N Rao Lakkakula's Blog

How to Setup EC2 API Command line Tools on Windows PC

Bob Lakkakula — Wed, 10 Mar 2010 02:33:44 +0000

Download API Tools from http://developer.amazonwebservices.com/connect/entry.jspa?externalID=351&categoryID=88

Extract the zip file to C:\ folder (to avoid paths with quotes issues in windows). I also renamed the folder to “ec2-api-tools”

Set Java Home Environment Variable. Usually this looks like “C:\Program Files\Java\jrexxx”. Find out exact path on your computer

From Command Prompt

> cd C:\ec2-api-tools
> set JAVA_HOME=”C:\Program Files\Java\jre6″

Set EC2_HOME variable

> set EC2_HOME=C:\ec2-api-tools

Now Get Private key and Certificate Files and keep in C:\ec2-api-tools\keys\ folder for convenience.

Now you can test api-tools

> C:\ec2-api-tools\bin>ec2-describe-availability-zones -K C:\ec2-api-tools\keys\pk-xxx.pem -C C:\ec2-api-tools\keys\cert-xxx.pem

How to debug MySQL Connector Library in Visual Studio

Bob Lakkakula — Fri, 25 Dec 2009 21:48:37 +0000

In text:

1. Download “mysql-connector-net-6.2.2-src.zip” from http://dev.mysql.com/downloads/connector/net/ and extract the zip file. Note that we need ‘src’ version of library if we want to debug in visual studio.

2. Open your Visual Studio Solution and add ”Mysql.data.csproj” located at “MySql.Data\Provider\” inside the extracted archive.

3. Add this project’s reference to your project (mysql.data).

4. Now you can debug into mysql.data methods.

Tagged: Connector/.NET, Debugging, MySQL, Visual Studio

Quick How To: Record SQL Results to Text File in PostgreSQL

Bob Lakkakula — Thu, 03 Dec 2009 04:10:40 +0000

Once you connected using psql,

# \o /tmp/myrecord.txt

Then run any SQL queries you want. They wont be visible on screen But will be recored to /tmp/myrecord.txt

# SELECT * FROM my_super_dummy_table;

#\q

How To: Rails with SQL Server 2008

Bob Lakkakula — Sun, 01 Nov 2009 16:40:30 +0000

Most common database used with Rails is mySQL but if you ever need to use SQL Server, here is a quick how to.

I am using Windows Vista, SQL Server 2008, Rails 2.2.

1) Install activerecord-sqlserver-adapter gem

> gem install activerecord-sqlserver-adapter

2) Create a new Login for this new database (say testuser) using SQL Server Management Studio

3) Create a new database in SQL Server 2008 for your project (say testproject) and choose testuser as Owner

4) Create a new ODBC DNS

Control Panel -> Administrative Tools -> Data Sources (ODBC)

Add a new ‘User DSN’, choose SQL Server, give a name for DSN (say testprojectconn) then configure SQL Server authentication.

5) Now create your rails application as usual. Configure db connection using database.yml as follows

adapter: sqlserver
mode: odbc
dsn: testprojectconn
host: localhost
username: testuser
password: testpass
encoding: utf8

Thats it!

How to setup a Cisco VPN Client on CentOS 5.3

Bob Lakkakula — Mon, 26 Oct 2009 03:22:35 +0000

This blog post deals with VPNC (http://www.unix-ag.uni-kl.de/~massar/vpnc/) : an alternative to Cisco’s linux version client. If you happy with cisco’s client and were able to install it successfully then you can skip the rest of the blog.

Most of the information can be found at original sources http://wiki.centos.org/AdditionalResources/Repositories/RPMForge and http://wiki.centos.org/HowTos/vpnc

Only issue you might face is installing yum prorities using yum. That is broken in CentOS 5.3 (atleast til I tried). So here are the steps involved.

1) Install Yum Prorities

Install prorities using rpm instead of yum.

wget http://mirror.centos.org/centos-5/5.3/os/i386/CentOS/yum-priorities-1.1.16-13.el5.centos.noarch.rpm

rpm -ivh yum-priorities-1.1.16-13.el5.centos.noarch.rpm

2) Check if plugin is enabled (see http://wiki.centos.org/AdditionalResources/Repositories/RPMForge for details)

nano /etc/yum/pluginconf.d/priorities.conf

3) Update Proirities for repo files

nano /etc/yum.repos.d/CentOS-Base.repo

4) Install rpm forge

wget http://apt.sw.be/redhat/el5/en/x86_64/RPMS.dag/rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

rpm –import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt

rpm -K rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm
rpm -i rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

5) Update prority for rpmforge repo file

nano /etc/yum.repos.d/rpmforge.repo

6) Update yum to start using priorirites and rpmforge as source.

yum check-update

7) install VPNC

yum -y install vpnc

Now vpnc is installed. Follow http://wiki.centos.org/HowTos/vpnc to know how to use it.

Tagged: CentOS, Linux, VPN

How to Quickly Visualize/Analyze a MySQL Database?

