dynamic host volumes: add -type flag to volume init (#24667)

Adds a `-type` flag to the `volume init` command that generates an example
volume specification with only those fields relevant to dynamic host
volumes. This changeset also moves the string literals into uses of `go:embed`

Ref: https://github.com/hashicorp/nomad/pull/24479

command/asset/asset.go

@@ -22,3 +22,15 @@ var NodePoolSpec []byte
 
 //go:embed pool.nomad.json
 var NodePoolSpecJSON []byte
+
+//go:embed volume.csi.hcl
+var CSIVolumeSpecHCL []byte
+
+//go:embed volume.csi.json
+var CSIVolumeSpecJSON []byte
+
+//go:embed volume.host.hcl
+var HostVolumeSpecHCL []byte
+
+//go:embed volume.host.json
+var HostVolumeSpecJSON []byte

command/asset/volume.csi.hcl

@@ -0,0 +1,70 @@
+id        = "ebs_prod_db1"
+namespace = "default"
+name      = "database"
+type      = "csi"
+plugin_id = "plugin_id"
+
+# For 'nomad volume register', provide the external ID from the storage
+# provider. This field should be omitted when creating a volume with
+# 'nomad volume create'
+external_id = "vol-23452345"
+
+# For 'nomad volume create', specify a snapshot ID or volume to clone. You can
+# specify only one of these two fields.
+snapshot_id = "snap-12345"
+# clone_id    = "vol-abcdef"
+
+# Optional: for 'nomad volume create', specify a maximum and minimum capacity.
+# Registering an existing volume will record but ignore these fields.
+capacity_min = "10GiB"
+capacity_max = "20G"
+
+# Required (at least one): for 'nomad volume create', specify one or more
+# capabilities to validate. Registering an existing volume will record but
+# ignore these fields.
+capability {
+  access_mode     = "single-node-writer"
+  attachment_mode = "file-system"
+}
+
+capability {
+  access_mode     = "single-node-reader"
+  attachment_mode = "block-device"
+}
+
+# Optional: for 'nomad volume create', specify mount options to validate for
+# 'attachment_mode = "file-system". Registering an existing volume will record
+# but ignore these fields.
+mount_options {
+  fs_type     = "ext4"
+  mount_flags = ["ro"]
+}
+
+# Optional: specify one or more locations where the volume must be accessible
+# from. Refer to the plugin documentation for what segment values are supported.
+topology_request {
+  preferred {
+    topology { segments { rack = "R1" } }
+  }
+  required {
+    topology { segments { rack = "R1" } }
+    topology { segments { rack = "R2", zone = "us-east-1a" } }
+  }
+}
+
+# Optional: provide any secrets specified by the plugin.
+secrets {
+  example_secret = "xyzzy"
+}
+
+# Optional: provide a map of keys to string values expected by the plugin.
+parameters {
+  skuname = "Premium_LRS"
+}
+
+# Optional: for 'nomad volume register', provide a map of keys to string
+# values expected by the plugin. This field will populated automatically by
+# 'nomad volume create'.
+context {
+  endpoint = "http://192.168.1.101:9425"
+}

command/asset/volume.csi.json

@@ -0,0 +1,72 @@
+{
+  "id": "ebs_prod_db1",
+  "namespace": "default",
+  "name": "database",
+  "type": "csi",
+  "plugin_id": "plugin_id",
+  "external_id": "vol-23452345",
+  "snapshot_id": "snap-12345",
+  "capacity_min": "10GiB",
+  "capacity_max": "20G",
+  "capability": [
+    {
+      "access_mode": "single-node-writer",
+      "attachment_mode": "file-system"
+    },
+    {
+      "access_mode": "single-node-reader",
+      "attachment_mode": "block-device"
+    }
+  ],
+  "context": [
+    {
+      "endpoint": "http://192.168.1.101:9425"
+    }
+  ],
+  "mount_options": [
+    {
+      "fs_type": "ext4",
+      "mount_flags": [
+        "ro"
+      ]
+    }
+  ],
+  "topology_request": {
+    "preferred": [
+      {
+        "topology": {
+          "segments": {
+            "rack": "R1"
+          }
+        }
+      }
+    ],
+    "required": [
+      {
+        "topology": {
+          "segments": {
+            "rack": "R1"
+          }
+        }
+      },
+      {
+        "topology": {
+          "segments": {
+            "rack": "R2",
+            "zone": "us-east-1a"
+          }
+        }
+      }
+    ]
+  },
+  "parameters": [
+    {
+      "skuname": "Premium_LRS"
+    }
+  ],
+  "secrets": [
+    {
+      "example_secret": "xyzzy"
+    }
+  ]
+}

