The "George White Scandals" were a series of annual Broadway Revues similar to the Ziegfield Follies. They ran from 1919 until 1939. Large numbers of singers, dancers, motion picture actors and instrumentalists had their beginnings in these revues including the famous Ukulele virtuoso Cliff Edwards, who appeared in all of them from 1930 on. Our song was introduced by and launched the career of Ethel Merman - the greatest of all American Musical Theatre leading ladies. But Rudy Vallee another star of the pre-WW2 crooners also sang it.
The phrase is defined in the English Cambridge Dictionary as meaning that "Life is sweet" - but equally it can also be used to mean the direct opposite!

Note symbol ^ = M or Major eg Eb^ = Eb Major
Eb^7 = Eb Major 7