open-nomad/client/alloc_endpoint.go
Mahmood Ali ab2cae0625 implement client endpoint of nomad exec
Add a client streaming RPC endpoint for processing nomad exec tasks, by invoking
the relevant task handler for execution.
2019-05-09 16:49:08 -04:00

294 lines
8.3 KiB
Go

package client
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"time"
metrics "github.com/armon/go-metrics"
"github.com/hashicorp/nomad/acl"
cstructs "github.com/hashicorp/nomad/client/structs"
"github.com/hashicorp/nomad/helper"
"github.com/hashicorp/nomad/helper/uuid"
"github.com/hashicorp/nomad/nomad/structs"
nstructs "github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/plugins/drivers"
"github.com/ugorji/go/codec"
)
// Allocations endpoint is used for interacting with client allocations
type Allocations struct {
c *Client
}
func NewAllocationsEndpoint(c *Client) *Allocations {
a := &Allocations{c: c}
a.c.streamingRpcs.Register("Allocations.Exec", a.exec)
return a
}
// GarbageCollectAll is used to garbage collect all allocations on a client.
func (a *Allocations) GarbageCollectAll(args *nstructs.NodeSpecificRequest, reply *nstructs.GenericResponse) error {
defer metrics.MeasureSince([]string{"client", "allocations", "garbage_collect_all"}, time.Now())
// Check node write permissions
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNodeWrite() {
return nstructs.ErrPermissionDenied
}
a.c.CollectAllAllocs()
return nil
}
// GarbageCollect is used to garbage collect an allocation on a client.
func (a *Allocations) GarbageCollect(args *nstructs.AllocSpecificRequest, reply *nstructs.GenericResponse) error {
defer metrics.MeasureSince([]string{"client", "allocations", "garbage_collect"}, time.Now())
// Check submit job permissions
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilitySubmitJob) {
return nstructs.ErrPermissionDenied
}
if !a.c.CollectAllocation(args.AllocID) {
// Could not find alloc
return nstructs.NewErrUnknownAllocation(args.AllocID)
}
return nil
}
// Signal is used to send a signal to an allocation's tasks on a client.
func (a *Allocations) Signal(args *nstructs.AllocSignalRequest, reply *nstructs.GenericResponse) error {
defer metrics.MeasureSince([]string{"client", "allocations", "signal"}, time.Now())
// Check alloc-lifecycle permissions
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilityAllocLifecycle) {
return nstructs.ErrPermissionDenied
}
return a.c.SignalAllocation(args.AllocID, args.Task, args.Signal)
}
// Restart is used to trigger a restart of an allocation or a subtask on a client.
func (a *Allocations) Restart(args *nstructs.AllocRestartRequest, reply *nstructs.GenericResponse) error {
defer metrics.MeasureSince([]string{"client", "allocations", "restart"}, time.Now())
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilityAllocLifecycle) {
return nstructs.ErrPermissionDenied
}
return a.c.RestartAllocation(args.AllocID, args.TaskName)
}
// Stats is used to collect allocation statistics
func (a *Allocations) Stats(args *cstructs.AllocStatsRequest, reply *cstructs.AllocStatsResponse) error {
defer metrics.MeasureSince([]string{"client", "allocations", "stats"}, time.Now())
// Check read job permissions
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilityReadJob) {
return nstructs.ErrPermissionDenied
}
clientStats := a.c.StatsReporter()
aStats, err := clientStats.GetAllocStats(args.AllocID)
if err != nil {
return err
}
stats, err := aStats.LatestAllocStats(args.Task)
if err != nil {
return err
}
reply.Stats = stats
return nil
}
// exec is used to execute command in a running task
func (a *Allocations) exec(conn io.ReadWriteCloser) {
defer metrics.MeasureSince([]string{"client", "allocations", "exec"}, time.Now())
defer conn.Close()
execID := uuid.Generate()
decoder := codec.NewDecoder(conn, structs.MsgpackHandle)
encoder := codec.NewEncoder(conn, structs.MsgpackHandle)
code, err := a.execImpl(encoder, decoder, execID)
if err != nil {