command/asset/volume.host.hcl

@@ -0,0 +1,28 @@
+id        = "disk_prod_db1"
+namespace = "default"
+name      = "database"
+type      = "host"
+plugin_id = "plugin_id"
+
+# Optional: for 'nomad volume create', specify a maximum and minimum capacity.
+# Registering an existing volume will record but ignore these fields.
+capacity_min = "10GiB"
+capacity_max = "20G"
+
+# Required (at least one): for 'nomad volume create', specify one or more
+# capabilities to validate. Registering an existing volume will record but
+# ignore these fields.
+capability {
+  access_mode     = "single-node-writer"
+  attachment_mode = "file-system"
+}
+
+capability {
+  access_mode     = "single-node-reader"
+  attachment_mode = "block-device"
+}
+
+# Optional: provide a map of keys to string values expected by the plugin.
+parameters {
+  skuname = "Premium_LRS"
+}

command/asset/volume.host.json

@@ -0,0 +1,24 @@
+{
+  "id": "disk_prod_db1",
+  "namespace": "default",
+  "name": "database",
+  "type": "host",
+  "plugin_id": "plugin_id",
+  "capacity_min": "10GiB",
+  "capacity_max": "20G",
+  "capability": [
+    {
+      "access_mode": "single-node-writer",
+      "attachment_mode": "file-system"
+    },
+    {
+      "access_mode": "single-node-reader",
+      "attachment_mode": "block-device"
+    }
+  ],
+  "parameters": [
+    {
+      "skuname": "Premium_LRS"
+    }
+  ]
+}

command/volume_init.go

@@ -8,17 +8,18 @@ import (
 	"os"
 	"strings"
 
+	"github.com/hashicorp/nomad/command/asset"
 	"github.com/posener/complete"
 )
 
 const (
-	// DefaultHclVolumeInitName is the default name we use when initializing
+	// defaultHclVolumeInitName is the default name we use when initializing
 	// the example volume file in HCL format
-	DefaultHclVolumeInitName = "volume.hcl"
+	defaultHclVolumeInitName = "volume.hcl"
 
 	// DefaultHclVolumeInitName is the default name we use when initializing
 	// the example volume file in JSON format
-	DefaultJsonVolumeInitName = "volume.json"
+	defaultJsonVolumeInitName = "volume.json"
 )
 
 // VolumeInitCommand generates a new volume spec that you can customize to
@@ -39,6 +40,11 @@ Init Options:
 
   -json
     Create an example JSON volume specification.
+
+  -type
+    Create an example for a specific type of volume (one of "csi" or "host",
+    defaults to "csi").
+
 `
 	return strings.TrimSpace(helpText)
 }
@@ -50,6 +56,7 @@ func (c *VolumeInitCommand) Synopsis() string {
 func (c *VolumeInitCommand) AutocompleteFlags() complete.Flags {
 	return complete.Flags{
 		"-json": complete.PredictNothing,
+		"-type": complete.PredictSet("host", "csi"),
 	}
 }
 
@@ -61,9 +68,11 @@ func (c *VolumeInitCommand) Name() string { return "volume init" }
 
 func (c *VolumeInitCommand) Run(args []string) int {
 	var jsonOutput bool
+	var volType string
 	flags := c.Meta.FlagSet(c.Name(), FlagSetClient)
 	flags.Usage = func() { c.Ui.Output(c.Help()) }
 	flags.BoolVar(&jsonOutput, "json", false, "")
+	flags.StringVar(&volType, "type", "csi", "type of volume")
 
 	if err := flags.Parse(args); err != nil {
 		return 1
@@ -77,11 +86,17 @@ func (c *VolumeInitCommand) Run(args []string) int {
 		return 1
 	}
 
-	fileName := DefaultHclVolumeInitName
+	fileName := defaultHclVolumeInitName
-	fileContent := defaultHclVolumeSpec
+	fileContent := asset.CSIVolumeSpecHCL
-	if jsonOutput {
+
-		fileName = DefaultJsonVolumeInitName
+	if volType == "host" && !jsonOutput {
-		fileContent = defaultJsonVolumeSpec
+		fileContent = asset.HostVolumeSpecHCL
+	} else if volType == "host" && jsonOutput {
+		fileName = defaultJsonVolumeInitName
+		fileContent = asset.HostVolumeSpecJSON
+	} else if jsonOutput {
+		fileName = defaultJsonVolumeInitName
+		fileContent = asset.CSIVolumeSpecJSON
 	}
 	if len(args) == 1 {
 		fileName = args[0]
@@ -99,7 +114,7 @@ func (c *VolumeInitCommand) Run(args []string) int {
 	}
 
