Make volume size configurable

Support specifying a volume size in GB via volume options.

Author: jgraichen

README.md

@@ -12,7 +12,7 @@ The plugin attaches block storage volumes to the compute instance running the pl
 * KVM w/ virtio
 
 
-## Usage
+## Setup
 
 Provide configuration for the plugin:
 
@@ -44,6 +44,14 @@ INFO Connected.                                    endpoint="http://api.os.xopic
 
 By default a `cinder.json` from the current working directory will be used.
 
+## Usage
+
+The default volume size is 10GB but can be overridden:
+
+```
+$ docker volume create -d cinder -o size=20 volname
+```
+
 
 ## Notes
 

plugin.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 	"syscall"
@@ -84,8 +85,20 @@ func (d plugin) Create(r *volume.CreateRequest) error {
 	d.mutex.Lock()
 	defer d.mutex.Unlock()
 
+	// DEFAULT SIZE IN GB
+	var size = 10
+	var err error
+
+	if s, ok := r.Options["size"]; ok {
+		size, err = strconv.Atoi(s)
+		if err != nil {
+			logger.WithError(err).Error("Error parsing size option")
+			return fmt.Errorf("Invalid size option: %s", err.Error())
+		}
+	}
+
 	vol, err := volumes.Create(d.blockClient, volumes.CreateOpts{
-		Size: 10,
+		Size: size,
 		Name: r.Name,
 	}).Extract()