Groovy: Overloading [] and dot .

class Konf {

    // Initializing overloader
    static {

        // . read
        Konf.metaClass.getProperty = { String prop ->
            println "getProp $prop"

            this."${prop}"        

        }

        // . assignment
        Konf.metaClass.setProperty = { String prop, val ->
            println "setProp $prop $val"            

            this.metaClass."${prop}" = val
        }
    }

    // [] read
    def getAt( String key ) {
        println 'getAt'
        this."${key}"    

    }

    // [] set
    def putAt( String key, val ) {
        println "putAt $key $val" 

        this.metaClass."${key}" = val
    }

    def clear() {

    }
}

Restore MySQL Replication Failure

RESET SLAVE

START SLAVE UNTIL SQL_AFTER_MTS_GAPS

SET @@GLOBAL.slave_parallel_workers = 0

START SLAVE SQL_THREAD

Enable/Disable Windows Network Interface

Disable
netsh interface set interface name="Local Area Connection" admin=disabled

Enable
netsh interface set interface name="Local Area Connection" admin=Enabled

Reset
netsh interface set interface name="Local Area Connection" admin=disabled & netsh interface set interface name="Local Area Connection" admin=Enabled

Spring Roo 1.2.4, Spring Security 3.1

Customizing voters:

public class MyRightVoter extends RoleVoter implements AccessDecisionVoter
{
    public int vote( Authentication authentication, Object object,
Collection attributes )
    {}
}

Defining proper access decision manager and adding customized voter to it:
* To override http decision manager beans must be added to applicationContext-security.xml and for method based in controller must be added in webmvc-config.xml and add to it.

Adding new decision manager for method and http handling:

* aspectj mode is used when want to add security to our aspects like roo generated aspect (new aspect should be defined to annotate security to methods), this mode should be defined in applicationContext-security.xml, this global definition doesn't require to reference acess-decision-manage, as the main one that is in use, defined in webmvc-config.xml


* It is possible to customize authentication to return customized authority of users by implementing getAuthorities() method.

 * Don't forget to add the following item to spring/webmvc-config.xml to use annotation in spring controllers

Get Relative Path of Application Context

def s = ctx.grailsLinkGenerator

s.contextPath

s.serverBaseURL


The service is in the following package :
org.codehaus.groovy.grails.web.mapping.LinkGenerator

Use Services in Grails Shell/Console

def svc = ctx.getBean('serviceName')

def svc = ctx.serviceName

My Experience on Migrating a Database

I have a server that runs both application and database and all resources are utilized on peak time, so I migrated the database to 2 other new servers with more capacity.

It is about the whole story from OS installation to DB migration and the challenges on the way.

Use raid controller for mirroring 1st 2 disks for / and /boot.
The final layout of the root partitions is as:

sda 557.9G  0 disk
sda1 200M  0 part   /boot/efi
sda2 500M  0 part   /boot
sda3 557.2G  0 part
g_root-lv_root 424G  0 lvm    /
g_root-lv_swap 16G  0 lvm    [SWAP]
vg_root-lv_varlog 19.5G  0 lvm    /var/log
vg_root-lv_home 97.7G  0 lvm    /home

The /boot/efi may appear new that is because of using UEFI mode of BIOS boot agent.

Clearing old partitions of other disks after installing OS (RHEL):

For each disk that has partition
fdisk /dev/sd? -> p ->d -> w
or
dmsetup remove /dev/mapper/ddf???????????????????????