a.c.logger.Info("task exec session ended with an error", "error", err, "code", code)
handleStreamResultError(err, code, encoder)
return
}
a.c.logger.Info("task exec session ended", "exec_id", execID)
}
func (a *Allocations) execImpl(encoder *codec.Encoder, decoder *codec.Decoder, execID string) (code *int64, err error) {
// Decode the arguments
var req cstructs.AllocExecRequest
if err := decoder.Decode(&req); err != nil {
return helper.Int64ToPtr(500), err
}
aclObj, token, err := a.c.resolveTokenAndACL(req.QueryOptions.AuthToken)
{
// log access
tokenName, tokenID := "", ""
if token != nil {
tokenName, tokenID = token.Name, token.AccessorID
}
a.c.logger.Info("task exec session starting",
"exec_id", execID,
"alloc_id", req.AllocID,
"task", req.Task,
"command", req.Cmd,
"tty", req.Tty,
"access_token_name", tokenName,
"access_token_id", tokenID,
)
}
// Check read permissions
if err != nil {
return nil, err
} else if aclObj != nil {
exec := aclObj.AllowNsOp(req.QueryOptions.Namespace, acl.NamespaceCapabilityAllocExec)
if !exec {
return nil, structs.ErrPermissionDenied
}
}
// Validate the arguments
if req.AllocID == "" {
return helper.Int64ToPtr(400), allocIDNotPresentErr
}
if req.Task == "" {
return helper.Int64ToPtr(400), taskNotPresentErr
}
if len(req.Cmd) == 0 {
return helper.Int64ToPtr(400), errors.New("command is not present")
}
ar, err := a.c.getAllocRunner(req.AllocID)
if err != nil {
code := helper.Int64ToPtr(500)
if structs.IsErrUnknownAllocation(err) {
code = helper.Int64ToPtr(404)
}
return code, err
}
capabilities, err := ar.GetTaskDriverCapabilities(req.Task)
if err != nil {
code := helper.Int64ToPtr(500)
if structs.IsErrUnknownAllocation(err) {
code = helper.Int64ToPtr(404)
}
return code, err
}
// check node access
if aclObj != nil && capabilities.FSIsolation == drivers.FSIsolationNone {
exec := aclObj.AllowNsOp(req.QueryOptions.Namespace, acl.NamespaceCapabilityAllocNodeExec)
if !exec {
return nil, structs.ErrPermissionDenied
}
}
allocState, err := a.c.GetAllocState(req.AllocID)
if err != nil {
code := helper.Int64ToPtr(500)
if structs.IsErrUnknownAllocation(err) {
code = helper.Int64ToPtr(404)
}
return code, err
}
// Check that the task is there
taskState := allocState.TaskStates[req.Task]
if taskState == nil {
return helper.Int64ToPtr(400), fmt.Errorf("unknown task name %q", req.Task)
}
if taskState.StartedAt.IsZero() {
return helper.Int64ToPtr(404), fmt.Errorf("task %q not started yet.", req.Task)
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
h := ar.GetTaskExecHandler(req.Task)
if h == nil {
return helper.Int64ToPtr(404), fmt.Errorf("task %q is not running.", req.Task)
}
err = h(ctx, req.Cmd, req.Tty, newExecStream(cancel, decoder, encoder))
if err != nil {
code := helper.Int64ToPtr(500)
return code, err
}
return nil, nil
}
// newExecStream returns a new exec stream as expected by drivers that interpolate with RPC streaming format
func newExecStream(cancelFn func(), decoder *codec.Decoder, encoder *codec.Encoder) drivers.ExecTaskStream {
buf := new(bytes.Buffer)
return &execStream{
cancelFn: cancelFn,
decoder: decoder,
buf: buf,
encoder: encoder,
frameCodec: codec.NewEncoder(buf, structs.JsonHandle),
}
}
type execStream struct {
cancelFn func()
decoder *codec.Decoder
encoder *codec.Encoder
buf *bytes.Buffer
frameCodec *codec.Encoder
}
// Send sends driver output response across RPC mechanism using cstructs.StreamErrWrapper
func (s *execStream) Send(m *drivers.ExecTaskStreamingResponseMsg) error {
s.buf.Reset()
s.frameCodec.Reset(s.buf)
s.frameCodec.MustEncode(m)
return s.encoder.Encode(cstructs.StreamErrWrapper{
Payload: s.buf.Bytes(),
})
}
// Recv returns next exec user input from the RPC to be passed to driver exec handler
func (s *execStream) Recv() (*drivers.ExecTaskStreamingRequestMsg, error) {
req := drivers.ExecTaskStreamingRequestMsg{}
err := s.decoder.Decode(&req)
if err == io.EOF || err == io.ErrClosedPipe {
s.cancelFn()
}
return &req, err
}