It's not a diary, it's a movie.

Diary of a Wimpy Kid (2010)

Directed by Thor Freudenthal

Greg Heffley is headed for big things, but first he has to survive the scariest, most humiliating experience of any kid’s life – middle school! That won’t be easy, considering he’s surrounded by hairy-freckled morons, wedgie-loving bullies and a moldy slice of cheese with nuclear cooties!