selected disks.

The PATH can specify to point or any of the files can be located on which are mounted point for the filesystem which needs to be reported.

If we want to points to the multiple disks, then specify both of the disks like below:

--disk-path=/ --disk-path=/home

Setting an Alarm for Custom Metrics

Before we are going to running our Perl Scripts, then we need to create an alarm that will be listed in our default metrics except for the custom metrics. You can see some default metrics are listed in below image:



Once we completed setting the cron, then the custom metrics will be located in Linux System Metrics.

Now we are going to creating the alarm for our custom metrics
1. We need to open the cloudwatch console panel at https://console.aws.amazon.com/cloudwatch/home
2. Now navigate to the navigation panel, we need to click on Alarm and we can Create Alarm.
3. This will open a popup which with the list of the CloudWatch metrics by category.
4. Now click on the Linux System Metrics . This will be listed out with custom metrics you can see in the below pictures






5. Now we need to select metric details and we need to click on the NEXT button. Now we need to navigate to Define Alarm step.



6. Now we need to define an Alarm with required fields

Now we need to enter the Alarm name for identifying them. Then we need to give a description of our alarm.

Next, we need to give the condition with the maximum limit of bytes count or percentage when it notifies the alarm. If the condition satisfies, then the alarm will start trigger.

We need to provide a piece of additional information about for our alarm.

We need to define what are the actions to be taken when our alarm changes it state.

We need to select or create a new topic with emails needed for sending notification about alarm state.
7. Finally, we need to choose the Create Alarm.

So its completed. Now the alarm is created for our selected custom metrics.

Finished!

Now the alarm will be listed out under the selected state in our AWS panel. Now we need to select an alarm from the list seen and we can see the details and history of our alarm.

Models and controllers are one of the most essential programming handlers in the Laravel MVC framework, and both are used vastly for different functional operations. Models in Laravel are created inside the app folder and are mostly used to interact with the database using Eloquent ORM, while the controllers are located inside the directory App/Http/Controllers.

As a programmer, you should have the knowledge how to keep the balance in between the programming usage of Models and controllers. As which one should be more utilized for allowing functional tasks in applications deployed on any PHP MySQL hosting.

What is the Concept of Thin Controller and FAT Models

The concept of the thin controller and fat model is that we do less work in our controllers and more work in our models. Like we use our controllers to validate our data and then pass it to the models. While in models, we define our actual functional logic and main coding operations of the desired application. This code structuring process is also a very basic concept of MVC and also the differentiating factor from the conventional complex programming which we mistakenly ignore sometimes.

Why FAT Controllers Are Bad For Handling Code

Controllers are always meant to be defined short and concise, and it should only be used for receiving requests and return responses to it. Anything else further should be programmed in Models, which is actually made for main functional operations.

Placing functional logic in controllers can be bad for many reasons for your applications deployed on anyhosting for PHP. As it not only makes code structure long but also makes it complex sometimes. Further placing code in Controllers is also not recommended because if same functionality is needed somewhere else in route, then pulling out the whole code from their becomes difficult and so its reusability in the application.

Though Laravel is an MVC framework while developing on laravel, we sometimes ignore this and write mostly all our code including the extending of App\Model and all our functional logic in controller route methods. What we can do here is we can create a sub model of our parent model. For example, our parent model is User then we can create another sub model of username in CustomerModel if you are using the same User model for all types of users. In this model, we will write all the logic related to user type Customer.

So now let's take an example of my existing blog creating comment system with laravel and vuejs. In that article, you can see I have made so much mess in my controller methods. Mostly, I have written all my comments logic in my methods, so to shorten that let's clean them in this article. Inside app folder, I will create a new file with name CommentModel.php. Inside this file, I will write my whole logic for comment functions. This is my basic file:

<?php
namespace App;

use App\Comment;
use App\CommentVote;
use App\CommentSpam;
use App\User;
use Auth;

class CommentModel
{


}

?>

Right now it contains no function but has the reference of all my models which I required for this model. Let's first add a function namedgetallcomments passing$pageId as a parameter inside it. The function will get all the comments for the given page:

public function getAllComments($pageId)
 {
 $comments = Comment::where('page_id',$pageId)->get();

 $commentsData = [];


 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();


