Added support for nitro instances with NVMe block devices (#38)

Gopkg.toml

@@ -5,3 +5,7 @@
 [[constraint]]
   branch = "master"
   name = "github.com/sirupsen/logrus"
+
+[[constraint]]
+  name = "github.com/mvisonneau/go-ebsnvme"
+  version = "0.1.0"

attach.go

@@ -35,14 +35,14 @@ func (e *EC2Instance) AttachEbsVolumes() {
 					volLogger.Fatalf("Couldn't attach: %v", err)
 				}
 				volLogger.Info(volAttachments)
-				volume.AttachedName = deviceName
 
 				if !filesystem.DoesDriveExistWithTimeout(deviceName, 10) {
 					volLogger.Fatalf("Drive %s doesn't exist after attaching - checked with stat 10 times", deviceName)
 				}
+
+				volume.AttachedName = deviceName
 				localVolumes[key] = append(localVolumes[key], volume)
 			}
-
 		}
 	}
 	e.Vols = localVolumes

ebs.go

@@ -55,7 +55,11 @@ func prepAndMountDrives(volName string, vols []EbsVol) {
 		var err error
 		if len(vols) == 1 {
 			driveLogger.Info("Single drive, no RAID")
-			driveName = vols[0].AttachedName
+			driveName, err = filesystem.GetActualBlockDeviceName(vols[0].AttachedName)
+			if err != nil {
+				driveLogger.Fatalf("Block device is not available %s : %v", vols[0].AttachedName, err)
+			}
+			driveLogger.Infof("Using %s as local block device", driveName)
 		} else {
 			if raidLevel == -1 {
 				driveLogger.Info("Raid level not provided, not performing further actions")
@@ -64,7 +68,12 @@ func prepAndMountDrives(volName string, vols []EbsVol) {
 			driveLogger.Info("Creating RAID array")
 			driveNames := []string{}
 			for _, vol := range vols {
-				driveNames = append(driveNames, vol.AttachedName)
+				driveName, err = filesystem.GetActualBlockDeviceName(vol.AttachedName)
+				if err != nil {
+					driveLogger.Fatalf("Block device is not available %s : %v", vol.AttachedName, err)
+				}
+				driveLogger.Infof("Using %s as local block device", driveName)
+				driveNames = append(driveNames, driveName)
 			}
 			if driveName, err = filesystem.CreateRaidArray(driveNames, volName, raidLevel); err != nil {
 				driveLogger.Fatalf("Error when creating reaid array: %v", err)

filesystem/drive.go

@@ -1,9 +1,12 @@
 package filesystem
 
 import (
+	"os"
+	"path/filepath"
+	"regexp"
 	"time"
 
-	"github.com/sevagh/goat/execute"
+	"github.com/mvisonneau/go-ebsnvme/pkg/ebsnvme"
 )
 
 //DoesDriveExistWithTimeout makes 10 attempts, 2 second sleep between each, to stat a drive to check for its existence
@@ -21,8 +24,38 @@ func DoesDriveExistWithTimeout(driveName string, maxAttempts int) bool {
 
 //DoesDriveExist does a single stat call to check if a drive exists
 func DoesDriveExist(driveName string) bool {
-	if _, err := execute.Command("stat", []string{driveName}, ""); err != nil {
+	if _, err := os.Stat(driveName); os.IsNotExist(err) {
+		for _, file := range listNvmeBlockDevices() {
+			if d, _ := ebsnvme.ScanDevice(file); d.Name == driveName {
+				return true
+			}
+		}
 		return false
 	}
 	return true
 }
+
+// GetLocalBlockDeviceName returns the actual name of the block device seen
+// within the instance (useful for nitros)
+func GetActualBlockDeviceName(name string) (string, error) {
+	for _, device := range listNvmeBlockDevices() {
+		if d, _ := ebsnvme.ScanDevice(device); d.Name == name {
+			return device, nil
+		}
+	}
+	if _, err := os.Stat(name); os.IsNotExist(err) {
+		return "", err
+	}
+	return name, nil
+}
+
+func listNvmeBlockDevices() (devices []string) {
+	re := regexp.MustCompile("(^\\/dev\\/nvme[0-9]+n1$)")
+	f, _ := filepath.Glob("/dev/nvme*")
+	for _, d := range f {
+		if re.Match([]byte(d)) {
+			devices = append(devices, d)
+		}
+	}
+	return
+}