beam/examples/beamsh: scripts can be passed as filenames

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)

beam/examples/beamsh/beamsh.go

@@ -25,6 +25,7 @@ func main() {
 		Fatal(err)
 	}
 	defer devnull.Close()
+	if len(os.Args) == 1 {
 		if term.IsTerminal(0) {
 			input := bufio.NewScanner(os.Stdin)
 			for {
@@ -39,7 +40,9 @@ func main() {
 						fmt.Fprintf(os.Stderr, "error: %v\n", err)
 						continue
 					}
-				executeScript(devnull, cmd)
+					if err := executeScript(devnull, cmd); err != nil {
+						Fatal(err)
+					}
 				}
 				if err := input.Err(); err == io.EOF {
 					break
@@ -52,7 +55,24 @@ func main() {
 			if err != nil {
 				Fatal("parse error: %v\n", err)
 			}
-		executeScript(devnull, script)
+			if err := executeScript(devnull, script); err != nil {
+				Fatal(err)
+			}
+		}
+	} else {
+		for _, scriptpath := range os.Args[1:] {
+			f, err := os.Open(scriptpath)
+			if err != nil {
+				Fatal(err)
+			}
+			script, err := dockerscript.Parse(f)
+			if err != nil {
+				Fatal("parse error: %v\n", err)
+			}
+			if err := executeScript(devnull, script); err != nil {
+				Fatal(err)
+			}
+		}
 	}
 }
 

beam/examples/beamsh/helloworld.ds

@@ -0,0 +1,8 @@
+#!/usr/bin/env beamsh
+
+print {
+	trace {
+		emit hello
+		emit world
+	}
+}