nomad run -output emits the JSON representation of the job

command/run.go

@@ -3,6 +3,7 @@ package command
 import (
 	"bytes"
 	"encoding/gob"
+	"encoding/json"
 	"fmt"
 	"strings"
 	"time"
@@ -50,6 +51,10 @@ Run Options:
 
   -verbose
     Display full information.
+
+  -output
+    Output the JSON that would be submitted to the HTTP API without submitting
+    the job.
 `
 	return strings.TrimSpace(helpText)
 }
@@ -59,12 +64,13 @@ func (c *RunCommand) Synopsis() string {
 }
 
 func (c *RunCommand) Run(args []string) int {
-	var detach, verbose bool
+	var detach, verbose, output bool
 
 	flags := c.Meta.FlagSet("run", FlagSetClient)
 	flags.Usage = func() { c.Ui.Output(c.Help()) }
 	flags.BoolVar(&detach, "detach", false, "")
 	flags.BoolVar(&verbose, "verbose", false, "")
+	flags.BoolVar(&output, "output", false, "")
 
 	if err := flags.Parse(args); err != nil {
 		return 1
@@ -110,6 +116,17 @@ func (c *RunCommand) Run(args []string) int {
 		return 1
 	}
 
+	if output {
+		buf, err := json.MarshalIndent(apiJob, "", "    ")
+		if err != nil {
+			c.Ui.Error(fmt.Sprintf("Error converting job: %s", err))
+			return 1
+		}
+
+		c.Ui.Output(string(buf))
+		return 0
+	}
+
 	// Get the HTTP client
 	client, err := c.Meta.Client()
 	if err != nil {

command/run_test.go

@@ -13,6 +13,42 @@ func TestRunCommand_Implements(t *testing.T) {
 	var _ cli.Command = &RunCommand{}
 }
 
+func TestRunCommand_Output_Json(t *testing.T) {
+	ui := new(cli.MockUi)
+	cmd := &RunCommand{Meta: Meta{Ui: ui}}
+
+	fh, err := ioutil.TempFile("", "nomad")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer os.Remove(fh.Name())
+	_, err = fh.WriteString(`
+job "job1" {
+	type = "service"
+	datacenters = [ "dc1" ]
+	group "group1" {
+		count = 1
+		task "task1" {
+			driver = "exec"
+			resources = {
+				cpu = 1000
+				disk = 150
+				memory = 512
+			}
+		}
+	}
+}`)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if code := cmd.Run([]string{"-output", fh.Name()}); code != 0 {
+		t.Fatalf("expected exit code 0, got: %d", code)
+	}
+	if out := ui.OutputWriter.String(); !strings.Contains(out, `"Region": "global",`) {
+		t.Fatalf("Expected JSON output: %v", out)
+	}
+}
+
 func TestRunCommand_Fails(t *testing.T) {
 	ui := new(cli.MockUi)
 	cmd := &RunCommand{Meta: Meta{Ui: ui}}

website/source/docs/commands/run.html.md.erb

@@ -42,6 +42,9 @@ client connection issues or internal errors, are indicated by exit code 1.
   will be output, which can be used to call the monitor later using the
   [eval-monitor](/docs/commands/eval-monitor.html) command.
 
+* `-output`: Output the JSON that would be submitted to the HTTP API without
+  submitting the job.
+
 ## Status Options
 
 * `-verbose`: Show full information.

website/source/docs/jobspec/json.html.md

@@ -9,7 +9,9 @@ description: |-
 # Job Specification
 
 Jobs can be specified either in [HCL](https://github.com/hashicorp/hcl) or JSON.
-This guide covers the json syntax for submitting jobs to Nomad.
+This guide covers the json syntax for submitting jobs to Nomad. A useful command
+for generating valid JSON versions of HCL jobs is `nomad run -output <job.nomad>`
+which will emit a JSON version of the job.
 
 ## JSON Syntax