Support nomad plan to take jobfile from stdin

command/plan.go

@@ -2,6 +2,8 @@ package command
 
 import (
 	"fmt"
+	"io"
+	"os"
 	"sort"
 	"strings"
 	"time"
@@ -26,6 +28,9 @@ potentially invalid.`
 type PlanCommand struct {
 	Meta
 	color *colorstring.Colorize
+
+	// The fields below can be overwritten for tests
+	testStdin io.Reader
 }
 
 func (c *PlanCommand) Help() string {
@@ -37,6 +42,9 @@ Usage: nomad plan [options] <file>
   changes to the cluster but gives insight into whether the job could be run
   successfully and how it would affect existing allocations.
 
+  If the supplied path is "-", the jobfile is read from stdin. Otherwise
+  it is read from the file at the supplied path.
+
   A job modify index is returned with the plan. This value can be used when
   submitting the job using "nomad run -check-index", which will check that the job
   was not modified between the plan and run command before invoking the
@@ -86,12 +94,33 @@ func (c *PlanCommand) Run(args []string) int {
 		c.Ui.Error(c.Help())
 		return 1
 	}
-	file := args[0]
 
-	// Parse the job file
-	job, err := jobspec.ParseFile(file)
+	// Read the Jobfile
+	path := args[0]
+
+	var f io.Reader
+	switch path {
+	case "-":
+		if c.testStdin != nil {
+			f = c.testStdin
+		} else {
+			f = os.Stdin
+		}
+		path = "stdin"
+	default:
+		file, err := os.Open(path)
+		defer file.Close()
+		if err != nil {
+			c.Ui.Error(fmt.Sprintf("Error opening file %q: %v", path, err))
+			return 1
+		}
+		f = file
+	}
+
+	// Parse the JobFile
+	job, err := jobspec.Parse(f)
 	if err != nil {
-		c.Ui.Error(fmt.Sprintf("Error parsing job file %s: %s", file, err))
+		c.Ui.Error(fmt.Sprintf("Error parsing job file %s: %v", path, err))
 		return 1
 	}
 
@@ -142,7 +171,7 @@ func (c *PlanCommand) Run(args []string) int {
 	c.Ui.Output("")
 
 	// Print the job index info
-	c.Ui.Output(c.Colorize().Color(formatJobModifyIndex(resp.JobModifyIndex, file)))
+	c.Ui.Output(c.Colorize().Color(formatJobModifyIndex(resp.JobModifyIndex, path)))
 	return 0
 }
 

command/plan_test.go

@@ -30,7 +30,7 @@ func TestPlanCommand_Fails(t *testing.T) {
 	if code := cmd.Run([]string{"/unicorns/leprechauns"}); code != 1 {
 		t.Fatalf("expect exit 1, got: %d", code)
 	}
-	if out := ui.ErrorWriter.String(); !strings.Contains(out, "Error parsing") {
+	if out := ui.ErrorWriter.String(); !strings.Contains(out, "Error opening") {
 		t.Fatalf("expect parsing error, got: %s", out)
 	}
 	ui.ErrorWriter.Reset()
@@ -101,3 +101,46 @@ job "job1" {
 		t.Fatalf("expected failed query error, got: %s", out)
 	}
 }
+
+func TestPlanCommand_From_STDIN(t *testing.T) {
+	stdinR, stdinW, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	ui := new(cli.MockUi)
+	cmd := &PlanCommand{
+		Meta:      Meta{Ui: ui},
+		testStdin: stdinR,
+	}
+
+	go func() {
+		stdinW.WriteString(`
+job "job1" {
+  type = "service"
+  datacenters = [ "dc1" ]
+  group "group1" {
+                count = 1
+                task "task1" {
+                        driver = "exec"
+                        resources = {
+                                cpu = 1000
+                                disk = 150
+                                memory = 512
+                        }
+                }
+        }
+}`)
+		stdinW.Close()
+	}()
+
+	args := []string{"-"}
+	if code := cmd.Run(args); code != 1 {
+		t.Fatalf("expected exit code 1, got %d: %q", code, ui.ErrorWriter.String())
+	}
+
+	if out := ui.ErrorWriter.String(); !strings.Contains(out, "connection refused") {
+		t.Fatalf("expected runtime error, got: %s", out)
+	}
+	ui.ErrorWriter.Reset()
+}