LVM:
pvcreate /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg
vgcreate -s 16M vg_data /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf
lvcreate --type raid6 -i 3 -L 1.5T -n lv_mysql vg_data
mkfs.ext4 /dev/mapper/vg_data-lv_mysql

Mounting Permanently:
/etc/fstab
/dev/mapper/vg_data-lv_mysql /data/mysql        ext4    defaults        1 2

SE Linux:
install semanage
yum install policycoreutils-python-2.0.83-19.47.el6.x86_64

Adding permission for new customized directory of mysql
semanage fcontext -a -t mysqld_db_t "/data/mysql(/.*)?"
restorecon -R -v /data/mysql

Firewall:
yum install system-config-firewall-1.2.27-7.1.el6.noarch

iptables -I INPUT 4 -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT
service iptables status
service iptables save

Note: -I INPUT 4 is putting this rule before the global rejection rule that is there by default, The status should be checked and ensure about the position of the rule, here 4.


MySQL:
Update /etc/my.cnf
mysql_install_db --defaults-file=/etc/my.cnf --user=mysql
service mysql start

Grant options for defining replication on both servers
mysql  -p -h 127.0.0.1 -P3306 -u root -e "GRANT ALL ON *.* TO root@'%' WITH GRANT OPTION;"

Install mysql utilities
yum install mysql-connector-python-2.1.1-1.el6.noarch.rpm
yum install mysql-utilities-commercial.noarch

mysqlreplicate --master=root@10.1.196.4:3306 --slave=root@10.1.196.12:3306 --rpl-user=rpl:sLavep@ss

Note: the --rpl-user values will be created automatically, no need to define that user.

Checking Replication Status:
mysqlrplcheck --master='root@10.1.196.4:3306' --slave='root@10.1.196.12:3306'

mysqlrplshow --master='root@10.1.196.4:3306' --discover-slaves-login='root'

Master Only:
mysql_secure_installation
mysql>
update mysql.user set user = 'dba', password=Password('123456'), host = '%' where user = 'root' and host = '::1';
SET sql_log_bin = 0;
delete from mysql.user where user = 'root';
SET sql_log_bin = 1;
flush privileges;

Note: SET sql_log_bin can stop/start replication of the current session.

SLAVE:
SET sql_log_bin = 0;
delete from mysql.user where user = 'root';
delete from mysql.user where host = 'hostname' and user = '';
SET sql_log_bin = 1;
flush privileges;

Checking replication status:
show slave status \G

Fixing replication failures:
Running empty transaction for failed transaction id (GTID)

SLAVE:
If there is error:
show slave status \G;
SET GTID_NEXT="2e82f8b8-cc26-11e4-bb69-0010e02446b8:3"
BEGIN; COMMIT;
SET GTID_NEXT="AUTOMATIC";
STOP SLAVE;
START SLAVE;
or
SET GLOBAL sql_slave_skip_counter = 1;

Redirecting old server processes to new DB server:
vi ~/.my.cnf
[client]
user=dba
password=123456
host=10.1.196.4

chmod og-rwx,u-w ~/.my.cnf

DB Migration:
Export:
mysqldump  --tab=./System/ System_db
mysqldump  --tab=./db2/ db2
mysqldump  --tab=./Dimension/ Dimension

Statistics Database:
mysqldump  --tab=./stat/ --no-data CS3_Statistics

Note: --no-data is used because I don't want to migrate all tables data in this phase

mysqldump  --tab=./stat/ --ignore-table=Statistics.ProcessStatistics --ignore-table=Statistics.Log --ignore-table=Statistics.Statistics_System  --ignore-table=Statistics.ServerIf --single-transaction Statistics &> /tmp/dump.log &

Note: --single-transaction is used to  prevent table lock.

Import:
mysqladmin create System_db
mysqladmin create db2
mysqladmin create Dimension
mysqladmin create Statistics

cat *.sql | mysql System_db
repeat for each db export

Note: In some cases that you have a view or foreign key you should ensure the order of sql and txt files to keep consistency. This order is not keeping by use *.sql or *.txt and you may need to list files manually.

mysqlimport --local Dimension Dimension/*.txt

MySQL Proxy:
stop old database server to free the listen port

Run mysql proxy to redirect connections to new server
./bin/mysql-proxy  --defaults-file=my.cnf