Bob Lakkakula — Mon, 26 Oct 2009 02:54:44 +0000

Once in a while we been in situations where you need to quickly understand/analyze a database given to you by others. We can go through each table and try to understand but it is usually lot simpler if you can visualize all the tables involved and relationships between those. Enter SchemaSpy: a free tool to do that. For sake of specifics, say the database given is MySQL and your pc is running some version of Windows.

A. Download and Install Pre-requsites (if you dont have already)

Graphviz (http://www.graphviz.org/Download_windows.php)
- use MSI installer (see warnings specific to vista on the download page)
Java (http://www.java.com/en/download/index.jsp)
- Download and install Java as usual.
JDBC driver for mySQL ( http://dev.mysql.com/downloads/connector/j/5.1.html)
- Download driver and extract to a known location (say C:\mydblayout)

B. Download latest SchemaSpy Jar File from http://sourceforge.net/projects/schemaspy/files/ (In my case it is schemaSpy_4.1.1.jar) to a known location (using same C:\mydblayout)

Now run the schemaspy to generate report (html format) for database ”mytestdb” which is sitting at a local mySQL server.

C:\mydblayout>java -jar schemaSpy_4.1.1.jar -t mysql

-dp mysql-connector-java-5.1.10\mysql-connector-java-5.1.10\mysql-connector-java-5.1.10-bin.jar

-db mysql -host localhost -u root -p mysecretpass -o mytestdb_report

See how -dp flag is used to point to jdbc driver. The above command creates a folder called “mytestdb_report” with all the nice html files. Just open the “index.html” file.

For example output see http://schemaspy.sourceforge.net/unifieddb/characters/index.html

For more details, look at web page of this wonderful SchemaSpy (http://schemaspy.sourceforge.net/) written by John Currier.

Tagged: MySQL, Schema, Visualize Schema

Having trouble debugging VS 2003/2005 Projects after upgrading to IE 8 ?

Bob Lakkakula — Fri, 11 Sep 2009 14:38:38 +0000

Close all IE8 windows…

if you have any IE window open, then VS cant start debugger….

Its not a problem with VS2008

Close all IE8 windows…

if you have any IE window open, then VS cant start debugger….

Its not a problem with VS2008 onwards.

Security Hole in IPhone with AT&T

Bob Lakkakula — Sat, 05 Sep 2009 14:53:14 +0000

To be more precise, the security hole is with the network (AT&T network) IPhone uses. I noticed this problem while working on a Voice-enabled application using Asterisk and surprised to see that my voicemail is wideopen to public. Then later found out that this has been reported earlier by various folks (here and here) but seems like it is not fixed yet. So if you own an IPhone (or any other phone for that matter) with AT&T network, please keep reading and I show you how to fix the problem yourself.

So what is the problem?

Others can listen to your voice mail, change your personal greeting and other settings. AT&T voicemail identifies user based on incoming caller ID, so if callerID matches the phone # you are calling from, it assumes that you are calling yourself to check voice mail then it simply goes to voice mail (if you don’t have password set).

Am I protected or Not?

Call yourself with your phone (by dialing 1 or dialing your number). If you are prompted for a password, then you are fine. If it takes your directly to voice mail menu, then you are NOT secured. See how to set password below.

How to protect my voice mail?

Dial 1 to call Voicemail from your phone

Press * to get to the voicemail Main Menu

Press 4 for Personal Options
Press 2 for Administrative Options
Press 1 for Passwords
Press 2 to turn password on
Select any random 4– to 14–digit password

Why I am blogging this?

I don’t know if new AT&T users may be forced to set password or not, but when I got my phone couple of years back and my voicemail was setup without password. It ended up that most of my friends with IPhone also don’t have password setup for voicemail because simply they are not aware of the security hole. With easy access to Open source PBX like Asterisk or spoofing calling cards, its not hard to exploit this security hole. So if this blog helps people to realize how important is to set password, then my job is done.

Disclaimer

The opinions expressed in this blog post are my own and not of any company. The usual standard disclaimer applies, especially the fact that I am not liable for any damages caused by direct or indirect use of the information. I bear NO responsibility for content or misuse of this information or any derivatives thereof. This post is NO WAY intended to blame anyone, especially AT&T. They may have already posted about this issue somewhere on their website.

Tagged: Asterisk, Iphone, Security, Voice mail

Nice and easy tool tip

Bob Lakkakula — Thu, 16 Jul 2009 18:02:58 +0000

I found this snippet of code from somewhere on internet which is simple yet elegant. Idea here is pretty simple: hide tooltip originally using CSS display property and show it when mouse hover over it.

Usage :

link text goes here tool tip text goes here….

CSS needed:

Interesting comments found on other technical blogs

Bob Lakkakula — Sun, 22 Feb 2009 18:08:15 +0000

“If it is fast and ugly, they will use it and curse you; if it is slow, they will not use it.”- David Cheriton, The Art of Computer Systems Performance Analysis (From http://www.kriskrause.com/2009/04/mysql-connector-net-mysqlbulkloader.html)

Weighing cost versus reliability is always a difficult choice in systems administration. (From http://www.linuxhomenetworking.com/wiki/index.php)

I have noticed that people who hate George Bush also hate internet explorer and Windows in general. You people are mentally ill, sorry to say. (From http://sql-info.de/en/mysql/gotchas.html#1_5 )