02 May 2016

WebLogic access log files

Many times in development side, we want to access log files for a remote weblogic.
One easy way (to avoid several constraints) is to have like-a webpage to see these files.

This can be achieved easily with weblogic.xml parameters:

Different WebLogic Server Tools
Bunch of tools to help WLS admin, debugging, etc.
  1. This first version is a war file to access log files from remote client through an HTML file generated by WLS.
  2. the core idea is to show the directories/files of a particular server, this way we can debug easily. 
https://github.com/devwebcl/wls_contraption

The weblogic.xml is:

 <?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-web-app xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-web-app" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd http://xmlns.oracle.com/weblogic/weblogic-web-app http://xmlns.oracle.com/weblogic/weblogic-web-app/1.3/weblogic-web-app.xsd">
    <wls:weblogic-version>10.3.6</wls:weblogic-version>
    <wls:context-root>logs_retrieval</wls:context-root>
   
<!--

/u01/domains1036/MYDOMAIN/logs
/u01/domains1036/MYDOMAIN/servers/SERVER1/logs


/ u01/ domains1036/ MYDOMAIN/ apps/ app1-wl/ dist/ app1. ear
/ u01/ domains1036/ MYDOMAIN/ apps/ app2-auth/ dist/ app2. war

error_web.log :
/tmp

----

 index-directory-enabled

The <index-directory-enabled> element controls whether or not to automatically generate an HTML directory listing if no suitable index file is found.
The default value is false (does not generate a directory). Values are true or false.
https://docs.oracle.com/cd/E28280_01/web.1111/e13712/weblogic_xml.htm#WBAPP596

  -->
    <wls:container-descriptor>
        <wls:index-directory-enabled>true</wls:index-directory-enabled>
    </wls:container-descriptor>

    <wls:virtual-directory-mapping>
        <wls:local-path>/u01/domains1036/MYDOMAIN</wls:local-path>
        <wls:url-pattern>/servers/logs/*</wls:url-pattern>
    </wls:virtual-directory-mapping>

    <wls:virtual-directory-mapping>
        <wls:local-path>/u01/domains1036/MYDOMAIN/</wls:local-path>
        <wls:url-pattern>/logs/*</wls:url-pattern>
    </wls:virtual-directory-mapping>

    <!-- depending on OS we must use : "/" or "c:" -->
    <wls:virtual-directory-mapping>
        <!-- wls:local-path>c:/</wls:local-path -->
        <wls:local-path>/</wls:local-path>
        <wls:url-pattern>/tmp/*</wls:url-pattern>
    </wls:virtual-directory-mapping>
   
   
    <wls:jsp-descriptor>
      <wls:page-check-seconds>0</wls:page-check-seconds>
    </wls:jsp-descriptor>
    <wls:container-descriptor>
      <wls:servlet-reload-check-secs>0</wls:servlet-reload-check-secs>
      <wls:resource-reload-check-secs>0</wls:resource-reload-check-secs>
    </wls:container-descriptor>

</wls:weblogic-web-app>


07 April 2016

Fowler's ideas

Interesting posts from Martin Fowler, most are his ideas, however there some that is referring to third idea... as usual, it is referenced correctly in his document:

- CQRS
- Event Sourcing
- Parallel Model
- ReportingDatabase

...

16 March 2016

Catastrophic Backtracking

RegExp Playground

This repository contains several regexp examples.

Examples

1. Catastrophic Backtracking

This is Java example of backtracking catastrophic shown in Coding Horror post This is a known behavior when using nesting repetition operators, that has been analyzed in stackoverlow, regular expressions dedicated sites.
It can be seen the exponential explosion that take to parse using regexp for a simple pattern:
(x+x+)y+
Details of this issue can be found on the above links.

Execute

mvn clean package
mvn exec:java -Dexec.mainClass="cl.devweb.regexp.exploit.CatastrophicBacktracking"

Rule of Thumb - Solution

The solution is simple. When nesting repetition operators, make absolutely sure that there is only one way to match the same match. If repeating the inner loop 4 times and the outer loop 7 times results in the same overall match as repeating the inner loop 6 times and the outer loop 2 times, you can be sure that the regex engine will try all those combinations.

OUTPUT

 mvn exec:java -Dexec.mainClass="cl.devweb.regexp.exploit.CatastrophicBacktracking"
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building regexp-exploit 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- exec-maven-plugin:1.4.0:java (default-cli) @ regexp-exploit ---
Found value: xxxxxxxxxxxxxy  timer=113.2 μs
Invalid match of 1 chars took 20.97 μs
Invalid match of 2 chars took 14.28 μs
Invalid match of 3 chars took 21.82 μs
Invalid match of 4 chars took 149.2 μs
Invalid match of 5 chars took 26.92 μs
Invalid match of 6 chars took 43.73 μs
Invalid match of 7 chars took 80.80 μs
Invalid match of 8 chars took 135.6 μs
Invalid match of 9 chars took 207.1 μs
Invalid match of 10 chars took 240.6 μs
Invalid match of 11 chars took 442.9 μs
Invalid match of 12 chars took 848.0 μs
Invalid match of 13 chars took 1.623 ms
Invalid match of 14 chars took 2.504 ms
Invalid match of 15 chars took 4.339 ms
Invalid match of 16 chars took 8.163 ms
Invalid match of 17 chars took 16.60 ms
Invalid match of 18 chars took 33.27 ms
Invalid match of 19 chars took 69.98 ms
Invalid match of 20 chars took 138.2 ms
Invalid match of 21 chars took 268.9 ms
Invalid match of 22 chars took 537.9 ms
Invalid match of 23 chars took 977.8 ms
Invalid match of 24 chars took 2.132 s
Invalid match of 25 chars took 4.260 s
Invalid match of 26 chars took 8.433 s
Invalid match of 27 chars took 17.18 s
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 34.977 s
[INFO] Finished at: 2016-03-16T12:38:59-03:00
[INFO] Final Memory: 9M/245M
[INFO] ------------------------------------------------------------------------
We can see taking a Thread Dump, where is spending (wasting?) most of the time:
"main" #1 prio=5 os_prio=31 tid=0x00007f8f9a006000 nid=0x1303 runnable [0x000000010a718000]
   java.lang.Thread.State: RUNNABLE
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.match(Pattern.java:4785)
    at java.util.regex.Pattern$GroupTail.match(Pattern.java:4717)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$Curly.match0(Pattern.java:4272)
    at java.util.regex.Pattern$Curly.match(Pattern.java:4234)
    at java.util.regex.Pattern$GroupHead.match(Pattern.java:4658)
    at java.util.regex.Pattern$Loop.matchInit(Pattern.java:4801)
    at java.util.regex.Pattern$Prolog.match(Pattern.java:4741)
    at java.util.regex.Pattern$Start.match(Pattern.java:3461)
    at java.util.regex.Matcher.search(Matcher.java:1248)
    at java.util.regex.Matcher.find(Matcher.java:637)
    at cl.devweb.regexp.exploit.CatastrophicBacktracking.main(CatastrophicBacktracking.java:81)

