Dev on chaosplay

Backup VPS

Sun, 10 Sep 2023 11:38:32 -0500

Here are simple steps to backup your VPS.

Backup MySQL database

Create a directory to store the backup files. Then run mysqldump command to backup your database.

mysqldump -u your_mysql_user -pyour_mysql_password your_database_name > /path/to/dump_$(date +\%Y\%m\%d\%H\%M\%S).sql

Or you run it as superuser and backup all databases at once.

sudo mysqldump --all-databases > /path/to/dump_$(date +\%Y\%m\%d\%H\%M\%S).sql

To automate this, schedule a cron job that will run this command on a daily basis.

crontab -e

Insert the following line to execute the mysqldump command every day at midnight.

A quick script to build and deploy hugo site on VPS

Wed, 06 Sep 2023 14:06:31 -0500

I had been using GitHub and Netlify for this site but lack of some features such as access to server logs finally got too much. So I decided to move this blog to my VPS.

One thing I really love about using Github is CI/CD and Github Actions. But I wanted something even simpler with less dependencies. So I decided to use a simple bash script to build and deploy the site.

undefined method xxxxx' for #< Hash:0x00000 >

Wed, 14 Jun 2023 15:54:46 +0000

This error in our Rails application drove me crazy. The error was like this:

undefined method xxxxxx' for #<Hash:0x000000001234>

The problem was that I was calling a method like this: a_method(var: var)

And the method definition was like def a_method(var: var) which resulted in something called variable shadowing and caused clash between variable passed in the method and local variable being defined.

The fix was to change method definition to def a_method(var:)

Script inherits from native type 'RigidBody2D', so it can't be assigned to an object of type: 'Node2D'

Fri, 28 Apr 2023 21:47:32 +0000

Getting this error while following this tutorial in Godot v4.0.1.

In my case, I had added Node2D. The fix was to right-click on the problem node under Scene and click Make Scene Root. And then delete Node2D.

Here is what diff looked like:

diff --git a/2d-game-tutorial/Mob.tscn b/2d-game-tutorial/Mob.tscn
index 9eb1630..e720d7f 100644
--- a/2d-game-tutorial/Mob.tscn
+++ b/2d-game-tutorial/Mob.tscn
@@ -48,20 +48,18 @@ animations = {
 radius = 36.0
 height = 100.0

-node name="Mob" type="Node2D"]
-script = ExtResource("1_73gb4")
-
-node name="RigidBody2D" type="RigidBody2D" parent="."]
+node name="RigidBody2D" type="RigidBody2D"]
 collision_mask = 0
 gravity_scale = 2.66454e-15
+script = ExtResource("1_73gb4")

-node name="AnimatedSprite2D" type="AnimatedSprite2D" parent="RigidBody2D"]
+node name="AnimatedSprite2D" type="AnimatedSprite2D" parent="."]
 scale = Vector2(0.75, 0.75)
 sprite_frames = SubResource("SpriteFrames_c1yjy")
 animation = &"walk"

-node name="CollisionShape2D" type="CollisionShape2D" parent="RigidBody2D"]
+node name="CollisionShape2D" type="CollisionShape2D" parent="."]
 rotation = 1.5708
 shape = SubResource("CapsuleShape2D_h1pjc")

-node name="VisibleOnScreenNotifier2D" type="VisibleOnScreenNotifier2D" parent="RigidBody2D"]
+node name="VisibleOnScreenNotifier2D" type="VisibleOnScreenNotifier2D" parent="."]