 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }


 if(sizeof($replies) > 0){
 $reply = 1;
 }

 if(!$spam){
 array_push($commentsData,[
 "name" => $name,
 "photo_url" => (string)$photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" =>$vote,
 "vote" =>$voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString()
 ]);
 } 


 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

Now I will create another function namedreplies which takes$commentId as a parameter. The function is more or less programmed in the same manner as the upper function get all comments.

protected function replies($commentId)
 {
 $comments = Comment::where('reply_id',$commentId)->get();
 $replies = [];



 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0; 


 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();

 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }
 if(!$spam){


 array_push($replies,[
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString()
 ]);
 }




 }


 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

Now lets create a functioncreate comment which passes$array as a parameter in it:

public function createComment($arary)
 {
 $comment = Comment::create($array);


 if($comment)
 return [ "status" => "true","commentId" => $comment->id ];
 else
 return [ "status" => "false" ]; 
 }

Similarly, Now I will create all the function for comment in myCommentModel, so that all the functions gets accumulated in one model.

<?php
namespace App;

use App\Comment;
use App\CommentSpam;
use App\CommentVote;
use App\User;
use Auth;

class CommentModel
{
 public function getAllComments($pageId)
 {
 $comments = Comment::where('page_id', $pageId)->get();

 $commentsData = [];

 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if (Auth::user()) {
 $voteByUser = CommentVote::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();

 if ($voteByUser) {
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if ($spamComment) {
 $spam = 1;
 }
 }

 if (sizeof($replies) > 0) {
 $reply = 1;
 }

 if (!$spam) {
 array_push($commentsData, [
 "name" => $name,
 "photo_url" => (string) $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString(),
 ]);
 }

 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

 protected function replies($commentId)
 {
 $comments = Comment::where('reply_id', $commentId)->get();
 $replies = [];

 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0;

 if (Auth::user()) {
 $voteByUser = CommentVote::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id', $key->id)->where('user_id', Auth::user()->id)->first();

 if ($voteByUser) {
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if ($spamComment) {
 $spam = 1;
 }
 }
 if (!$spam) {

 array_push($replies, [
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString(),
 ]);
 }

 }

 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

 public function createComment($arary)
 {
 $comment = Comment::create($array);

 if ($comment) {
 return ["status" => "true", "commentId" => $comment->id];
 } else {
 return ["status" => "false"];
 }

 }

 public function voteComment($commentId, $array)
 {
 $comments = Comment::find($commentId);
 $data = [
 "comment_id" => $commentId,
 'vote' => $array->vote,
 'user_id' => $array->users_id,
 ];

 if ($array->vote == "up") {
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote++;
 $comments->votes = $vote;
 $comments->save();
 }

 if ($array->vote == "down") {
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote--;
 $comments->votes = $vote;
 $comments->save();
 }

 if (CommentVote::create($data)) {
 return true;
 }

 }

 public function spamComment($commentId, $array)
 {
 $comments = Comment::find($commentId);

 $comment = $comments->first();
 $spam = $comment->spam;
 $spam++;
 $comments->spam = $spam;
 $comments->save();

 $data = [
 "comment_id" => $commentId,
 'user_id' => $array->users_id,
 ];

 if (CommentSpam::create($data)) {
 return true;
 }

 }
}
?>

Now we have all our required methods inCommentModel. So now let's clean upCommentController which is currently bit complex and lengthy in code structure. As right nowCommentController look like this:

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\Comment;
use App\CommentVote;
use App\CommentSpam;
use App\User;
use Auth;

class CommentController extends Controller
{


 
 public function index($pageId)
 {
 $comments = Comment::where('page_id',$pageId)->get();

 $commentsData = [];




 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $replies = $this->replies($key->id);
 $photo = $user->first()->photo_url;
 $reply = 0;
 $vote = 0;
 $voteStatus = 0;
 $spam = 0;
 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();


 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }


 if(sizeof($replies) > 0){
 $reply = 1;
 }

 if(!$spam){
 array_push($commentsData,[
 "name" => $name,
 "photo_url" => (string)$photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "reply" => $reply,
 "votedByUser" =>$vote,
 "vote" =>$voteStatus,
 "spam" => $spam,
 "replies" => $replies,
 "date" => $key->created_at->toDateTimeString()
 ]);
 } 


