cmd: add scale and scaling-events commands to job cmd.

This adds the ability to scale Nomad jobs and view scaling events
via the CLI.

command/commands.go

@@ -357,6 +357,16 @@ func Commands(metaPtr *Meta, agentUi cli.Ui) map[string]cli.CommandFactory {
 				Meta: meta,
 			}, nil
 		},
+		"job scale": func() (cli.Command, error) {
+			return &JobScaleCommand{
+				Meta: meta,
+			}, nil
+		},
+		"job scaling-events": func() (cli.Command, error) {
+			return &JobScalingEventsCommand{
+				Meta: meta,
+			}, nil
+		},
 		"job status": func() (cli.Command, error) {
 			return &JobStatusCommand{
 				Meta: meta,

command/job_scale.go

@@ -0,0 +1,185 @@
+package command
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/hashicorp/nomad/api"
+	"github.com/mitchellh/cli"
+	"github.com/posener/complete"
+)
+
+// Ensure JobScaleCommand satisfies the cli.Command interface.
+var _ cli.Command = &JobScaleCommand{}
+
+// JobScaleCommand implements cli.Command.
+type JobScaleCommand struct {
+	Meta
+}
+
+// Help satisfies the cli.Command Help function.
+func (j *JobScaleCommand) Help() string {
+	helpText := `
+Usage: nomad job scale [options] <args>
+
+  Perform a scaling action by altering the count within a job group.
+
+  Upon successful job submission, this command will immediately
+  enter an interactive monitor. This is useful to watch Nomad's
+  internals make scheduling decisions and place the submitted work
+  onto nodes. The monitor will end once job placement is done. It
+  is safe to exit the monitor early using ctrl+c.
+
+General Options:
+
+  ` + generalOptionsUsage() + `
+
+Scale Options:
+
+  -detach
+    Return immediately instead of entering monitor mode. After job scaling,
+    the evaluation ID will be printed to the screen, which can be used to
+    examine the evaluation using the eval-status command.
+
+  -verbose
+    Display full information.
+`
+	return strings.TrimSpace(helpText)
+}
+
+// Synopsis satisfies the cli.Command Synopsis function.
+func (j *JobScaleCommand) Synopsis() string {
+	return "Change the count of a Nomad job group"
+}
+
+func (j *JobScaleCommand) AutocompleteFlags() complete.Flags {
+	return mergeAutocompleteFlags(j.Meta.AutocompleteFlags(FlagSetClient),
+		complete.Flags{
+			"-detach":  complete.PredictNothing,
+			"-verbose": complete.PredictNothing,
+		})
+}
+
+// Name returns the name of this command.
+func (j *JobScaleCommand) Name() string { return "job scale" }
+
+// Run satisfies the cli.Command Run function.
+func (j *JobScaleCommand) Run(args []string) int {
+	var detach, verbose bool
+
+	flags := j.Meta.FlagSet(j.Name(), FlagSetClient)
+	flags.Usage = func() { j.Ui.Output(j.Help()) }
+	flags.BoolVar(&detach, "detach", false, "")
+	flags.BoolVar(&verbose, "verbose", false, "")
+	if err := flags.Parse(args); err != nil {
+		return 1
+	}
+
+	var jobString, countString, groupString string
+	args = flags.Args()
+
+	// It is possible to specify either 2 or 3 arguments. Check and assign the
+	// args so they can be validate later on.
+	if numArgs := len(args); numArgs < 2 || numArgs > 3 {
+		j.Ui.Error("Command requires at least two arguments and no more than three")
+		return 1
+	} else if numArgs == 3 {
+		groupString = args[1]
+		countString = args[2]
+	} else {
+		countString = args[1]
+	}
+	jobString = args[0]
+
+	// Convert the count string arg to an int as required by the API.
+	count, err := strconv.Atoi(countString)
+	if err != nil {
+		j.Ui.Error(fmt.Sprintf("Failed to convert count string to int: %s", err))
+		return 1
+	}
+
+	// Get the HTTP client.
+	client, err := j.Meta.Client()
+	if err != nil {
+		j.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
+		return 1
+	}
+
+	// Detail the job so we can perform addition checks before submitting the
+	// scaling request.
+	job, _, err := client.Jobs().Info(jobString, nil)
+	if err != nil {
+		j.Ui.Error(fmt.Sprintf("Error querying job: %v", err))
+		return 1
+	}
+
+	if err := j.performGroupCheck(job.TaskGroups, &groupString); err != nil {
+		j.Ui.Error(err.Error())
+		return 1
+	}
+
+	// This is our default message added to scaling submissions.
+	msg := "submitted using the Nomad CLI"
+
+	// Perform the scaling action.
+	resp, _, err := client.Jobs().Scale(jobString, groupString, &count, msg, false, nil, nil)
+	if err != nil {
+		j.Ui.Error(fmt.Sprintf("Error submitting scaling request: %s", err))
+		return 1
+	}
+
+	// Print any warnings if we have some.
+	if resp.Warnings != "" {
+		j.Ui.Output(
+			j.Colorize().Color(fmt.Sprintf("[bold][yellow]Job Warnings:\n%s[reset]\n", resp.Warnings)))
+	}
+
+	// If we are to detach, log the evaluation ID and exit.
+	if detach {
+		j.Ui.Output("Evaluation ID: " + resp.EvalID)
+		return 0
+	}
+
+	// Truncate the ID unless full length is requested.
+	length := shortId
+	if verbose {
+		length = fullId
+	}
+
+	// Create and monitor the evaluation.
+	mon := newMonitor(j.Ui, client, length)
+	return mon.monitor(resp.EvalID, false)
+}
+
+// performGroupCheck performs logic to ensure the user specified the correct
+// group argument.
+func (j *JobScaleCommand) performGroupCheck(groups []*api.TaskGroup, group *string) error {
+
+	// If the job contains multiple groups and the user did not supply a task
+	// group, return an error.
+	if len(groups) > 1 && *group == "" {
+		return errors.New("Group name required")
+	}
+
+	// If the job has a single task group, and the user did not supply a task
+	// group, it is assumed we scale the only group in the job.
+	if len(groups) == 1 && *group == "" {
+		*group = *groups[0].Name
+		return nil
+	}
+
+	// Iterate the groups within the job and ensure the user specified exists.
+	var found bool
+	for _, tg := range groups {
+		if *tg.Name == *group {
+			found = true
+			break
+		}
+	}
+	if !found {
+		return fmt.Errorf("Group %v not found within job", *group)
+	}
+	return nil
+}