How to backup Kubernetes' Config

Thu, 20 Jan 2022 20:45:36 +0000

The easiest solution seems to be the following script by Stack Overflow user, Timothy Perez

  <pre style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4"><code class="language-bash" data-lang="bash">#!/bin/bash

# NAMESPACED EXPORTS
 for  ns in  $( kubectl get ns --no-headers | cut -d " "  -f1 ) ;  do
  kubectl --namespace = " ${ ns} "  get -o = json bindings,cm,ep,ev,limits,pvc,po,podtemplates,rc,quota,secrets,sa,svc,controllerrevisions,ds,deploy,rs,sts,localsubjectaccessreviews,hpa,cj,jobs,leases,ev,ds,deploy,ing,netpol,rs,pods,netpol,pdb,roles,rolebindings |  \
       jq '.items[] |
     select(.type!="kubernetes.io/service-account-token") |
     del(
         .spec.clusterIP,
         .metadata.uid,
         .metadata.selfLink,
         .metadata.resourceVersion,
         .metadata.creationTimestamp,
         .metadata.generation,
         .status,
         .spec.template.spec.securityContext,
         .spec.template.spec.dnsPolicy,
         .spec.template.spec.terminationGracePeriodSeconds,
         .spec.template.spec.restartPolicy
     )'  >> "./ ${ ns} .json"
 done

# NON-NAMESPACED EXPORTS
kubectl get -o = json cs,ns,no,pv,mutatingwebhookconfigurations,validatingwebhookconfigurations,crds,apiservices,tokenreviews,selfsubjectaccessreviews,selfsubjectrulesreviews,subjectaccessreviews,csr,psp,nodes,psp,clusterrolebindings,clusterroles,pc,sc,volumeattachments |  \
       jq '.items[] |
     select(.type!="kubernetes.io/service-account-token") |
     del(
         .spec.clusterIP,
         .metadata.uid,
         .metadata.selfLink,
         .metadata.resourceVersion,
         .metadata.creationTimestamp,
         .metadata.generation,
         .status,
         .spec.template.spec.securityContext,
         .spec.template.spec.dnsPolicy,
         .spec.template.spec.terminationGracePeriodSeconds,
         .spec.template.spec.restartPolicy
     )'  >> "./cluster_non-namespaced_export.json"

Script copied here under CC BY-SA 4.0 license

Kubernetes not passing full path to Nodejs

Wed, 29 Dec 2021 21:23:42 +0000

I spent hours troubleshooting why the url path was getting stripped from requests in our Nodejs/Expressjs based app. The reason was this line in Kubernetes’ Ingress:

nginx.ingress.kubernetes.io/rewrite-target : /

Removing it fixed the issue. Check the Kubernetes documentation

for more details.

Ask HN: Software Engineer hitting 40: what's next?

Wed, 01 Dec 2021 17:46:18 +0000

Recent thread on Hacker News, https://news.ycombinator.com/item?id=29360119, was very interesting for me especially since I turned 40 this year.

Programming is something I enjoy and am pretty good at it. I’m still not at the top of the salary range for programmers but this is a tough question. I can get into FAANG but there is still a ceiling of how much one can earn as a software engineer.

This comment

says it best:

Wealth Lab Pro Earning Play Screener

Wed, 29 Sep 2021 16:12:14 +0000

This is a quick script that I use to find options to buy or sell.

 using  System;
 using  System.Collections.Generic;
 using  System.Text;
 using  System.Drawing;
 using  WealthLab;
 using  WealthLab.Indicators;
 using  Community.Components;

 namespace  WealthLab.Strategies
{
	 public class  MyStrategy  : WealthScript
	{

		 protected override void  Execute()
		{
			DataSeries maFast = EMAModern.Series(Close,  50 );
			DataSeries maSlow = EMAModern.Series(Close,  200 );
			DataSeries maFast_1 = EMAModern.Series(Close,  10 );
			DataSeries maSlow_2 = EMAModern.Series(Close,  50 );
			DataSeries ma = EMAModern.Series(Close,  10 );
			DataSeries maFast_3 = EMAModern.Series(Close,  10 );
			DataSeries maSlow_4 = EMAModern.Series(Close,  50 );

