Package now is a time toolkit for golang.

time.now() // 2013-11-18 17:51:49.123456789 mon
beginningofminute() // 2013-11-18 17:51:00 mon
beginningofhour() // 2013-11-18 17:00:00 mon
beginningofday() // 2013-11-18 00:00:00 mon
beginningofweek() // 2013-11-17 00:00:00 sun
firstdaymonday = true // set monday as first day
beginningofweek() // 2013-11-18 00:00:00 mon
beginningofmonth() // 2013-11-01 00:00:00 fri
beginningofquarter() // 2013-10-01 00:00:00 tue
beginningofyear() // 2013-01-01 00:00:00 tue
endofminute() // 2013-11-18 17:51:59.999999999 mon
endofhour() // 2013-11-18 17:59:59.999999999 mon
endofday() // 2013-11-18 23:59:59.999999999 mon
endofweek() // 2013-11-23 23:59:59.999999999 sat
firstdaymonday = true // set monday as first day
endofweek() // 2013-11-24 23:59:59.999999999 sun
endofmonth() // 2013-11-30 23:59:59.999999999 sat
endofquarter() // 2013-12-31 23:59:59.999999999 tue
endofyear() // 2013-12-31 23:59:59.999999999 tue
// use another time
t := time.date(2013, 02, 18, 17, 51, 49, 123456789, time.utc)
new(t).endofmonth() // 2013-02-28 23:59:59.999999999 thu
monday() // 2013-11-18 00:00:00 mon
sunday() // 2013-11-24 00:00:00 sun
endofsunday() // 2013-11-24 23:59:59.999999999 sun
this package contains the source.