Thursday, March 27, 2014

Installing R on Mac OS X

1) Install Homebrew in your system.

2) Download and install XQuartz (Homebrew does not package XQuartz and it is needed for step 3. Therefore install XQuartz.)

3) Install Fortran and R.
heshans@15mbp-08077:/tmp$ brew update

heshans@15mbp-08077:/tmp$ brew tap homebrew/science

heshans@15mbp-08077:/tmp$ brew install gfortran r 

4) Verify the installation by running R.
heshans@15mbp-08077:/tmp$ R

R version 3.0.3 (2014-03-06) -- "Warm Puppy"
Copyright (C) 2014 The R Foundation for Statistical Computing
Platform: x86_64-apple-darwin13.1.0 (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

  Natural language support but running in an English locale

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

Tuesday, March 25, 2014

Custom Log Formatter

Following is the source for a custom log formatter.

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.LogRecord;

public class CustomFormatter extends Formatter {

    private static final DateFormat df = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss.SSS");

    public String format(LogRecord record) {
        StringBuilder builder = new StringBuilder(1000);
        builder.append(df.format(new Date(record.getMillis()))).append(" - ");
        builder.append("[").append(record.getSourceClassName()).append(".");
        builder.append(record.getSourceMethodName()).append("] - ");
        builder.append("").append(record.getLevel()).append(" - ");
        builder.append(formatMessage(record));
        builder.append("\n");
        return builder.toString();
    }

    public String getHead(Handler h) {
        return super.getHead(h);
    }

    public String getTail(Handler h) {
        return super.getTail(h);
    }
}

Following is the way how the log messages will turn up in your log file.

25/03/2014 08:46:17.770 - [com.company.util.memcache.EntityThreadTask.setDataToMemcache] - INFO - thread05 compositekey set time : 5 ms
25/03/2014 08:46:17.781 - [com.company.util.memcache.EntityThreadTask.setDataToMemcache] - INFO - thread03 compositekey set time : 11 ms
25/03/2014 08:46:17.783 - [com.company.util.memcache.EntityThreadTask.setDataToMemcache] - INFO - thread05 compositekey set time : 12 ms
25/03/2014 08:46:17.785 - [com.company.util.memcache.EntityThreadTask.setDataToMemcache] - INFO - thread03 compositekey set time : 4 ms
25/03/2014 08:46:17.787 - [com.company.util.memcache.EntityThreadTask.setDataToMemcache] - INFO - thread05 compositekey set time : 4 ms

Monday, March 10, 2014

Fixing BSFException: unable to load language: java

I was using JMeter to execute BeanShell scripts that I have written and came across this exception. I had to waste sometime to find out what was the exact issue. Although I copied the BSF jar to the JMeter lib directory, it was not sufficient. When I added the bsh-bsf-2.0b4.jar, the script started running successfully. 

I thought someone else might find this tip useful, therefore blogging it.

Thursday, March 6, 2014

Fixing java.lang.ClassNotFoundException: org.apache.bsf.engines.java.JavaEngine

When using JMeter’s Java request sampler, I started seeing the below error.
2014/03/06 09:46:39 ERROR - org.apache.bsf.BSFManager: Exception : java.lang.ClassNotFoundException: org.apache.bsf.engines.java.JavaEngine
 at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
 at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
 at org.apache.bsf.BSFManager.loadScriptingEngine(BSFManager.java:693)
 at org.apache.jmeter.util.BSFTestElement.processFileOrScript(BSFTestElement.java:98)
 at org.apache.jmeter.visualizers.BSFListener.sampleOccurred(BSFListener.java:51)
 at org.apache.jmeter.threads.ListenerNotifier.notifyListeners(ListenerNotifier.java:84)
 at org.apache.jmeter.threads.JMeterThread.notifyListeners(JMeterThread.java:783)
 at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:443)
        at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:257)

Following steps will resolve this issue.

