Analyze logfile & take action, Linux Scripting

There is an application running which generates log file. We need to create some script which will check for errors in the logfile do the following: 1. Tail last 10 minutes of log file |grep only the rows which contain specific word 2. from the output we need to fetch 2 variables - "username" & "IP", as it is both variables we need to sed next words after specific patterns 3. the output will look like user1 1.1.1.1 user2 2.2.2.2 user3 3.3.3.3 user1 1.1.1.1 user4 4.4.4.4 4. If the username exists more than "X" times in the final output take action - ban IP for specific time & send email to email address fetched from db mysql [login to view URL] where username = $user & write some info to mysql [login to view URL] where username = $user The script must be optimized, not memory or cpu hungry, will be run each 10 min in cron job, so please only experienced users who know what to do. thank you