wls: How to manually test a DataSource connection

When you creating new DataSource in WLS, it allows you to test the connectivity. However after you have created it, the test button is kinda hidden in a non-obvious way. This is how I get to it and test an existing DataSource that have targeted a server.

1. Login to Admin Console (eg: http://localhost:7100/console)
2. On the Domain Structure left panel, click:
    <my_domain_name> (eg: DefaultDomain) > Services > Data Sources
3. On the right, Click on the DataSource name you want to test.
4. Click the "Monitoring" tab > "Testing" tab.
5. Select the server the DataSource has targeted to and then press "Test Data Source" button.

hg: How to setup repository on a remote server

I love using mercurial source control! It's easy to use and it works as I expected everytime I need to do something with my source repository. Here is how you can quickly create a remote repository to push your existing project into it. (use this as backup of your project or share among your team etc)

1. SSH into your remote server and create an empty repository.
ssh remote_hostname
bash> cd $HOME
bash> mkdir -p hg-repos/myproject
bash> cd hg-repos/myproject
bash> hg init

2. Back on your local machine and in your existing hg project, edit the .hg/hgrc file with the following:

[paths]
default=ssh://remote_hostname/hg-repos/myproject
[ui]
remotecmd=/usr/local/bin/hg

That's it! You don't even need hg server running in remote host to make this work! Now you may perofrm "hg push" command inside your local project to sync up to remote host

NOTE 1: This setup rely on your SSH into remote host. If you want to avoid user password promt everytime you perform "hg push", then setup Key-Based SSH login.

NOTE 2: You only need "remotecmd" part if your remote_hostname does not have a standard hg installed. Then you can specified your custom location here.

NOTE 3: If you want to use abolute path for "default" path instead, then you can use double slash after the "remote_hostname". Else the single slash is relative to your $HOME directory.

Java Jdbc Test for UTF8 and Default Value for TIMESTAMP

Just a quick MySQL test on how to use UTF8 encoding with JDBC connection string. Also a test on how to set TIMESTAMP default values.

package zemian.jdbc;

import org.junit.Test;

import java.sql.*;
import java.util.*;
import java.util.Date;

/**

 -- drop table ztest_issues;
 CREATE TABLE ztest_issues(
 id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
 , title VARCHAR(64) NOT NULL
 , summary TEXT NULL
 , priority INT NOT NULL DEFAULT 5
 , cdate DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
 );

 INSERT INTO ztest_issues(title) VALUES('test');
 INSERT INTO ztest_issues(title, summary) VALUES('test2', 'Just a test');
 INSERT INTO ztest_issues(title, summary, priority) VALUES('test2', 'Just a test', 1);
 INSERT INTO ztest_issues(title, summary, priority, cdate) VALUES('test2', 'Just a test', 1, '2010-12-31 08:00:00');

 --INSERT INTO ztest_issues(title, summary) VALUES('locale test1', LOAD_FILE('C:/data/tmp/test.xml'));
 --INSERT INTO ztest_issues(title, summary) VALUES('locale test2', LOAD_FILE('C:/data/tmp/test2.xml'));
 --INSERT INTO ztest_issues(title, summary) VALUES('locale test3', LOAD_FILE('C:/data/tmp/test3.xml'));

 SELECT * FROM ztest_issues;

 NOTE:
 CURRENT_TIMESTAMP is version specific and is now allowed for DATETIME columns as of version 5.6 http://dev.mysql.com/doc/refman/5.6/en/timestamp-initialization.html

 For 5.6 <, use TIMESTAMP for cdate field instead.

 cdate TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
 cdate DATETIME NULL

 NOTE2:
 cdate DATETIME NOT NULL DEFAULT 0

 If you were to use default to ZERO, then you would need this properties in conn string. Else you will fail to get ZERO date value into Java.

 You need to tell the JDBC driver to convert them to NULL. This is done by passing a connection property name zeroDateTimeBehavior with the value convertToNull

 For more details see the manual: http://dev.mysql.com/doc/refman/4.1/en/connector-j-installing-upgrading.html

 */
public class ZtestIssuesJdbcTest {
//    String url = "jdbc:mysql://localhost/test";
//    String url = "jdbc:mysql://localhost/test?zeroDateTimeBehavior=convertToNull";
    String url = "jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=UTF-8&connectionCollation=utf8_general_ci&zeroDateTimeBehavior=convertToNull";
    String username = "test";
    String password = "test123";

    @Test
    public void testShowTableLocale() throws Exception {
        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            String sql = "SHOW VARIABLES LIKE 'char%'";
            System.out.println("Sql:" + sql);
            Statement sm = conn.createStatement();
            ResultSet rs = sm.executeQuery(sql);
            while (rs.next()) {
                System.out.printf("%s\t%s\n", rs.getObject(1), rs.getObject(2));
            }

            sql = "SHOW CREATE TABLE ztest_issues";
            System.out.println("Sql:" + sql);
            sm = conn.createStatement();
            rs = sm.executeQuery(sql);
            while (rs.next()) {
                System.out.printf("%s\t%s\n", rs.getObject(1), rs.getObject(2));
            }
        }
    }

