open-nomad/client/client_csi_endpoint.go
2020-03-23 13:58:28 -04:00

103 lines
3.1 KiB
Go

package client
import (
"context"
"errors"
"fmt"
"time"
metrics "github.com/armon/go-metrics"
"github.com/hashicorp/nomad/client/dynamicplugins"
"github.com/hashicorp/nomad/client/structs"
"github.com/hashicorp/nomad/plugins/csi"
)
// ClientCSI endpoint is used for interacting with CSI plugins on a client.
// TODO: Submit metrics with labels to allow debugging per plugin perf problems.
type ClientCSI struct {
c *Client
}
const (
// CSIPluginRequestTimeout is the timeout that should be used when making reqs
// against CSI Plugins. It is copied from Kubernetes as an initial seed value.
// https://github.com/kubernetes/kubernetes/blob/e680ad7156f263a6d8129cc0117fda58602e50ad/pkg/volume/csi/csi_plugin.go#L52
CSIPluginRequestTimeout = 2 * time.Minute
)
var (
ErrPluginTypeError = errors.New("CSI Plugin loaded incorrectly")
)
// CSIControllerAttachVolume is used to attach a volume from a CSI Cluster to
// the storage node provided in the request.
//
// The controller attachment flow currently works as follows:
// 1. Validate the volume request
// 2. Call ControllerPublishVolume on the CSI Plugin to trigger a remote attachment
//
// In the future this may be expanded to request dynamic secrets for attachement.
func (c *ClientCSI) CSIControllerAttachVolume(req *structs.ClientCSIControllerAttachVolumeRequest, resp *structs.ClientCSIControllerAttachVolumeResponse) error {
defer metrics.MeasureSince([]string{"client", "csi_controller", "publish_volume"}, time.Now())
plugin, err := c.findControllerPlugin(req.PluginName)
if err != nil {
return err
}
defer plugin.Close()
// The following block of validation checks should not be reached on a
// real Nomad cluster as all of this data should be validated when registering
// volumes with the cluster. They serve as a defensive check before forwarding
// requests to plugins, and to aid with development.
if req.VolumeID == "" {
return errors.New("VolumeID is required")
}
if req.NodeID == "" {
return errors.New("NodeID is required")
}
if !structs.ValidCSIVolumeAccessMode(req.AccessMode) {
return fmt.Errorf("Unknown access mode: %v", req.AccessMode)
}
if !structs.ValidCSIVolumeAttachmentMode(req.AttachmentMode) {
return fmt.Errorf("Unknown attachment mode: %v", req.AttachmentMode)
}
// Submit the request for a volume to the CSI Plugin.
ctx, cancelFn := c.requestContext()
defer cancelFn()
cresp, err := plugin.ControllerPublishVolume(ctx, req.ToCSIRequest())
if err != nil {
return err
}
resp.PublishContext = cresp.PublishContext
return nil
}
func (c *ClientCSI) findControllerPlugin(name string) (csi.CSIPlugin, error) {
return c.findPlugin(dynamicplugins.PluginTypeCSIController, name)
}
// TODO: Cache Plugin Clients?
func (c *ClientCSI) findPlugin(ptype, name string) (csi.CSIPlugin, error) {
pIface, err := c.c.dynamicRegistry.DispensePlugin(ptype, name)
if err != nil {
return nil, err
}
plugin, ok := pIface.(csi.CSIPlugin)
if !ok {
return nil, ErrPluginTypeError
}
return plugin, nil
}
func (c *ClientCSI) requestContext() (context.Context, context.CancelFunc) {
return context.WithTimeout(context.Background(), CSIPluginRequestTimeout)
}