In my opinion, not getting angry is impossible. No matter how much meditation you practice or how happy you are in your life. Getting angry is inevitable. Anger for me is nothing but normal human emotion. It's ok to be angry, it's ok to feel frustrated or depressed in certain situations. If you live in a social world then anger is as normal as laughter. period.
Aristotle (father of political science) once said "Anybody can become angry, that is easy, but to be angry with the right person and to the right degree and at the right time and for the right purpose, and in the right way — that is not within everybody's power and is not easy."
The best way to control your anger is by being aware. The more you are aware of yourself, the more you can control and channelise your anger into something productive. Always remember that if someone makes you angry, you already become his/her prisoner. Just by avoiding 1 minute of anger, you can create 10 years of peace.
As Maya Angelou once said
"Bitterness is like cancer. It eats upon the host. But anger is like fire. It burns it all clean."