Added basic topology support to driver

Author: davidz627

pkg/gce-pd-csi-driver/controller.go

@@ -95,6 +95,27 @@ func (gceCS *GCEControllerServer) CreateVolume(ctx context.Context, req *csi.Cre
 		}
 	}
 
+	// Topology overwrites Storage Class Params if specified
+	// TODO: Support preferred toplogies.
+	if req.GetAccessibilityRequirements() != nil {
+		reqTop := req.GetAccessibilityRequirements().GetRequisite()
+		if reqTop == nil || len(reqTop) == 0 {
+			return nil, status.Error(codes.InvalidArgument, fmt.Sprintf("CreateVolume accessibility requirements specified but no requisite topologies"))
+		}
+		if reqTop[0].GetSegments() == nil {
+			return nil, status.Error(codes.InvalidArgument, fmt.Sprintf("CreateVolume requisite toplogies specified specified but no segments"))
+		}
+		// Currently just pick the 0th requisite toplogy. This is a valid strategy but
+		// we may want to randomly cycle in the future (?)
+		zoneSeg, ok := reqTop[0].GetSegments()["zone"]
+		if ok {
+			configuredZone = zoneSeg
+		} else {
+			return nil, status.Error(codes.InvalidArgument,
+				fmt.Sprintf("CreateVolume requisite topology specified but could not find zone in segment: %v", reqTop[0].GetSegments()))
+		}
+	}
+
 	createResp := &csi.CreateVolumeResponse{
 		Volume: &csi.Volume{
 			CapacityBytes: capBytes,

pkg/gce-pd-csi-driver/identity.go

@@ -51,6 +51,13 @@ func (gceIdentity *GCEIdentityServer) GetPluginCapabilities(ctx context.Context,
 					},
 				},
 			},
+			{
+				Type: &csi.PluginCapability_Service_{
+					Service: &csi.PluginCapability_Service{
+						Type: csi.PluginCapability_Service_ACCESSIBILITY_CONSTRAINTS,
+					},
+				},
+			},
 		},
 	}, nil
 }

pkg/gce-pd-csi-driver/node.go

@@ -19,6 +19,8 @@ import (
 	"os"
 	"sync"
 
+	"cloud.google.com/go/compute/metadata"
+
 	csi "github.com/container-storage-interface/spec/lib/go/csi/v0"
 	"github.com/golang/glog"
 	"golang.org/x/net/context"
@@ -270,12 +272,22 @@ func (ns *GCENodeServer) NodeGetCapabilities(ctx context.Context, req *csi.NodeG
 func (ns *GCENodeServer) NodeGetInfo(ctx context.Context, req *csi.NodeGetInfoRequest) (*csi.NodeGetInfoResponse, error) {
 	glog.Infof("NodeGetInfo called with req: %#v", req)
 
+	zone, err := metadata.Zone()
+	if err != nil {
+		return nil, status.Error(codes.Internal, fmt.Sprintf("NodeGetInfo failed to get zone from instance metadata: %v", err))
+	}
+
+	top := &csi.Topology{
+		Segments: map[string]string{"zone": zone},
+	}
+
 	resp := &csi.NodeGetInfoResponse{
 		NodeId: ns.Driver.nodeID,
 		// TODO: Set MaxVolumesPerNode based on Node Type
 		// Default of 0 means that CO Decides how many nodes can be published
+		// Can get from metadata server "machine-type"
 		MaxVolumesPerNode:  0,
-		AccessibleTopology: nil,
+		AccessibleTopology: top,
 	}
 	return resp, nil
 }