half work

util.go

@@ -0,0 +1,30 @@
+package main
+
+import "fmt"
+import "os"
+import "runtime"
+import "path/filepath"
+
+// Go is a basic promise implementation: it wraps calls a function in a goroutine
+// and returns a channel which will later return the function's return value.
+func Go(f func() error) chan error {
+	ch := make(chan error)
+	go func() {
+		ch <- f()
+	}()
+	return ch
+}
+
+// if os.env DEBUG set, debug is on
+func Debugf(format string, a ...interface{}) {
+	if os.Getenv("DEBUG") != "" {
+		_, file, line, ok := runtime.Caller(1)
+		if !ok {
+			file = "<unknown>"
+			line = -1
+		} else {
+			file = filepath.Base(file)
+		}
+		fmt.Fprintf(os.Stderr, fmt.Sprintf("[debug] %s:%d %s\n", file, line, format), a...)
+	}
+}