1. Remove existing bsf jar from the jmeter/lib directory
heshans@15mbp-08077:~/Dev/tools$ rm apache-jmeter-2.11/lib/bsf-2.4.0.jar

2. Download and extract BSF http://wi.wu-wien.ac.at/rgf/rexx/bsf4rexx/current/BSF4Rexx_install.zip.

3. Copy the following two jars to the jmeter/lib directory.
heshans@15mbp-08077:~/Dev/tools$ cp bsf4rexx/bsf-rexx-engine.jar apache-jmeter-2.11/lib/ 
heshans@15mbp-08077:~/Dev/tools$ cp bsf4rexx/bsf- apache-jmeter-2.11/lib/

Thursday, February 27, 2014

Fixing java.lang.NoClassDefFoundError: org/codehaus/classworlds/Launcher

I came across this error after I installed a new version of maven.
$ mvn -version
java.lang.NoClassDefFoundError: org/codehaus/classworlds/Launcher
Caused by: java.lang.ClassNotFoundException: org.codehaus.classworlds.Launcher
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: org.codehaus.classworlds.Launcher.  Program will exit.
Exception in thread "main"
The issue was with having two MAVEN_HOME locations (two versions) in the "path" variable. Once I removed a one, the issue resolved.
$ mvn -version
Apache Maven 3.1.1

Monday, February 24, 2014

Fixing mysql replication errors in a master/slave setup

If you have a mysql master/slave replication setup and have run into replication errors, you can follow the below instructions to fix up the replication break and sync up the data. 1) Stop mysql on the slave.
service mysql stop
2) Login to the master. 3) Lock the master by running the following command
mysql> flush tables with read lock;
NOTE: No date can be written at this time to the master, so be quick in the following steps if your site is in production. It is important that you do not close mysql or this running ssh terminal. Login to a separate ssh terminal for the next part. 4) Now, in a separate ssh screen, type the following command from the master mysql server.
rsync -varPe ssh /var/lib/mysql root@IP_ADDRESS:/var/lib/ —delete-after
5) After this is done, now you must get the binlog and position from the master before you unlock the tables. Run the following command on master
mysql> show master status\G;
Then you’ll get some information on master status. You need the file and the position because that’s what you’re going to use on the slave in a moment. See step 10 on how this information is used, but please do not skip to step 10. 6) Unlock the master. It does not need to be locked now that you have the copy of the data and the log position.
mysql> unlock tables;
7) Login to the slave now via ssh. First remove the two files : /var/lib/mysql/master.info and /var/lib/mysql/relay-log.info 8) Start mysql on the slave.
service mysqld start
9) Immediately login to mysql and stop slave
mysql> slave stop; 
10) Now, you have to run the following query filling in the information from the show master status above (Step 5.)
mysql> CHANGE MASTER TO MASTER_HOST=MASTER_IP,
mysql> MASTER_USER=‘replicate’, MASTER_PASSWORD=‘replicate’,
mysql> MASTER_LOG_FILE=‘mysql-bin.000001’, MASTER_LOG_POS=1234512351;
11) Now start the slave.
mysql > slave start
12) Check slave status.
mysql> show slave status\G;

