# A label is treated as content of the channel its arrow routes through. In
# route: orthogonal mode the vertical run travels the gap between the two
# columns, so that gap widens to hold the text — the columns spread apart and
# the label never overlaps a box (just as a long node label grows its box).
grid {
  label: "Request flow"
  ui   { label: "UI" }                 api { label: "API" anchors: [out] }
  page { label: "Page" }               svc { label: "Service" }
  db   { label: "DB" anchors: [in] }   log { label: "Log" }
}

@layout {
  route: orthogonal
  margin: 16
  grid { cols: 2 }
  grid.ui   {col:1; row:1}  grid.api {col:2; row:1}
  grid.page {col:1; row:2}  grid.svc {col:2; row:2}
  grid.db   {col:1; row:3}  grid.log {col:2; row:3}
  grid.api { anchor out: [0.0, 0.5] }   # left edge of API
  grid.db  { anchor in:  [1.0, 0.5] }   # right edge of DB
}

grid.api#out --> grid.db#in { label: "lookup user" }