open-nomad/client/alloc_endpoint.go
Tim Gross c24f4d9925
client: improve alloc GC API error messages (#9488)
The client allocation GC API returns a misleading error message when the
allocation exists but is not yet eligible for GC. Make this clear in the error
response.

Note in the docs that the allocation will still show on the server responses.
2021-01-04 11:34:12 -05:00

311 lines
8.6 KiB
Go

package client
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"time"
metrics "github.com/armon/go-metrics"
"github.com/hashicorp/go-msgpack/codec"
"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"
)
// 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())
alloc, err := a.c.GetAlloc(args.AllocID)
if err != nil {
return err
}
// Check namespace submit job permission.
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(alloc.Namespace, acl.NamespaceCapabilitySubmitJob) {
return nstructs.ErrPermissionDenied
}
if !a.c.CollectAllocation(args.AllocID) {
return fmt.Errorf("No such allocation on client, or allocation not eligible for GC")
}
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())
alloc, err := a.c.GetAlloc(args.AllocID)
if err != nil {
return err
}
// Check namespace alloc-lifecycle permission.
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(alloc.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())
alloc, err := a.c.GetAlloc(args.AllocID)
if err != nil {
return err
}
// Check namespace alloc-lifecycle permission.
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(alloc.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())
alloc, err := a.c.GetAlloc(args.AllocID)
if err != nil {
return err
}
// Check read-job permission.
if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
return err
} else if aclObj != nil && !aclObj.AllowNsOp(alloc.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
}
if a.c.GetConfig().DisableRemoteExec {
return nil, structs.ErrPermissionDenied
}
if req.AllocID == "" {
return helper.Int64ToPtr(400), allocIDNotPresentErr
}
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
}
alloc := ar.Alloc()
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 alloc-exec permission.
if err != nil {
return nil, err
} else if aclObj != nil && !aclObj.AllowNsOp(alloc.Namespace, acl.NamespaceCapabilityAllocExec) {
return nil, structs.ErrPermissionDenied
}
// Validate the arguments
if req.Task == "" {
return helper.Int64ToPtr(400), taskNotPresentErr
}
if len(req.Cmd) == 0 {
return helper.Int64ToPtr(400), errors.New("command is not present")
}
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(alloc.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(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(decoder *codec.Decoder, encoder *codec.Encoder) drivers.ExecTaskStream {
buf := new(bytes.Buffer)
return &execStream{
decoder: decoder,
buf: buf,
encoder: encoder,
frameCodec: codec.NewEncoder(buf, structs.JsonHandle),
}
}
type execStream struct {
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)
return &req, err
}