1. Gratulation! = congratulations!
2. Gratulationen mein Freund! = congratulations (my) friend!
3. Ich gratuliere dir! (+mein Freund!) = I congratulate you! (+my friend!)
I think 3. is usable in all circumstances and therefor favorable.
Assuming you mean "how" to say happy in German, there are a couple of different ways: Froh and gluecklich.
In Hawaiian, you can say "Palena Pōtu" to express "happy graduation." Another common phrase is "E mālama i ka lā," which means "Take care on your day," referring to the graduation celebration. These expressions convey joy and well-wishes for someone's graduation achievement.
Happy Friday in German is glücklicher Freitag
happy - glücklich Also fröhlich, froh
In Pennsylvania German, you can say "Ei glickliche Geburdsdaag!" to wish someone a happy birthday.
I am not a happy puppy is an English idiom and cannot be translated into German in a way that conveys it's meaning.
happy married life = glückliches Eheleben
"Happy Saint Patrick´s Day" in German is: Fröhlichen St. Patricks Tag
Frohes Neues Jahr.
Die glücklichen Kinder.
I am not so happy = ich bin nicht so glücklich
Somebody to Love is the song during the graduation scene in Happy Feet.