csi: volume init command

Create a convenience command for generating example CSI volume specifications,
similar to the existing `nomad job init` or `nomad quota init` commands.

.gitignore

@@ -55,7 +55,11 @@ ui/dist/
 website/.bundle
 website/vendor
 
+# init outputs
 example.nomad
+spec.hcl
+volume.hcl
+
 nomad_linux_amd64
 nomad_darwin_amd64
 TODO.md

command/commands.go

@@ -796,6 +796,11 @@ func Commands(metaPtr *Meta, agentUi cli.Ui) map[string]cli.CommandFactory {
 				Meta: meta,
 			}, nil
 		},
+		"volume init": func() (cli.Command, error) {
+			return &VolumeInitCommand{
+				Meta: meta,
+			}, nil
+		},
 		"volume status": func() (cli.Command, error) {
 			return &VolumeStatusCommand{
 				Meta: meta,

command/volume_init.go

@@ -0,0 +1,154 @@
+package command
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/posener/complete"
+)
+
+const (
+	// DefaultHclVolumeInitName is the default name we use when initializing
+	// the example volume file in HCL format
+	DefaultHclVolumeInitName = "volume.hcl"
+
+	// DefaultHclVolumeInitName is the default name we use when initializing
+	// the example volume file in JSON format
+	DefaultJsonVolumeInitName = "volume.json"
+)
+
+// VolumeInitCommand generates a new volume spec that you can customize to
+// your liking, like vagrant init
+type VolumeInitCommand struct {
+	Meta
+}
+
+func (c *VolumeInitCommand) Help() string {
+	helpText := `
+Usage: nomad volume init
+
+  Creates an example volume specification file that can be used as a starting
+  point to customize further.
+
+Init Options:
+
+  -json
+    Create an example JSON volume specification.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *VolumeInitCommand) Synopsis() string {
+	return "Create an example volume specification file"
+}
+
+func (c *VolumeInitCommand) AutocompleteFlags() complete.Flags {
+	return complete.Flags{
+		"-json": complete.PredictNothing,
+	}
+}
+
+func (c *VolumeInitCommand) AutocompleteArgs() complete.Predictor {
+	return complete.PredictNothing
+}
+
+func (c *VolumeInitCommand) Name() string { return "volume init" }
+
+func (c *VolumeInitCommand) Run(args []string) int {
+	var jsonOutput bool
+	flags := c.Meta.FlagSet(c.Name(), FlagSetClient)
+	flags.Usage = func() { c.Ui.Output(c.Help()) }
+	flags.BoolVar(&jsonOutput, "json", false, "")
+
+	if err := flags.Parse(args); err != nil {
+		return 1
+	}
+
+	// Check that we get no arguments
+	args = flags.Args()
+	if l := len(args); l != 0 {
+		c.Ui.Error("This command takes no arguments")
+		c.Ui.Error(commandErrorText(c))
+		return 1
+	}
+
+	fileName := DefaultHclVolumeInitName
+	fileContent := defaultHclVolumeSpec
+	if jsonOutput {
+		fileName = DefaultJsonVolumeInitName
+		fileContent = defaultJsonVolumeSpec
+	}
+
+	// Check if the file already exists
+	_, err := os.Stat(fileName)
+	if err != nil && !os.IsNotExist(err) {
+		c.Ui.Error(fmt.Sprintf("Failed to stat %q: %v", fileName, err))
+		return 1
+	}
+	if !os.IsNotExist(err) {
+		c.Ui.Error(fmt.Sprintf("Volume specification %q already exists", fileName))
+		return 1
+	}
+
+	// Write out the example
+	err = ioutil.WriteFile(fileName, []byte(fileContent), 0660)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to write %q: %v", fileName, err))
+		return 1
+	}
+
+	// Success
+	c.Ui.Output(fmt.Sprintf("Example volume specification written to %s", fileName))
+	return 0
+}
+
+var defaultHclVolumeSpec = strings.TrimSpace(`
+id              = "ebs_prod_db1"
+name            = "database"
+type            = "csi"
+external_id     = "vol-23452345"
+access_mode     = "single-node-writer"
+attachment_mode = "file-system"
+
+mount_options {
+  fs_type     = "ext4"
+  mount_flags = ["ro"]
+}
+secrets {
+  example_secret = "xyzzy"
+}
+parameters {
+  skuname = "Premium_LRS"
+}
+context {
+  endpoint = "http://192.168.1.101:9425"
+}
+`)
+
+var defaultJsonVolumeSpec = strings.TrimSpace(`
+{
+  "id": "ebs_prod_db1",
+  "name": "database",
+  "type": "csi",
+  "external_id": "vol-23452345",
+  "access_mode": "single-node-writer",
+  "attachment_mode": "file-system",
+  "mount_options": {
+    "fs_type": "ext4",
+    "mount_flags": [
+      "ro"
+    ]
+  },
+  "secrets": {
+    "example_secret": "xyzzy"
+  },
+  "parameters": {
+    "skuname": "Premium_LRS"
+  },
+  "context": {
+    "endpoint": "http://192.168.1.101:9425"
+  }
+}
+`)

website/content/docs/commands/volume/index.mdx

@@ -19,10 +19,12 @@ subcommands are available:
 
 - [`volume deregister`][deregister] - Deregister a volume.
 - [`volume detach`][detach] - Detach a volume.
+- [`volume init`][init] - Create an example volume specification file
 - [`volume register`][register] - Register a volume.
 - [`volume status`][status] - Display status information about a volume
 
 [deregister]: /docs/commands/volume/deregister 'Deregister a volume'
 [detach]: /docs/commands/volume/detach 'Detach a volume'
+[init]: /docs/commands/volume/init 'Create an example volume specification file'
 [register]: /docs/commands/volume/register 'Register a volume'
 [status]: /docs/commands/volume/status 'Display status information about a volume'

website/content/docs/commands/volume/init.mdx

@@ -0,0 +1,31 @@
+---
+layout: docs
+page_title: 'Commands: volume init'
+sidebar_title: init
+description: |
+  Generate an example volume specification.
+---
+
+# Command: volume init
+
+The `volume init` command is used to create an example volume specification
+file that can be used as a starting point to customize further.
+
+## Usage
+
+```plaintext
+nomad volume init
+```
+
+## Init Options
+
+- `-json`: Create an example JSON volume specification.
+
+## Examples
+
+Create an example volume specification:
+
+```shell-session
+$ nomad volume init
+Example volume specification written to volume.hcl
+```

website/data/docs-navigation.js

@@ -177,7 +177,7 @@ export default [
       'version',
       {
         category: 'volume',
-        content: ['deregister', 'detach', 'status', 'register'],
+        content: ['deregister', 'detach', 'init', 'register', 'status'],
       },
     ],
   },