TODO

  • add more examples :)

License

MIT . .

15 March 2016

Maven Cheat Sheet

Some reminder for Maven:

1. Use a different settings.xml
mvn --settings ~/.m2/YourOwnSettings.xml clean install
or
mvn -s ~/.m2/YourOwnSettings.xml clean install

2. Jboss tasks:
 mvn jboss-as:deploy
 mvn jboss-as:redeploy
 mvn jboss-as:undeploy

3. Eclipse Maven clean:
(retired)
mvn eclipse:eclipse
mvn eclipse:clean
mvn install

4. set java version:
<project>
 [...]
 <build>
 [...]
 <plugins>
 <plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>3.5.1</version>
 <configuration>
 <source>1.4</source>
 <target>1.4</target>
 </configuration>
 </plugin>
 </plugins>
 [...]
 </build>
 [...]
</project>

5. Missing Maven dependencies in Eclipse Project

   workaround to have an eclipse maven project

6. basic maven structure:
   src/main/java
7. packaging:

<packaging>jar</packaging>

8. executing from maven:

add the following plugin to pom.xml:
<plugin>
 <groupId>org.codehaus.mojo</groupId>
 <artifactId>exec-maven-plugin</artifactId>
 <version>1.2.1</version>
 <configuration>
 <mainClass>com.myorganisationname.common.App</mainClass>
 </configuration>
 </plugin>

and run it with:


mvn exec:java

9. skipping test:


<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19.1</version>
<configuration>
<skipTests>true</skipTests>
</configuration>
</plugin>
 

 
10. Multiple Module Projects
<packaging>pom</packaging>


<modules>
<module>guide-ide-eclipse-site</module>
<module>guide-ide-eclipse-core</module>
<module>guide-ide-eclipse-module1</module>
</modules>


Add the parent to the POMs of the new modules:
 <parent>
 <groupId>guide.ide.eclipse</groupId>
 <artifactId>guide-ide-eclipse</artifactId>
 <version>1.0-SNAPSHOT</version>
 </parent>


mvn install
mvn eclipse:eclipse

http://maven.apache.org/plugins/maven-eclipse-plugin/reactor.html


11. web archetype

mvn archetype:generate -DgroupId=cl.devweb -DartifactId=wls_log_retrieval -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false




08 March 2016

Logging of class loading and unloading.

There are several useful system properties for JVM that are not very popular.

One of those is:

-verbose:class

This helps to printout all the jar files that are being used when running classes.

i.e.:
 [Opened /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.Object from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.io.Serializable from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.Comparable from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.CharSequence from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.String from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.reflect.AnnotatedElement from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.lang.reflect.GenericDeclaration from /Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk/Contents/Home/jre/lib/rt.jar]
Another approach is to printout in the code itself using ClassLoader (but this is more intrusive).

  ClassLoader cl = ClassLoader.getSystemClassLoader();

  URL[] urls = ((URLClassLoader)cl).getURLs();

  for(URL url: urls){
     System.out.println(url.getFile());
  }
 
 

02 March 2016

Sherlock Holmes Quotes

Interesting quotes from Sherlock Holmes:

From movie Mr. Holmes (2015)

I haven't a clue.
One can't solve everything.

 
From book A Scandal in Bohemia
It is a capital mistake to theorize before one has data

01 March 2016

TeX file to PDF

We have two easy ways to achieve this

1. Go to a longer (but safer) path:

tex --> dvi --> ps --> pdf

By using:

tex example.tex
dvips example.dvi
ps2pdf example.ps

2. or using a straightforward tool:


pdftex example.tex


In both scenarios you'll get a PDF file.

Give it a try with several TeX files at Knuth's

29 February 2016

The Scrum Field Guide

I have won a free book from coderanch. After asking a politic question, I am going to receive it.
Interesting book, and even more interesting was the thread I had with the author (Mitch).

UPDATE1 (30.03.2016) I received the book

http://www.coderanch.com/t/662440/Agile/Scrum-Field-Guide-scope

http://www.coderanch.com/t/662632/Agile/Winners-Scrum-Field-Guide

Image from http://ecx.images-amazon.com

 

27 February 2016

Erase una vez...

Mandarinas y naranjas para las monjas de la granja, pan con queso para el diablo leso, esterines y esterones para los diablos orejones...

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The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.