 	// Write out the example
-	err = os.WriteFile(fileName, []byte(fileContent), 0660)
+	err = os.WriteFile(fileName, fileContent, 0660)
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to write %q: %v", fileName, err))
 		return 1
@@ -109,151 +124,3 @@ func (c *VolumeInitCommand) Run(args []string) int {
 	c.Ui.Output(fmt.Sprintf("Example volume specification written to %s", fileName))
 	return 0
 }
-
-var defaultHclVolumeSpec = strings.TrimSpace(`
-id        = "ebs_prod_db1"
-namespace = "default"
-name      = "database"
-type      = "csi"
-plugin_id = "plugin_id"
-
-# For 'nomad volume register', provide the external ID from the storage
-# provider. This field should be omitted when creating a volume with
-# 'nomad volume create'
-external_id = "vol-23452345"
-
-# For 'nomad volume create', specify a snapshot ID or volume to clone. You can
-# specify only one of these two fields.
-snapshot_id = "snap-12345"
-# clone_id    = "vol-abcdef"
-
-# Optional: for 'nomad volume create', specify a maximum and minimum capacity.
-# Registering an existing volume will record but ignore these fields.
-capacity_min = "10GiB"
-capacity_max = "20G"
-
-# Required (at least one): for 'nomad volume create', specify one or more
-# capabilities to validate. Registering an existing volume will record but
-# ignore these fields.
-capability {
-  access_mode     = "single-node-writer"
-  attachment_mode = "file-system"
-}
-
-capability {
-  access_mode     = "single-node-reader"
-  attachment_mode = "block-device"
-}
-
-# Optional: for 'nomad volume create', specify mount options to validate for
-# 'attachment_mode = "file-system". Registering an existing volume will record
-# but ignore these fields.
-mount_options {
-  fs_type     = "ext4"
-  mount_flags = ["ro"]
-}
-
-# Optional: specify one or more locations where the volume must be accessible
-# from. Refer to the plugin documentation for what segment values are supported.
-topology_request {
-  preferred {
-    topology { segments { rack = "R1" } }
-  }
-  required {
-    topology { segments { rack = "R1" } }
-    topology { segments { rack = "R2", zone = "us-east-1a" } }
-  }
-}
-
-# Optional: provide any secrets specified by the plugin.
-secrets {
-  example_secret = "xyzzy"
-}
-
-# Optional: provide a map of keys to string values expected by the plugin.
-parameters {
-  skuname = "Premium_LRS"
-}
-
-# Optional: for 'nomad volume register', provide a map of keys to string
-# values expected by the plugin. This field will populated automatically by
-# 'nomad volume create'.
-context {
-  endpoint = "http://192.168.1.101:9425"
-}
-`)
-
-var defaultJsonVolumeSpec = strings.TrimSpace(`
-{
-  "id": "ebs_prod_db1",
-  "namespace": "default",
-  "name": "database",
-  "type": "csi",
-  "plugin_id": "plugin_id",
-  "external_id": "vol-23452345",
-  "snapshot_id": "snap-12345",
-  "capacity_min": "10GiB",
-  "capacity_max": "20G",
-  "capability": [
-    {
-      "access_mode": "single-node-writer",
-      "attachment_mode": "file-system"
-    },
-    {
-      "access_mode": "single-node-reader",
-      "attachment_mode": "block-device"
-    }
-  ],
-  "context": [
-    {
-      "endpoint": "http://192.168.1.101:9425"
-    }
-  ],
-  "mount_options": [
-    {
-      "fs_type": "ext4",
-      "mount_flags": [
-        "ro"
-      ]
-    }
-  ],
-  "topology_request": {
-    "preferred": [
-      {
-        "topology": {
-          "segments": {
-            "rack": "R1"
-          }
-        }
-      }
-    ],
-    "required": [
-      {
-        "topology": {
-          "segments": {
-            "rack": "R1"
-          }
-        }
-      },
-      {
-        "topology": {
-          "segments": {
-            "rack": "R2",
-            "zone": "us-east-1a"
-          }
-        }
-      }
-    ]
-  },
-  "parameters": [
-    {
-      "skuname": "Premium_LRS"
-    }
-  ],
-  "secrets": [
-    {
-      "example_secret": "xyzzy"
-    }
-  ]
-}
-`)