			PlotSeries(PricePane,EMAModern.Series(Close, 50 ),Color.Red,LineStyle.Solid, 2 );
			PlotSeries(PricePane,EMAModern.Series(Close, 200 ),Color.Green,LineStyle.Solid, 2 );
			PlotSeries(PricePane,EMAModern.Series(Close, 10 ),Color.Blue,LineStyle.Solid, 2 );
			PlotSeries(PricePane,EMAModern.Series(Close, 50 ),Color.Red,LineStyle.Solid, 2 );
			PlotSeries(PricePane,EMAModern.Series(Close, 10 ),Color.Blue,LineStyle.Solid, 2 );

			//for(int bar = GetTradingLoopStartBar(201); bar < Bars.Count; bar++)
 			 int  bar = Bars.Count -  1 ;
			{
				 if  (IsLastPositionActive)
				{
					Position p = LastPosition;
					 if  (p.EntrySignal.Contains("Group1|" ))
					{
						 if  (CrossUnder(bar, maFast_3, maSlow_4))
						{
							SellAtMarket(bar +  1 , p, "Group1" );
						}
					}

				}
				 else
				{
					 if  (maFast[bar] > maSlow[bar])
					{
						 if  (maFast_1[bar] > maSlow_2[bar])
						{
							 if  (Close[bar] < ma[bar])
							{
								 if  (EarningsDate.InWindow( this , bar, "earnings per share" ,  7 ,  0 ))
								{

									BuyAtMarket(bar +  1 , "Group1|" );
								}
							}
						}
					}

				}
			}
		}
	}
}

Docker in 5 minutes

Mon, 17 May 2021 16:09:00 +0000

I have been using Docker and Kubernetes for several years now but never really took any time to really read about it. There were a lot of gaps in my understanding of how Docker works and what really is possible with it. Just recently my employer started to offer a Udemy subscription, so I took the Hands on Docker course. Here are some of the important things I learned in this course.

Json_error_ctrl_char

Mon, 10 May 2021 11:12:00 +0000

I was using mcrypt to encrypt json_encoded data.

On the other side, mcrypt was able to decrypt data but json_decode was not working. It would throw JSON\_ERROR\_CTRL_CHAR error.

However, without mcrypt, json_decode worked flawlessly.

After some trial and error, I found that applying trim function after decrypting data would let me use json_decode without any issues.

Error Xcode Select Error Tool Xcodebuild Requires Xcode Active Developer Directory Command Line Tools Instance

Sun, 09 May 2021 21:17:00 +0000

Playing with Cordova, I was getting this error when building iOS version:

Error: xcode-select: error: tool 'xcodebuild' requires Xcode,
but active developer directory is a command line tools instance

Even full install of Xcode didn’t fix this error.

The solution was to run the following command to use full Xcode instead of command line tools version that I had installed earlier:

sudo xcode-select --switch /Applications/Xcode-beta.app/Contents/Developer

Setup Outgoing Email on Lightsail Ubuntu VPS

Sun, 09 May 2021 21:10:00 +0000

I followed instructions here: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-postfix-as-a-send-only-smtp-server-on-ubuntu-18-04

Everything seemed okay but emails were not getting delivered. Logs showed me that smtp connections were timing out:

tail -f /var/log/mail.log
May  3 12:28:10 postfix/smtp[3160]: connect to gmail-smtp-in.l.google.com[172.217.197.27]:25: Connection timed out
May  3 12:28:10  postfix/smtp[3160]: connect to alt1.gmail-smtp-in.l.google.com[2800:3f0:4003:c00::1a]:25: Network is unreachable
May  3 12:28:40 postfix/smtp[3160]: 4984C41A1E: to=<xxxx@gmail.com>, relay=none, delay=3246, delays=3186/0.01/60/0, dsn=4.4.1, status=deferred (connect to alt2.gmail-smtp-in.l.google.com[2a00:1450:400b:c00::1a]:25: Network is unreachable)

However, I could ping any of the above ip addresses just fine.

hsts Neterr_cert_common_name_invalid

Sat, 08 May 2021 21:14:00 +0000

Without full understanding, I had enabled HSTS on amerkhalid.com with option includeSubDomains. I had a subdomain that was used as “Custom Domain” to SmugMug site. After enabling HSTS, these subdomains started to throw NET::ERR_CERT_COMMON_NAME_INVALID.

