From afb159c476719cb11198455616977abd751dad23 Mon Sep 17 00:00:00 2001
From: Pierre-Emmanuel Jacquier
 <15922119+pierre-emmanuelJ@users.noreply.github.com>
Date: Fri, 19 Jan 2024 13:58:00 +0000
Subject: [PATCH] CSI: Implement Expand Volume

Signed-off-by: Pierre-Emmanuel Jacquier <15922119+pierre-emmanuelJ@users.noreply.github.com>
---
 driver/controller.go | 50 ++++++++++++++++++++++++++++++++++++++++++-
 driver/helpers.go    | 51 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/driver/controller.go b/driver/controller.go
index 54432eac..96f09a8a 100644
--- a/driver/controller.go
+++ b/driver/controller.go
@@ -73,7 +73,9 @@ var (
 )
 
 const (
+	// TODO: The API should return it.
 	MinimalVolumeSizeBytes = 100 * 1024 * 1024 * 1024
+	MaximumVolumeSizeBytes = 1000 * 1024 * 1024 * 1024
 )
 
 type controllerService struct {
@@ -605,8 +607,54 @@ func (d *controllerService) ListSnapshots(ctx context.Context, req *csi.ListSnap
 // ControllerExpandVolume resizes/updates the volume (not supported yet on Exoscale Public API)
 func (d *controllerService) ControllerExpandVolume(ctx context.Context, req *csi.ControllerExpandVolumeRequest) (*csi.ControllerExpandVolumeResponse, error) {
 	klog.V(4).Infof("ControllerExpandVolume")
+	zone, volumeID, err := getExoscaleID(req.GetVolumeId())
+	if err != nil {
+		return nil, err
+	}
+	client := d.client.WithURL(zone)
+
+	volume, err := client.GetBlockStorageVolume(ctx, volumeID)
+	if err != nil {
+		if errors.Is(err, v3.ErrNotFound) {
+			return nil, status.Errorf(codes.NotFound, "volume %s not found", volumeID)
+		}
+
+		return nil, err
+	}
+
+	newSize, err := getNewVolumeSize(req.GetCapacityRange())
+	if err != nil {
+		return nil, status.Errorf(codes.OutOfRange, "invalid capacity range: %v", err)
+	}
+
+	if newSize < volume.Size {
+		return nil, status.Error(codes.InvalidArgument, "new size must be bigger than actual volume size")
+	}
+
+	_, err = client.ResizeBlockStorageVolume(ctx, volumeID, v3.ResizeBlockStorageVolumeRequest{
+		Size: newSize,
+	})
+	if err != nil {
+		return nil, err
+	}
 
-	return nil, status.Error(codes.Unimplemented, "")
+	nodeExpansionRequired := true
+	volumeCapability := req.GetVolumeCapability()
+	if volumeCapability != nil {
+		err := validateVolumeCapability(volumeCapability)
+		if err != nil {
+			return nil, status.Errorf(codes.InvalidArgument, "volumeCapabilities not supported: %s", err)
+		}
+
+		if _, ok := volumeCapability.GetAccessType().(*csi.VolumeCapability_Block); ok {
+			nodeExpansionRequired = false
+		}
+	}
+
+	return &csi.ControllerExpandVolumeResponse{
+		CapacityBytes:         newSize,
+		NodeExpansionRequired: nodeExpansionRequired,
+	}, nil
 }
 
 // ControllerGetVolume gets a volume and  return it.
diff --git a/driver/helpers.go b/driver/helpers.go
index c29739f0..bccec8cc 100644
--- a/driver/helpers.go
+++ b/driver/helpers.go
@@ -1,6 +1,7 @@
 package driver
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -94,3 +95,53 @@ func createMountPoint(path string, file bool) error {
 func convertBytesToGibiBytes(nBytes int64) int64 {
 	return nBytes / (1024 * 1024 * 1024)
 }
+
+func getNewVolumeSize(capacityRange *csi.CapacityRange) (int64, error) {
+	if capacityRange == nil {
+		return MinimalVolumeSizeBytes, nil
+	}
+
+	requiredBytes := capacityRange.GetRequiredBytes()
+	requiredSet := requiredBytes > 0
+
+	limitBytes := capacityRange.GetLimitBytes()
+	limitSet := limitBytes > 0
+
+	if !requiredSet && !limitSet {
+		return MinimalVolumeSizeBytes, nil
+	}
+
+	if requiredSet && limitSet && limitBytes < requiredBytes {
+		return 0, errors.New("limit size is less than required size")
+	}
+
+	if requiredSet && !limitSet && requiredBytes < MinimalVolumeSizeBytes {
+		return 0, errors.New("required size is less than the minimun size")
+	}
+
+	if limitSet && limitBytes < MinimalVolumeSizeBytes {
+		return 0, errors.New("limit size is less than the minimun size")
+	}
+
+	if requiredSet && requiredBytes > MaximumVolumeSizeBytes {
+		return 0, errors.New("required size is greater than the maximum size")
+	}
+
+	if !requiredSet && limitSet && limitBytes > MaximumVolumeSizeBytes {
+		return 0, errors.New("limit size is greater than the maximum size")
+	}
+
+	if requiredSet && limitSet && requiredBytes == limitBytes {
+		return requiredBytes, nil
+	}
+
+	if requiredSet {
+		return requiredBytes, nil
+	}
+
+	if limitSet {
+		return limitBytes, nil
+	}
+
+	return MinimalVolumeSizeBytes, nil
+}