My OS is Ubuntu (Natty atm), and apt makes it easy to install by just typing:

gmilby@mini64:~/Dropbox$ sudo apt-get install apache2-utils

1. Number of simulated connections – this simulates the number of visitors to your webapp, and if there are bugs and code errors, it will result to a very poor performance in actual deployment which can slowed down if there are a lot of users in your website.

2. Number of simulated concurrent users – these are the actual number of users that are using the application at exactly the same time. Of course in a very low traffic website, the concurrent users is almost zero because the probability that two users will exactly hit the application and do the same request is very small. This can be an issue with high traffic websites; it is because the number of concurrent users can slowed down the application and put a significant load on the web server. Some web host even limits the number of concurrent users (typically those that are originating from a free web hosting scheme).

Having the ability for the average developer to have access to such a tool as this enables them to be able to at least be aware of potential problems, and can give the developer enough time to research alternate coding methods. It can also shape the actual development. If you start using a huge framework, and realize how much bulk is being carried along to deploy a small app – it may be best to scale it down – look for a more practical approach. Knowing how your site will perform through every stage can save valuable time and embarrassment.

<code>ab -n [number of simulated connections] -c [number of simulated concurrent users] [url]

ab -n 3000 -c 3 http://mall.syrbot.com:81/ > main-mall-results.txt (it is not required, but i like to have a copy of my test results - to refer to)

</code>

This is ApacheBench, Version 2.3

Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/

Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking mall.syrbot.com (be patient)

Server Software: nginx/0.7.67

Server Hostname: mall.syrbot.com

Server Port: 81

Document Path: /

Document Length: 16447 bytes

Concurrency Level: 3

Time taken for tests: 160.446 seconds

Complete requests: 3000

Failed requests: 0

Write errors: 0

Total transferred: 49821000 bytes

HTML transferred: 49341000 bytes

Requests per second: 18.70 [#/sec] (mean)

Time per request: 160.446 [ms] (mean)

Time per request: 53.482 [ms] (mean, across all concurrent requests)

Transfer rate: 303.24 [Kbytes/sec] received

Connection Times (ms)

min mean[+/-sd] median max

Connect: 39 53 95.0 49 3051

Processing: 81 108 88.1 107 4670

Waiting: 41 53 10.5 53 335

Total: 125 160 129.9 157 4720

Percentage of the requests served within a certain time (ms)

50% 157

66% 162

75% 165

80% 167

90% 172

95% 177

98% 188

99% 207

100% 4720 (longest request)

These results show that the longest render of the website took 4720 milliseconds. Which is not bad considering it is the bottom of the line VPS, and pushing a ton of jQuery, Python and CSS for each page render (all 3000 requests!). the average was 157 milliseconds – so my choice to use NGINX to serve and Bjeorn pure C wsgi server turned out to be a good choice this time.

You can bet I will be using this from here on out. It helps me to know that new technologies may be reliable. It’s easier to trust a technology if you know the load it can stand.

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Add to this self-imposed regiment of learning, the process of absorbing something new – still in Beta, and the craziness factor goes up a few levels… While my chops are getting proofed, the developer is not even  finished – the plugin isn’t solidified and ready for release!

jQuery templates (tmpl()) is one of these type of endeavors.  The functionality is there, but nothing is set in stone yet. However, these are the basic concepts that are not published anywhere at the moment.

The basic premise is you get a piece of data, a json string.  In jQuery, a data string look like this: (notice the “[" & "]” on each end of the string)

[{"id":"1","title":"Home","content":"Home Page...\r\nLorem ipsum dolor sit amet, ","region":"main","display":"1"}]

Don’t let this get confusing off the bat. It is EXACTLY just like a row from a database table. Look closer at the first few pieces:

[{

"id":"1",

"title":"Home",

"content":"Home Page...

No surprises... it's just the column name, and the data that it has assigned to it.

When javascript (jQuery) passes a json string, it is wrapped in the braces ("[ ... ]"). The jQuery tmpl() method strips these off (for our convenience, or for functionality of jQuery - no one was able to give a definitive answer on that question), but when we work with this json string, it will be a pure piece of data thanks to the braces being stripped off.

This may seem like a tedious approach, but if you want to do more than just sling a string at your front end, then you'll want to know what it is you're controlling (the data).

For now our data looks like this:

data = var people = [
{
firstName: "John",
lastName: "Doe",
}
];

,  we're doing 'onesies' before going nuts and adding more data!

An easy way to think of this is, we have our data. We have a var named, "people", and it has one object (one key and one value).  If you output people.firstName, it will equal "John".  If we output people.lastName, it will equal "Doe".