The fix is of course simple, don’t use includeSubDomains. But that opens up your top level domain to man in the middle attacks.

For now, I decided to follow the best practices and leave includeSubDomains enabled. And decided to not use a custom domain for my SmugMug site.

TypeError: require.extensions.hasOwnProperty is not a function

Sat, 08 May 2021 21:07:00 +0000

While playing with https://github.com/alexa/interactive-adventure-game-tool, I ran into the following error:

> interactive-adventure-game-tool@1.0.0 start /Users/amer/alexa/interactive-adventure-game-tool
> node node_modules/gulp/bin/gulp.js

/Users/amer/alexa/interactive-adventure-game-tool/node_modules/require-dir/index.js:97
            if (!require.extensions.hasOwnProperty(ext)) {
                                    ^

TypeError: require.extensions.hasOwnProperty is not a function
    at requireDir (/Users/amer/alexa/interactive-adventure-game-tool/node_modules/require-dir/index.js:97:37)
    at Object.<anonymous> (/Users/amer/alexa/interactive-adventure-game-tool/gulpfile.js:1:85)
    at Module._compile (module.js:660:30)
    at Object.Module._extensions..js (module.js:671:10)
    at Module.load (module.js:573:32)
    at tryModuleLoad (module.js:513:12)
    at Function.Module._load (module.js:505:3)
    at Module.require (module.js:604:17)
    at require (internal/module.js:11:18)
    at Liftoff.handleArguments (/Users/amer/alexa/interactive-adventure-game-tool/node_modules/gulp/bin/gulp.js:116:3)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! interactive-adventure-game-tool@1.0.0 start: `node node_modules/gulp/bin/gulp.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the interactive-adventure-game-tool@1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/amer/.npm/_logs/2018-01-02T05_12_24_832Z-debug.log

The solution was to update require-dir to version 0.3.2 in package.json and run npm install again.

Troubleshooting Kubernetes Ingress

Tue, 04 May 2021 18:58:09 +0000

Setting up Ingress is an easy process but when it doesn’t work it gets really painful. First, make sure you have Ingress Controller setup correctly. This is in addition to Ingress resource and should be automatically setup by your cloud provider. When I was trying to setup a Kubernetes cluster on IBM Cloud, I ran into a lot of issues. It seems due to my permissions level something went wrong during provisioning of Kubernetes and Ingress Controller was not setup correctly. I went through a lot of steps including recreating alb , ingress resources, etc. The final fix was to login to IBM Cloud as superuser to change Access Policies for the cluster. Once I did that, everything just worked magically.

iPad Pro as main machine after 2 years

Fri, 26 Jun 2020 16:24:00 +0000

I got my iPad Pro at the end of 2017. Before buying it, I had read many blog posts by various developers who were using iPad for programming and web development. But soon after I bought it, I realized that serious web development on iPad is hard. The biggest issue was debugging JavaScript and CSS without web tools. At first, I was having buyer’s remorse but I loved the form factor of iPad and loved drawing on it. I am used to reading on Kindle and iPad was just too heavy for long reading sessions but it was a very decent reading device for quick reading sessions. So I kept it.

Git Simplified

Sat, 25 May 2019 13:44:01 +0000

One of the most common technologies that new professional developers struggle with is git.

Many junior developers are eager to start using all of the powerful commands of git and usually end up getting more confused.

Here are a few commands that I recommend to anyone learning git for the first time:

clone

This downloads the entire git repo from a remote server, usually. You will get all revision history and branches.

