integrated cloud-init support (fix #10)

Author: mxschmitt

README.md

@@ -41,15 +41,16 @@ $ cp docker-machine-driver-hetzner /usr/local/bin/
 
 ## Options
 
--   `--hetzner-api-token`: **required**. Your project-specific access token for the Hetzner Cloud API.
--   `--hetzner-image`: The name of the Hetzner Cloud image to use, see [Images API](https://docs.hetzner.cloud/#resources-images-get) for how to get a list  (defaults to `ubuntu-16.04`).
--   `--hetzner-server-type`: The type of the Hetzner Cloud server, see [Server Types API](https://docs.hetzner.cloud/#resources-server-types-get) for how to get a list (defaults to `cx11`).
--   `--hetzner-server-location`: The location to create the server in, see [Locations API](https://docs.hetzner.cloud/#resources-locations-get) for how to get a list.
+- `--hetzner-api-token`: **required**. Your project-specific access token for the Hetzner Cloud API.
+- `--hetzner-image`: The name of the Hetzner Cloud image to use, see [Images API](https://docs.hetzner.cloud/#resources-images-get) for how to get a list  (defaults to `ubuntu-16.04`).
+- `--hetzner-server-type`: The type of the Hetzner Cloud server, see [Server Types API](https://docs.hetzner.cloud/#resources-server-types-get) for how to get a list (defaults to `cx11`).
+- `--hetzner-server-location`: The location to create the server in, see [Locations API](https://docs.hetzner.cloud/#resources-locations-get) for how to get a list.
 **NOTICE: Beware that Hetzner does not reject invalid location names at the time of writing this; instead, a seemingly random location is chosen. Double check both the option value's
 spelling and the newly created server to make sure the desired location was chosen indeed.**
--   `--hetzner-existing-key-path`: Use an existing (local) SSH key instead of generating a new keypair.
--   `--hetzner-existing-key-id`: **requires `--hetzner-existing-key-path`**. Use an existing (remote) SSH key instead of uploading the imported key pair,
-    see [SSH Keys API](https://docs.hetzner.cloud/#resources-ssh-keys-get) for how to get a list
+- `--hetzner-existing-key-path`: Use an existing (local) SSH key instead of generating a new keypair.
+- `--hetzner-existing-key-id`: **requires `--hetzner-existing-key-path`**. Use an existing (remote) SSH key instead of uploading the imported key pair,
+  see [SSH Keys API](https://docs.hetzner.cloud/#resources-ssh-keys-get) for how to get a list
+- `--hetzner-user-data`: Cloud-init based User data
 
 #### Existing SSH keys
 
@@ -76,6 +77,7 @@ was used during creation.
 | `--hetzner-server-location`         | `HETZNER_LOCATION`                | - *(let Hetzner choose)*   |
 | `--hetzner-existing-key-path`       | `HETZNER_EXISTING_KEY_PATH`       | - *(generate new keypair)* |
 | `--hetzner-existing-key-id`         | `HETZNER_EXISTING_KEY_ID`         | 0 *(upload new key)*       |
+| `--hetzner-user-data`               | `HETZNER_USER_DATA`               | -                          |
 
 
 ## Building from source

driver.go

@@ -35,6 +35,7 @@ type Driver struct {
 	originalKey    string
 	danglingKey    bool
 	ServerID       int
+	userData       string
 	cachedServer   *hcloud.Server
 }
 
@@ -48,6 +49,7 @@ const (
 	flagLocation  = "hetzner-server-location"
 	flagExKeyID   = "hetzner-existing-key-id"
 	flagExKeyPath = "hetzner-existing-key-path"
+	flagUserData  = "hetzner-user-data"
 )
 
 func NewDriver() *Driver {
@@ -105,6 +107,12 @@ func (d *Driver) GetCreateFlags() []mcnflag.Flag {
 			Usage:  "Path to existing key (new public key will be created unless --hetzner-existing-key-id is specified)",
 			Value:  "",
 		},
+		mcnflag.StringFlag{
+			EnvVar: "HETZNER_USER_DATA",
+			Name:   flagUserData,
+			Usage:  "Cloud-init based User data",
+			Value:  "",
+		},
 	}
 }
 
@@ -116,13 +124,13 @@ func (d *Driver) SetConfigFromFlags(opts drivers.DriverOptions) error {
 	d.KeyID = opts.Int(flagExKeyID)
 	d.IsExistingKey = d.KeyID != 0
 	d.originalKey = opts.String(flagExKeyPath)
+	d.userData = opts.String(flagUserData)
 
 	d.SetSwarmConfigFromFlags(opts)
 
 	if d.AccessToken == "" {
 		return errors.Errorf("hetzner requires --%v to be set", flagAPIToken)
 	}
-
 	return nil
 }
 
@@ -208,7 +216,10 @@ func (d *Driver) Create() error {
 
 	log.Infof("Creating Hetzner server...")
 
-	srvopts := hcloud.ServerCreateOpts{Name: d.GetMachineName()}
+	srvopts := hcloud.ServerCreateOpts{
+		Name:     d.GetMachineName(),
+		UserData: d.userData,
+	}
 
 	var err error
 	if srvopts.Location, err = d.getLocation(); err != nil {