When working on something 'new', it's good to use the latest CDN (content delivery network) version of the scripts. As it turns out, this is wise, considering tmpl is still BETA - it's nice to know if something "I KNOW" worked, stops working due to a change in the code plugin.

The next step is to make a function to extract the data we want to extract from the string.

function getFirstName() {
return this.data.firstName;
}

When 'getFirstName()' is executed, it will get look at the data we've predefined. You've probably guessed that we could get lastName with such a function too? (you're right!).  Regardless of how much data was defined in the structure, we could extract it this way.

$(function(){
$( "#tmplPeople" )
.tmpl( people )
.appendTo( ".peopleTable" );
});

Before tip the box over and let you look in, it may be best to explain what 'will be happening' when it all fires.

This function will look for a defined template called, "#tmplPeople". it will look at your predefined data (people - of which we have one entry for now). It will take the data, place it into the template (named tmplPeople) and then snap it into the peopleTable. S0,  our one data entry, will be formatted, then put into the html table.

<script id="tmplPeople" type="text/x-jquery-tmpl">
<tr>
<td colspan="2">${getFirstName()} </td>
</tr>
</script>

<table><tbody></tbody></table>

here is our <table>, that will house the templates after the data is parsed by the function we looked at above. Right above the <table> is our template we labled "tmplPeople". As you can see, each time that template is called (tmplPeople), it is going to call our 'getFirstName' function, and it is going to take the first name from our data, and populate it into the template, then it will add it to the table.

Here is the whole code snippet, if this generates any feedback, we'll continue onto the many other ways to parse data from json!

<script src="http://code.jquery.com/jquery-latest.min.js"></script>
 <script src="http://ajax.microsoft.com/ajax/jquery.templates/beta1/jquery.tmpl.min.js"></script>

<script type="text/javascript">// <![CDATA[

function getFirstName() {
return this.data.firstName;
}

function getLastName() {
return this.data.lastName;
}

$(function(){
$( "#tmplPeople" )
.tmpl( people )
.appendTo( ".peopleTable" );
});

// ]]></script>

<script id="tmplPeople" type="text/x-jquery-tmpl">// <![CDATA[

<tr>
<td colspan="2">${getFirstName()}  ${getFirstName()}</td>
</tr>

// ]]></script>
<table>
<tbody></tbody>
</table>

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These are the “mostly used” statements:

FROM (Table to retrieve data from)

WHERE (Row-level filtering) 

GROUP BY (Group specification)

HAVING (Group-level filtering)

ORDER BY (Output sort order)

If anyone is interested, i’ll post the rest of my notes here on SQL(?). The order varies some depending upon use. Another useful item of interest is that the SQL (“mostly-regardless” of the flavor [mysql, mongo, oracle/etc...]), is that they all speak ‘SQL’. That may sound redundant, but it is actually interesting to start discovering the approaches that are implemented that all basically ‘do the same thing’ or ‘place higher priorities on certain operations’.

Once you learn what each flavor of SQL is doing, what their design goal was, it’s interesting to learn you may be using something totally overkill for a simple purpose. In most cases for a small production website, SQL Lite may be perfectly acceptable for lower traffic/connection sites (which are the vast majority of all sites on the web). Some ‘family-type- websites have even been known to use flat-text files.

The downside to using a larger-scale SQL solution is that most people do not use it correctly in the first place. That’s fine to use it, but it’s kind of like driving a NASCAR to the supermarket.  Just because you “have and use” more power, doesn’t make it faster for the end client/customer. A basic website (3-10 pages), using Apache, NGINX, Lighttpd (webservers), along with basic HTML(preferably HTML5 + CSS3), and maybe jQuery (if you need some pzazz), is more than enough for the basic website.  It’s fast, secure, presentable, and allows the author to maintain their focus (do what they were trying to do in the first place [get their message onto the web]).

If your goal is to see how much horse power you can use – see how flashy and widgetized you can get, then you’re missing the point of web development on the internet.  It’s cool to use the latest thing, but it’s cooler to get your message understood. Even if your message is to sell something, save a puppy from being put down, or getting your beliefs/blogging your experiences. If your page loads quickly, is easy to read, is obvious what you expect the reader to ‘get from your web presence’, then you and your web page reader/browser will enjoy a good relationship.

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$.ajax()

http://jsbin.u1st.us <–use jsbin to share your code!

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Sites that will allow you to upload an avatar or an image – like blogs, forums, and media featured sites – often have a size restraint, and it leave some people not knowing how to get their favorite image uploaded to the site.