Tools of Trade

Mon, 25 Mar 2019 14:20:18 +0000

I use 13-inch MacBook Pro for personal projects and 15-inch for work. My personal MBP would be the last traditional laptop, hopefully. Since most of my work can easily be done on Linux VPS. I have been using a 10.5-inch iPad Pro with Blink shell for most of my side projects. I like the form factor of iPad Pro and I am getting better at Linux administration. Now I am also setting up Docker images so I can bring up new images as needed.

You don't need a web developer

Mon, 04 Dec 2017 01:08:41 +0000

Occasionally, when people find out I am a programmer, they ask me if I will build them a website or an app on the side. As I spend all day programming at my work, I rarely have the motivation to continue programming after work.

However, talking to most people, I realize they don’t need a programmer; most of their needs can be met by a simple SaaS solution. Recently, I directed a few friends to WordPress.com, SmugMug, Shopify, etc. They all were happy with the results and ease of use. Also I am glad they talked to me because one guy was ready to spend a few thousands on a developer for a WordPress-based site.

WordPress vs Hugo

Sat, 02 Dec 2017 13:44:01 +0000

Managing WordPress can get time consuming. I have tried to move to static website several times but kept going back to WordPress. But there are several advantages of static site generators, so I finally moved for good. I am also advising a lot of my clients to use Hugo especially when they know that they will rarely ever update their sites.

Here are some of the main advantages of Hugo (or other static site generators) vs WordPress and other CMS.

iPad Pro for Programming & Fun

Tue, 14 Nov 2017 17:10:00 +0000

I finally bought a 10.5" iPad Pro (Affiliate Link). It was mostly an impulse purchase. When I first started to use iPad, it felt blah. It is hard to find good apps or what apps you might want to try out.

My main goal with iPad was to have a really small laptop replacement. So I was hoping for a decent code editor. There are some code editing apps but there is no way to try them out before purchasing. So I am spending a lot of time reading reviews before I purchase any app.

ReflectionException: Class Tests\Unit\Symfony\Component\HttpKernel\Exception\NotFoundHttpException does not exist

Fri, 13 Oct 2017 23:12:25 +0000

Running unit tests in Laravel, I was getting this error:

ReflectionException: Class Tests\Unit\Symfony\Component\HttpKernel\Exception\NotFoundHttpException does not exist

The issue was a missing root backslash, make sure you have expected exception like:

$this->expectException(\Symfony\Component\HttpKernel\Exception\NotFoundHttpException::class);

Upgrading to PHP 7.0 on Ubuntu 14

Fri, 22 Sep 2017 21:22:20 +0000

I upgraded PHP to version 7.0 on an Ubuntu box. Running php -v on shell would show it as version 7.0. But Apache was still using PHP 5.6. I tried various methods to update settings for Apache but nothing worked until I issued the following commands:

sudo a2dismod php5.6
sudo a2enmod php7.0
sudo service apache2 restart

Source: PHP 7.0 (and 5.6) on Ubuntu | LornaJane

Setting Up Laravel on MacOS

Sat, 19 Aug 2017 15:58:05 +0000

After 3 years, I am using Laravel again at work. Laravel has extensive documentation but sometimes it can be a bit verbose. Here are commands to get you started as soon as possible. This assumes pretty much a fresh install of MacOS.

Install Homebrew

Check the official site for the latest command

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Install PHP 7.1

brew install homebrew/php/php7

Install MariaDB

brew install mariadb

Set MariaDB to start as a service at the end of installation.