 }
 $collection = collect($commentsData);
 return $collection->sortBy('votes');
 }

 protected function replies($commentId)
 {
 $comments = Comment::where('reply_id',$commentId)->get();
 $replies = [];



 foreach ($comments as $key) {
 $user = User::find($key->users_id);
 $name = $user->name;
 $photo = $user->first()->photo_url;

 $vote = 0;
 $voteStatus = 0;
 $spam = 0; 


 if(Auth::user()){
 $voteByUser = CommentVote::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();
 $spamComment = CommentSpam::where('comment_id',$key->id)->where('user_id',Auth::user()->id)->first();

 if($voteByUser){
 $vote = 1;
 $voteStatus = $voteByUser->vote;
 }

 if($spamComment){
 $spam = 1;
 }
 }
 if(!$spam){


 array_push($replies,[
 "name" => $name,
 "photo_url" => $photo,
 "commentid" => $key->id,
 "comment" => $key->comment,
 "votes" => $key->votes,
 "votedByUser" => $vote,
 "vote" => $voteStatus,
 "spam" => $spam,
 "date" => $key->created_at->toDateTimeString()
 ]);
 }




 }


 $collection = collect($replies);
 return $collection->sortBy('votes');
 }

 
 public function store(Request $request)
 {
 $this->validate($request, [
 'comment' => 'required',
 'reply_id' => 'filled',
 'page_id' => 'filled',
 'users_id' => 'required',
 ]);
 $comment = Comment::create($request->all());
 if($comment)
 return [ "status" => "true","commentId" => $comment->id ];
 }

 
 public function update(Request $request, $commentId,$type)
 {
 if($type == "vote"){


 $this->validate($request, [
 'vote' => 'required',
 'users_id' => 'required',
 ]);

 $comments = Comment::find($commentId);
 $data = [
 "comment_id" => $commentId,
 'vote' => $request->vote,
 'user_id' => $request->users_id,
 ];

 if($request->vote == "up"){
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote++;
 $comments->votes = $vote;
 $comments->save();
 }

 if($request->vote == "down"){
 $comment = $comments->first();
 $vote = $comment->votes;
 $vote--;
 $comments->votes = $vote;
 $comments->save();
 }

 if(CommentVote::create($data))
 return "true";
 }

 if($type == "spam"){


 $this->validate($request, [
 'users_id' => 'required',
 ]);

 $comments = Comment::find($commentId);


 $comment = $comments->first();
 $spam = $comment->spam;
 $spam++;
 $comments->spam = $spam;
 $comments->save();

 $data = [
 "comment_id" => $commentId,
 'user_id' => $request->users_id,
 ];

 if(CommentSpam::create($data))
 return "true";
 }
 }

 
 public function destroy($id)
 {
 }
}?>

After cleaning up the controller it will look much simpler and easy to understand like this:

<?php

namespace App\Http\Controllers;

use App\CommentModel;
use Illuminate\Http\Request;

class CommentController extends Controller
{

 private $commentModel = null;
 private function __construct()
 {
 $this->commentModel = new CommentModel();
 }

 
 public function index($pageId)
 {
 return $this->commentModel->getAllComments($pageId);
 }

 
 public function store(Request $request)
 {
 $this->validate($request, [
 'comment' => 'required',
 'reply_id' => 'filled',
 'page_id' => 'filled',
 'users_id' => 'required',
 ]);
 return $this->commentModel->createComment($request->all());
 }

 
 public function update(Request $request, $commentId, $type)
 {
 if ($type == "vote") {

 $this->validate($request, [
 'vote' => 'required',
 'users_id' => 'required',
 ]);

 return $this->commentModel->voteComment($commentId, $request->all());
 }

 if ($type == "spam") {

 $this->validate($request, [
 'users_id' => 'required',
 ]);

 return $this->commentModel->spamComment($commentId, $request->all());
 }
 }

}
?>

Wrap Up!

So Isn't it looking much cleaner and simpler to understand now? This is what actually a thin controller and fat model looks like. We have all our logic related to Comment system programmed in ourCommentModel and our controller is now just used to transfer data from the user to our model and returning the response which is coming from our model.

So this is how the structuring of the thin controller and fat model is made. Give your thoughts in the comments below.