command/job_scale_test.go

@@ -0,0 +1,123 @@
+package command
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/nomad/api"
+	"github.com/hashicorp/nomad/helper"
+	"github.com/hashicorp/nomad/testutil"
+	"github.com/mitchellh/cli"
+)
+
+func TestJobScaleCommand_SingleGroup(t *testing.T) {
+	t.Parallel()
+	srv, client, url := testServer(t, true, nil)
+	defer srv.Shutdown()
+	testutil.WaitForResult(func() (bool, error) {
+		nodes, _, err := client.Nodes().List(nil)
+		if err != nil {
+			return false, err
+		}
+		if len(nodes) == 0 {
+			return false, fmt.Errorf("missing node")
+		}
+		if _, ok := nodes[0].Drivers["mock_driver"]; !ok {
+			return false, fmt.Errorf("mock_driver not ready")
+		}
+		return true, nil
+	}, func(err error) {
+		t.Fatalf("err: %s", err)
+	})
+
+	ui := cli.NewMockUi()
+	cmd := &JobScaleCommand{Meta: Meta{Ui: ui}}
+
+	// Register a test job and ensure it is running before moving on.
+	resp, _, err := client.Jobs().Register(testJob("scale_cmd_single_group"), nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if code := waitForSuccess(ui, client, fullId, t, resp.EvalID); code != 0 {
+		t.Fatalf("expected waitForSuccess exit code 0, got: %d", code)
+	}
+
+	// Perform the scaling action.
+	if code := cmd.Run([]string{"-address=" + url, "-detach", "scale_cmd_single_group", "2"}); code != 0 {
+		t.Fatalf("expected cmd run exit code 0, got: %d", code)
+	}
+	if out := ui.OutputWriter.String(); !strings.Contains(out, "Evaluation ID:") {
+		t.Fatalf("Expected Evaluation ID within output: %v", out)
+	}
+}
+
+func TestJobScaleCommand_MultiGroup(t *testing.T) {
+	t.Parallel()
+	srv, client, url := testServer(t, true, nil)
+	defer srv.Shutdown()
+	testutil.WaitForResult(func() (bool, error) {
+		nodes, _, err := client.Nodes().List(nil)
+		if err != nil {
+			return false, err
+		}
+		if len(nodes) == 0 {
+			return false, fmt.Errorf("missing node")
+		}
+		if _, ok := nodes[0].Drivers["mock_driver"]; !ok {
+			return false, fmt.Errorf("mock_driver not ready")
+		}
+		return true, nil
+	}, func(err error) {
+		t.Fatalf("err: %s", err)
+	})
+
+	ui := cli.NewMockUi()
+	cmd := &JobScaleCommand{Meta: Meta{Ui: ui}}
+
+	// Create a job with two task groups.
+	job := testJob("scale_cmd_multi_group")
+	task := api.NewTask("task2", "mock_driver").
+		SetConfig("kill_after", "1s").
+		SetConfig("run_for", "5s").
+		SetConfig("exit_code", 0).
+		Require(&api.Resources{
+			MemoryMB: helper.IntToPtr(256),
+			CPU:      helper.IntToPtr(100),
+		}).
+		SetLogConfig(&api.LogConfig{
+			MaxFiles:      helper.IntToPtr(1),
+			MaxFileSizeMB: helper.IntToPtr(2),
+		})
+	group2 := api.NewTaskGroup("group2", 1).
+		AddTask(task).
+		RequireDisk(&api.EphemeralDisk{
+			SizeMB: helper.IntToPtr(20),
+		})
+	job.AddTaskGroup(group2)
+
+	// Register a test job and ensure it is running before moving on.
+	resp, _, err := client.Jobs().Register(job, nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if code := waitForSuccess(ui, client, fullId, t, resp.EvalID); code != 0 {
+		t.Fatalf("expected waitForSuccess exit code 0, got: %d", code)
+	}
+
+	// Attempt to scale without specifying the task group which should fail.
+	if code := cmd.Run([]string{"-address=" + url, "-detach", "scale_cmd_multi_group", "2"}); code != 1 {
+		t.Fatalf("expected cmd run exit code 1, got: %d", code)
+	}
+	if out := ui.ErrorWriter.String(); !strings.Contains(out, "Group name required") {
+		t.Fatalf("unexpected error message: %v", out)
+	}
+
+	// Specify the target group which should be successful.
+	if code := cmd.Run([]string{"-address=" + url, "-detach", "scale_cmd_multi_group", "group1", "2"}); code != 0 {
+		t.Fatalf("expected cmd run exit code 0, got: %d", code)
+	}
+	if out := ui.OutputWriter.String(); !strings.Contains(out, "Evaluation ID:") {
+		t.Fatalf("Expected Evaluation ID within output: %v", out)
+	}
+}