Magento – Get All Products with Categories in a Flat View

Wed, 01 May 2013 20:11:53 +0000

     SELECT
        w1.website_id,
        w1.name  as  website_name,
        s1.store_id,
        s1.name  as  store_name,
        p1.entity_id  as  product_id,
        p1.sku,
        pname.value  as  product_name,
        url.value  as  url_path,
        small_image.value  as  small_image,
        msrp.value  as  msrp_price,
        price.value  as  price,
        p1.created_at  as  product_created_at,
        p1.updated_at  as  product_updated_at,
        visibility.value  as  visibility,
        pstatus.value  as  status,
         case
             when
                (pstatus.value  =   1
                     and  visibility.value  >   1 )
             then
                 1
             else   0
         end as  enable_flag,
        c1.entity_id  as  category_id,
        cname.value  as  category_name,
        c1.parent_id,
        c1.created_at  as  category_created_at,
        c1.updated_at  as  category_updated_at
     FROM
        catalog_product_entity p1
             inner join
        eav_attribute p_attr  ON  p1.entity_type_id  =  p_attr.entity_type_id
             and  p_attr.attribute_code  =  'name'
             inner join
        catalog_product_entity_varchar pname  ON  pname.entity_id  =  p1.entity_id
             and  pname.attribute_id  =  p_attr.attribute_id
             inner join
        eav_attribute p_attr2  ON  p1.entity_type_id  =  p_attr2.entity_type_id
             and  p_attr2.attribute_code  =  'url_path'
             inner join
        catalog_product_entity_varchar url  ON  url.entity_id  =  p1.entity_id
             and  url.attribute_id  =  p_attr2.attribute_id
             and  pname.store_id  =  url.store_id
             inner join
        eav_attribute p_attr3  ON  p1.entity_type_id  =  p_attr3.entity_type_id
             and  p_attr3.attribute_code  =  'small_image'
             inner join
        catalog_product_entity_varchar small_image  ON  small_image.entity_id  =  p1.entity_id
             and  small_image.attribute_id  =  p_attr3.attribute_id
             and  pname.store_id  =  small_image.store_id
             inner join
        eav_attribute p_attr4  ON  p1.entity_type_id  =  p_attr4.entity_type_id
             and  p_attr4.attribute_code  =  'msrp'
             inner join
        catalog_product_entity_decimal msrp  ON  msrp.entity_id  =  p1.entity_id
             and  msrp.attribute_id  =  p_attr4.attribute_id
             and  pname.store_id  =  msrp.store_id
             inner join
        eav_attribute p_attr5  ON  p1.entity_type_id  =  p_attr5.entity_type_id
             and  p_attr5.attribute_code  =  'price'
             inner join
        catalog_product_entity_decimal price  ON  price.entity_id  =  p1.entity_id
             and  price.attribute_id  =  p_attr5.attribute_id
             and  pname.store_id  =  price.store_id
             inner join
        eav_attribute p_attr6  ON  p1.entity_type_id  =  p_attr6.entity_type_id
             and  p_attr6.attribute_code  =  'visibility'
             inner join
        catalog_product_entity_int visibility  ON  visibility.entity_id  =  p1.entity_id
             and  visibility.attribute_id  =  p_attr6.attribute_id
             and  pname.store_id  =  visibility.store_id
             inner join
        eav_attribute p_attr7  ON  p1.entity_type_id  =  p_attr7.entity_type_id
             and  p_attr7.attribute_code  =  'status'
             inner join
        catalog_product_entity_int pstatus  ON  pstatus.entity_id  =  p1.entity_id
             and  pstatus.attribute_id  =  p_attr7.attribute_id
             and  pname.store_id  =  pstatus.store_id
             inner join
        catalog_category_product ccp  ON  ccp.product_id  =  p1.entity_id
             inner join
        catalog_category_entity c1  ON  c1.entity_id  =  ccp.category_id
             inner join
        eav_attribute c_attr  ON  c1.entity_type_id  =  c_attr.entity_type_id
             and  c_attr.attribute_code  =  'name'
             inner join
        catalog_category_entity_varchar cname  ON  cname.entity_id  =  c1.entity_id
             and  cname.attribute_id  =  c_attr.attribute_id
             and  pname.store_id  =  cname.store_id
             inner join
        catalog_category_product_index store1  ON  store1.product_id  =  p1.entity_id
             and  store1.category_id  =  c1.entity_id
             inner join
        core_store s1  ON  store1.store_id  =  s1.store_id
             inner join
        core_website w1  ON  s1.website_id  =  w1.website_id

OpenShift Error: Layer 7 Wrong Status, Invalid Response

Sun, 21 Apr 2013 20:11:02 +0000

I have been playing with OpenShift for the past several hours. It looks great. But a while back I started to get 503 Internal Server Error.