The basic premise is that the image has a weight, measured in megabytes – before this goes south and someone falls asleep, it’s basically just comprised of how many colors, how big, and how technical the image is.

because of the number of factors, it’s usually easier to just utilize an upload/resizing service that will do the job for you.  Some of these services will allow you to decide up front how big/how much file weight you want to have the image ‘shaved down to’.  Some just use verbiage like “small”, “smaller”, etc…

Some social network sites, will even scale the image down for you now – but even then, it has to be below a certain size.

Here are some of the more “user-friendly” online resizing tools that I’ve found:

• Resizr
• ResizeYourImage
• PicResize
• ResizeToMail
• ImageResizer
• ResizeIt
• ShrinkPictures

Like most services on the internet, these are free (for now). Also, most of these services will do one thing/feature that the other will not do.  ResizeToMail gives you the option to skew images down to specific scale size (width vs height), while another allows for zoom and crop (which are nice if you want to cut out a bad background)

Please reply with any experiences you have at any of these sites, and likewise, let us know if you have another site you could recommend.

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Follow the steps to deploy a website or web-application in Google App Engine:

1) Create a account in Google AppEngine:

a) Go to http://appengine.google.com and sign in (with a Google/Gmail account) to the service. When you sign in, you will create a project too. This project have a app-id ( a identifier, please anote it ).

2) Download the latest version of AppEngine SDK:

a) Go to  http://code.google.com/appengine/downloads.html and download the latest version of AppEngine SDK for Python for your Operation System.      b) Extract the compacted file in your home folder for example. This will create a folder called “google_appengine”. This folder contains all necessary files to develop, debug and deploy your app in GAE.

3) Download the skeleton app ‘webpy-gallery’ and alter the app.yaml file:

a) In the google_appengine folder get the webpy-gallery app. This app contains a basic skeleton of a web.py app to run in GAE.

svn checkout http://webpy-gallery.googlecode.com/svn/trunk/ webpy-gallery

Now in the google_appengine folder you have a sub-folder called webpy-gallery and in this sub-folder you have a file called app.yaml. This file is a deployment descriptor where you can configure ‘what’ and ‘how’ deploy in GAE. Then as a first step, alter the application property for the id of the application that you have created in STEP 1.

4) Run the application in dev mode:

a) To test your app, open a shell (bash) and go to google_appengine folder and type;      python dev_appserver.py webpy-gallery        This will start the ‘development webserver’ in the address http://localhost:8008 then you can access this address in the browser.

5) Deploy your application in GAE:

For deploy your app in GAE just run the command:

python appcfc.py update webpy-gallery

6) Last tip:

- Ever that you alterate a html file, you need compile this file before update your app, the go to the webpy-gallery folder and execute the shell script compile_template.sh

Special Thanks to Leandro of ProfessionalIT for his extensive research & sharing his quickstart for the GAE.

Need a “Break?”

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Here are some things to consider when you’re trying to enable a service, application or server in Ubuntu.  Bookmark this and pull it up the next time you need to make something work in Ubuntu, before you start hurling your pc across the room

Apparmor, may not be your friend… the average person who uses full-blown Ubuntu, also owns a firewall/router – Apparmor is ‘overkill’ in my humble opinion.  However, if you’re connected directly to your cable modem, it could be useful (see first sentence).

If YOU ARE behind a firewall/router, and you DO NOT need a software firewal solution, then use these commands to disable Apparmor. In most cases this will fix your connection issues:

AppArmor can be disabled, and the start-up module removed by entering the following:
sudo /etc/init.d/apparmor stop
sudo update-rc.d -f apparmor remove
To re-enable AppArmor enter:
sudo /etc/init.d/apparmor start
sudo update-rc.d apparmor defaults

UFW, is another term to be familiar with.  It’s the firewall app that is installed along side Apparmor. If you are trying to directly access ports, you can enable specific ports, or (again) totally disable to application if you know you are protected by a hardware router/firewall device (like a Linksys, Netgear DSL/Cable Router/Firewall)

Here are the common UFW control commands:

ufw needs to be enabled. From a terminal window enter:

sudo ufw enable
To open a port (this example is for ssh):
sudo ufw allow 22

Likewise, to close an opened port:
sudo ufw deny 22

To remove a rule, use delete followed by the rule:
sudo ufw delete deny 22

If the port you want to open or close is defined in /etc/services, you can use the port name instead of the number. In the above examples, replace 22 with ssh.


This quickstart will help you get your app’s online quick, and allow you to connect to them.

Please make any suggestions, and we will update the post. it’s good to see the Linux community coming together and giving M$ a run for their money

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One thing that always seems to leave potential crontab’ers confused is the syntax of the file.  Knowing how to setup the time function to capture the intended task seems to be the biggest obstacle.

Considerations that you may want to consider before setting up a job would be:

• Is the task going to have a high utilization?
• Will the task take a long period to run?
• How often does the task need to be executed?