    @Test
    public void testQuery() throws Exception {
        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            String sql = "SELECT id, cdate, title, summary FROM ztest_issues";
            System.out.println("Sql:" + sql);
            Statement sm = conn.createStatement();
            ResultSet rs = sm.executeQuery(sql);
            while (rs.next()) {
                System.out.printf("%d\t%s\t%s\t%s\n", rs.getObject(1), rs.getObject(2), rs.getObject(3), rs.getObject(4));
            }
        }
    }

    @Test
    public void testInsert() throws Exception {
        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            String sql = "INSERT INTO ztest_issues(title, summary, cdate) VALUES(?, ?, ?)";
            System.out.println("Sql: " + sql);
            PreparedStatement ps = conn.prepareStatement(sql);

            String testId = "" + System.currentTimeMillis();

            ps.setObject(1, "English Locale " + testId);
            ps.setObject(2, "Just a test");
            ps.setObject(3, new Date());
            int result = ps.executeUpdate();
            System.out.println("Insert Result: " + result);

            ps.setObject(1, "Chinese Locale " + testId);
            ps.setObject(2, "只是一個測試");
            ps.setObject(3, new Date());
            result = ps.executeUpdate();
            System.out.println("Insert Result: " + result);

            ps.setObject(1, "Spanish Locale " + testId);
            ps.setObject(2, "Sólo una prueba");
            ps.setObject(3, new Date());
            result = ps.executeUpdate();
            System.out.println("Insert Result: " + result);
        }
    }
}

ConEmu - a Terminal Windows or Tab Manager

Just learned about ConEmu project at https://conemu.github.io and it's pretty awesome!

Thanks Onur for the tips!

mac: How to view Unix man pages with browser

I have come across this wonderful project called Bwana (https://www.bruji.com/bwana/) for Mac. Install it and you can view any man page on the browser. For example try typing the following address on the Safari:

man:find

And you will see something like this:

python: How to setup a new Trac issue tracking system

Here is how I setup a local instance of Trac (a python based issue tracking web application) on my Mac.

Prerequisite: MySQL 5.6 and Python 2.7 (Python3 will not work with Trac yet!)

Step1: Setup a Trac database and a user

sql> CREATE DATABASE trac DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
sql> CREATE USER 'dev'@'localhost' IDENTIFIED BY 'dev123';
sql> GRANT ALL ON trac.* TO 'dev'@'localhost';

Step2: Install MySQL adaptor for Python and Trac

bash> pip install Genshi trac mysqlclient

Step3: Setup a Track instance

bash> trac-admin /Users/zemian/dev/mytrac intent

bash> # Above will prompt you to enter a backend string. Use
bash> # this connection string: 

bash> #   mysql://dev:dev123@localhost:3306/trac

Step3: Create a Trac admin user

bash> htpasswd -c /Users/zemian/dev/mytrac/.htpasswd admin

Step4: Run Track

bash> tracd -p 8000 --basic-auth="mytrac,/Users/zemian/dev/mytrac/.htpasswd,mytrac" /Users/zemian/dev/metric

python: mysqlclient gives "Library not loaded: libmysqlclient.18.dylib" error

If you want to use python MySQLdb module (eg: if you run Trac with MySQL backend), you would need first install MySQL server on MacOSX, then install the mysqlclient python package using pip. However upon verifying it, you may encounter error like this:

(mypy-test)Zemians-Air:dev zemian$ pip install mysqlclient

Collecting mysqlclient

  Using cached mysqlclient-1.3.6.tar.gz

Building wheels for collected packages: mysqlclient

  Running setup.py bdist_wheel for mysqlclient

  Stored in directory: /Users/zemian/Library/Caches/pip/wheels/9c/3b/73/8f16f45dc76999dafc2af06b0d6e1e669bc0e1594f41fcc2e8

Successfully built mysqlclient

Installing collected packages: mysqlclient

Successfully installed mysqlclient-1.3.6

(mypy-test)Zemians-Air:dev zemian$ python

Python 2.7.10 (default, Aug 22 2015, 20:33:39) 

[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.1)] on darwin

Type "help", "copyright", "credits" or "license" for more information.

>>> import MySQLdb

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/Users/zemian/dev/mypy-test/lib/python2.7/site-packages/MySQLdb/__init__.py", line 19, in <module>

    import _mysql

ImportError: dlopen(/Users/zemian/dev/mypy-test/lib/python2.7/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib

  Referenced from: /Users/zemian/dev/mypy-test/lib/python2.7/site-packages/_mysql.so

  Reason: image not found

To resolve this, you need to add the following to your shell environment

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib

Update 2016-06-17
To install mysqlclient on Ubuntu 14, you might need to first install the mysql_config first:
  bash> sudo apt-get install libmysqlclient-dev