When I checked logs using rhc tail , I saw this error: Layer 7 Wrong Status, Invalid Response 404.

I spent an hour or so troubleshooting. Turns out the issue was NetBeans had added src/main/web/app/WEB-INF/jboss-web.xml when I ran the application locally on my machine. I committed this file, thinking I might need it. Deleting it from the repo fixed the issue.

How to Tell if a Number Is Whole in Php

Sat, 07 Jul 2012 16:05:03 +0000

if ($num == (int) $num) {
    // It's whole
} else {
    // It's not
}

Filter Some Keys in Multi Dimensional Arrays in Php

Sun, 22 Apr 2012 16:08:09 +0000

/**
 * Cleans up multi-dimensional arrays.
 * 1st dimension is a simple index
 * 2nd dimension includes the desired keys
 *
 * @param mixed $array
 * @param mixed $keysToInclude
 */
public function cleanUpArray($array, $keysToInclude) {
    $returnArray = array();
    $i = 0;

    foreach($array as $item){
        foreach($keysToInclude as $key){
            $returnArray[$i][$key] = $item[$key];
        }

        $i++;
    }

    return $returnArray;
}

MySQL Update If Exist Else Insert Procedure

Fri, 22 Apr 2011 00:54:43 +0000

Are you tired of checking data in your code before inserting? Well MySQL procedures are here to the rescue. This simple procedure shows how you can do that:

CREATE PROCEDURE   ` update_insert_user ` (  IN  uid2 int  )
 BEGIN
 DECLARE  last_login2 DATETIME;
 SELECT   ` last_login ` INTO  last_login2  FROM   `  user  ` WHERE   ` uid `   =  uid2  LIMIT   1 ;
 IF  last_login2  IS NULL THEN
 INSERT INTO   `  user  `  ( ` uid ` , ` last_login ` )  values  (uid2, now());
 ELSE
 UPDATE   `  user  ` SET   ` last_login `   =  now()  WHERE   ` uid `   =  uid2  LIMIT   1 ;
 END IF ;
 END

Codeigniter Creates a New Session With Each Page Load

Tue, 07 Sep 2010 16:15:32 +0000

Just spent 3 hours debugging a session bug in my webapp. CodeIgniter was creating a brand new session with each page load. The issue was a misconfiguration with my config file.

Fix was simple, in /application/config/config.php, make sure the correct domain is set for $config['cookie_domain'].

Codeigniter Out of Memory Error

Sat, 07 Aug 2010 16:12:32 +0000

Query Saving is a feature of CI’s database class that stores the results of every query in memory until the controller is finished executing. As it turns out, in version 1.6.0, the ability to turn this off was added. The addition of the save_queries variable is listed in the Change Log, but as of the latest release of 2.0.0 last week, it still hasn’t made the documentation.

$this->db->save_queries = FALSE;

via Undocumented CodeIgniter | Green Egg Media.

ssh_exchange_identification: Connection closed by remote host

Fri, 02 Jul 2010 01:05:55 +0000

I tried to login to my server tonight but kept getting the following error message:

ssh_exchange_identification: Connection closed by remote host

The fix was simple, at least if you have access to the server via cPanel. Just restart sshd service via cPanel/WHM.

Useful Sar Sysstat Examples for Unix Linux Performance Monitoring

Tue, 07 Jul 2009 16:20:10 +0000

Using sar, you can also collect all performance data on an on-going basis, store them, and do historical analysis to identify bottlenecks.

via 10 Useful Sar (Sysstat) Examples for UNIX / Linux Performance Monitoring.