Hope this is it:

The Last Post
Robert Graves
From http://www.bartleby.com/103/177.html

The bugler sent a call of high romance
"Lights out! Lights out!" to the deserted square
On the thin brazen notes he threw a prayer:
"God, if it's this for me next time in France,
O spare the phantom bugle as I lie
Dead in the gas and smoke and roar of guns,
Dead in a row with other broken ones,
Lying so stiff and still under the sky
Jolly young Fusiliers, too good to die..."
The music ceased, and the red sunset flare
Was blood about his head as he stood there.

Music in MIDI^^