open-nomad/nomad/client_stats_endpoint.go
Michael Schurter 88a9409f8e rpc: only attempt NodeRpc for nodes>=0.8
Attempting NodeRpc (or streaming node rpc) for clients that do not
support it causes it to hang indefinitely because while the TCP
connection exists, the client will never respond.
2018-04-09 11:08:06 -07:00

83 lines
2 KiB
Go

package nomad
import (
"errors"
"fmt"
"time"
metrics "github.com/armon/go-metrics"
"github.com/hashicorp/nomad/client/structs"
nstructs "github.com/hashicorp/nomad/nomad/structs"
)
// ClientStats is used to forward RPC requests to the targed Nomad client's
// ClientStats endpoint.
type ClientStats struct {
srv *Server
}
func (s *ClientStats) Stats(args *nstructs.NodeSpecificRequest, reply *structs.ClientStatsResponse) error {
// We only allow stale reads since the only potentially stale information is
// the Node registration and the cost is fairly high for adding another hope
// in the forwarding chain.
args.QueryOptions.AllowStale = true
// Potentially forward to a different region.
if done, err := s.srv.forward("ClientStats.Stats", args, args, reply); done {
return err
}
defer metrics.MeasureSince([]string{"nomad", "client_stats", "stats"}, time.Now())
// Check node read permissions
if aclObj, err := s.srv.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNodeRead() {
return nstructs.ErrPermissionDenied
}
// Verify the arguments.
if args.NodeID == "" {
return errors.New("missing NodeID")
}
// Check if the node even exists and is compatible with NodeRpc
snap, err := s.srv.State().Snapshot()
if err != nil {
return err
}
node, err := snap.NodeByID(nil, args.NodeID)
if err != nil {
return err
}
if node == nil {
return fmt.Errorf("Unknown node %q", args.NodeID)
}
// Make sure Node is new enough to support RPC
if err := nodeSupportsRpc(node); err != nil {
return err
}
// Get the connection to the client
state, ok := s.srv.getNodeConn(args.NodeID)
if !ok {
// Determine the Server that has a connection to the node.
srv, err := s.srv.serverWithNodeConn(args.NodeID, s.srv.Region())
if err != nil {
return err
}
if srv == nil {
return nstructs.ErrNoNodeConn
}
return s.srv.forwardServer(srv, "ClientStats.Stats", args, reply)
}
// Make the RPC
return NodeRpc(state.Session, "ClientStats.Stats", args, reply)
}