If it is a task that is going to use a lot of system resource, then schedule it to run during off hours.  This seems like a no-brainer, but anyone who has worked in system administration can tell you a horror story about someone trying to run rsync backups during the day so they wouldn’t have to switch out tapes during the night – causing horrendous speed & processing drop-off  to everyone connected to the system.

In the same light, If it’s going to take forever to run (in excess of an hour), then schedule it for the overnight also. During times when people will not have need for system resources.

If you’re task qualifies as both, heavy use/long time to run, then schedule it for the weekend or over a holiday.

The charts this post demonstrate the same chart in a couple of different methods.  Being visual – my first choice is always a chart.

First off, to enter a crontab, type

~$crontab -e at the command prompt.

What these crontab columns mean are this:

example: 30 08 10 06 * /home/ramesh/full-backup

• 30 – 30th Minute
• 08 – 08 AM
• 10 – 10th Day
• 06 – 6th Month (June)
• * – Every day of the week

The variation of scheduling can be subtle, but here are a few examples:

To schedule a job twice a day:

00 11,16 * * * /home/ramesh/bin/incremental-backup

• 00 – 0th Minute (Top of the hour)
• 11,16 – 11 AM and 4 PM
• * – Every day
• * – Every month
• * – Every day of the week

An example crontab task may look something like:

MAILTO=cron@username.plus.com* * * * * /command/to/execute

Not to be thrown off, look at this cron job that will run every five minutes:

0,5,10,15,20,25,30,35,40,45,50,55 * * * * /command/to/execute

It’s common practice to have comma delimited lists in a column position to execute a command within units of the column it is in – especially in the minutes and hours column.

Hopefully this post will serve as a quick reference so that you can quickly setup a crontab without much trouble. Let me know (via comments) if you would like to explore any other aspect of this, and I will try to put something together.

Found this quick reference list, wanted to add it to the post – quick reference for the ‘usuals’:

string meaning
------ -------
@reboot Run once, at startup
@yearly Run once a year, "0 0 1 1 *"
@annually (same as @yearly)
@monthly Run once a month, "0 0 1 * *"
@weekly Run once a week, "0 0 * * 0"
@daily Run once a day, "0 0 * * *"
@midnight (same as @daily)
@hourly Run once an hour, "0 * * * *"


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Add This offers statistical data so you can track how many times your site  was referred using their tool, but you will have to sign up for an account to be able to use that feature… After all, they need to know who to give the tally to

The list of networking sites seems to be growing at an unbelievable rate, and it’s great that someone is keeping up with all the js/api links that can connect stories or web items to their ‘circle of friends’ or colleagues.

Another one that has caught my attention is , “Share This“.  Share this seems to have a few more dynamic elements – a smoother presentation, but the number of services it can ‘share to’ are probably equal to any other like-service. One thing that seperates Share This apart is the application method – you’re able to literally download the plugin within a ‘format’ (e.g. wordpress, typePad, or generic script for any regular coding website).

As mentioned earlier, there are a few user-centric web applications starting to come to the forefront. One of the most significant is Threadsy.  At first I wasn’t sold on the all-in-one web tool idea, but after using it for a month, it’s become an essential tool.  It’s so easy to twitter, and if it’s appropriate, I can simultaneously post to Facebook.  It keeps all my email in one place (my tens of throw away/ sole-purpose email addresses [that i would never check otherwise?]).  The irony is I like Threadsy for the very reasons that I thought I would ever like an application like this… It has a vertical bar (as small as I want it to be) that can show me my twitter account/facebook notices without getting an email… if something scrolls by & I happen to want to reply – it’s a matter of clicking a button after typing my response.  At any given time, I used to have up to 20 browser window/tabs open. With Threadsy, it’s reduced to 5.

Regardless which one of these mash-up tools you use, be sure to share your findings in the comments.  We appreciate the comments and participation.

Thanks,

Greg

If you liked this post, please follow me on Twitter

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Figure 1 The Problem Steps Recorder dramatically speeds up troubleshooting. (Click the image for a larger view)

The Credential Manager provides a handy, secure place to store passwords.

Windows 7 adds a great deal of virtualization support, including the ability to create and attach virtual hard drives from the GUI.

Don’t forget to enter the Antispyware Give-away for December 2009!
Two lucky winners have won a free professional license of Superantispyware!

If you liked this post, please follow me on Twitter

—–Ammendment—

I found a complete list of shortcuts for Win7 – 99 Windows 7 Shortcuts

this list was mined from http://www.7tutorials.com/biggest-library-windows-7-shortcuts  they seem to have several great no non-sense tutorials regarding windows 7

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