Thursday, February 20, 2014

XML to XML tranformation using XSLT

In this example I am transforming an XML using XSLT by modifying certain child elements. In coming XML message:
<?xml version="1.0" encoding="utf-8"?><?xml-stylesheet type="text/xsl" href="/xsl/error.xsl"?>
<outtask_error>
    <server>
        <name>RSDC-C12</name>
    </server>
    <application>
        <name>Jobs</name>
        <version>2012_06_15</version>
        <prod_status>qa</prod_status>
        <datacenter_location>rtwa3</datacenter_location>
        <request_id>n6dft440-8049-4dff-982a-ee05abc8433</request_id>
    </application>
    <error time="2014-02-06T20:01:05" timezone="Pacific Standard Time">
        <error_id>aab10-825-4a52d-a261-7a845262f</error_id>
        <error_default_source>ICSYC</error_default_source>
        <request_id>b2263a40-8049-4dff-942a-ee05ef3f8433</request_id>
        <error_source>ICSync</error_source>
        <error_description>Connection Entity:abc no DB name is not configured</error_description>
        <stack_trace>at Company.Core.Sync.GetConnectionInfo...
        </stack_trace>
    </error>
    <server_variables>
        <param name="SERVER_NAME">RSDC-C12</param>
        <param name="SCRIPT_NAME">C:\Sync.exe</param>
        <param name="QUERY_STRING">Sync.exe Day1</param>
    </server_variables>
    <Error_Context>
        <param name="databasename">Company_MT</param>
        <param name="error_defaultsource">SYS</param>
        <param name="error_defaultapplicationname">Jobs</param>
        <param name="requestid">b8943a40-1349-4dff-232a-ee05ef523452342f</param>
        <param name="dbservername">fabc-sql02,1420</param>
    </Error_Context>
</outtask_error>
XSLT for the transformation:
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

    <xsl:output method="xml"/>

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>

    <xsl:template match="outtask_error/server_variables">
        <server_variables>
            <xsl:for-each select="param">
                <xsl:text disable-output-escaping="yes"><</xsl:text><xsl:value-of select="./@name"/><xsl:text disable-output-escaping="yes">></xsl:text>
                <xsl:value-of select="."/>
                <xsl:text disable-output-escaping="yes"><</xsl:text>/<xsl:value-of select="./@name"/><xsl:text disable-output-escaping="yes">></xsl:text>
            </xsl:for-each>
        </server_variables>
    </xsl:template>

    <xsl:template match="outtask_error/Error_Context">
        <Error_Context>
            <xsl:for-each select="param">
                <xsl:text disable-output-escaping="yes"><</xsl:text><xsl:value-of select="./@name"/><xsl:text disable-output-escaping="yes">></xsl:text>
                <xsl:value-of select="."/>
                <xsl:text disable-output-escaping="yes"><</xsl:text>/<xsl:value-of select="./@name"/><xsl:text disable-output-escaping="yes">></xsl:text>
            </xsl:for-each>
        </Error_Context>
    </xsl:template>

</xsl:stylesheet>
Out going XML:
<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="/xsl/error.xsl"?><outtask_error>
    <server>
        <name>RSDC-C12</name>
    </server>
    <application>
        <name>Jobs</name>
        <version>2012_06_15</version>
        <prod_status>qa</prod_status>
        <datacenter_location>rtwa3</datacenter_location>
        <request_id>n6dft440-8049-4dff-982a-ee05abc8433</request_id>
    </application>
    <error time="2014-02-06T20:01:05" timezone="Pacific Standard Time">
        <error_id>aab10-825-4a52d-a261-7a845262f</error_id>
        <error_default_source>ICSYC</error_default_source>
        <request_id>b2263a40-8049-4dff-942a-ee05ef3f8433</request_id>
        <error_source>ICSync</error_source>
        <error_description>Connection Entity:abc no DB name is not configured</error_description>
        <stack_trace>at Company.Core.Sync.GetConnectionInfo...
        </stack_trace>
    </error>
    <server_variables><SERVER_NAME>RSDC-C12</SERVER_NAME><SCRIPT_NAME>C:\Sync.exe</SCRIPT_NAME><QUERY_STRING>Sync.exe Day1</QUERY_STRING></server_variables>
    <Error_Context><databasename>Company_MT</databasename><error_defaultsource>SYS</error_defaultsource><error_defaultapplicationname>Jobs</error_defaultapplicationname><requestid>b8943a40-1349-4dff-232a-ee05ef523452342f</requestid><dbservername>fabc-sql02,1420</dbservername></Error_Context>
</outtask_error>