Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(35)

Side by Side Diff: appengine/cmd/dm/deps/tmp_get_execution.go

Issue 1537883002: Initial distributor implementation (Closed) Base URL: https://chromium.googlesource.com/external/github.com/luci/luci-go@master
Patch Set: self review Created 4 years, 6 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch
OLDNEW
(Empty)
1 // Copyright 2015 The LUCI Authors. All rights reserved.
2 // Use of this source code is governed under the Apache License, Version 2.0
3 // that can be found in the LICENSE file.
4
5 package deps
6
7 import (
8 crand "crypto/rand" // TODO(iannucci): mock this for testing
9 "encoding/hex"
10
11 "github.com/luci/gae/service/datastore"
12 "github.com/luci/luci-go/appengine/cmd/dm/model"
13 "github.com/luci/luci-go/common/api/dm/service/v1"
14 "github.com/luci/luci-go/common/logging"
15 "github.com/luci/luci-go/common/mathrand"
16 google_pb "github.com/luci/luci-go/common/proto/google"
17 "golang.org/x/net/context"
18 )
19
20 const claimRetries = 8
21
22 // ClaimExecution is a temporary api which searches for and transactionally
23 // claims an execution for an Attempt whose state is NeedsExecution.
24 func (d *deps) ClaimExecution(c context.Context, _ *google_pb.Empty) (rsp *dm.Cl aimExecutionRsp, err error) {
25 // TODO(iannucci): stuff below
26 // It's temporary!! Don't worry about it! :D
27 // Use of GET to mutate state
28 // No 3-way handshake means lost executions
29 ds := datastore.Get(c)
30 l := logging.Get(c)
31
32 exKeyBytes := make([]byte, 32)
33 _, err = crand.Read(exKeyBytes)
34 if err != nil {
35 return
36 }
37 rsp = &dm.ClaimExecutionRsp{
38 Auth: &dm.Execution_Auth{Token: exKeyBytes}}
39
40 for attempts := 0; attempts < claimRetries; attempts++ {
41 q := datastore.NewQuery("Attempt").Eq("State", dm.Attempt_NEEDS_ EXECUTION).Limit(32)
42
43 if attempts < claimRetries-1 {
44 prefixBytes := make([]byte, 2)
45 _, err = crand.Read(prefixBytes)
46 if err != nil {
47 return
48 }
49 prefix := hex.EncodeToString(prefixBytes)
50 l.Infof("Making query (prefix=%s)", prefix)
51 q = q.Gte("__key__", ds.MakeKey("Attempt", prefix))
52 } else {
53 l.Infof("Making query (no prefix)")
54 }
55
56 as := []*model.Attempt{}
57 err = ds.GetAll(q, &as)
58 if err != nil {
59 return
60 }
61 l.Infof("Got %d executions", len(as))
62 if len(as) == 0 {
63 continue
64 }
65
66 // Now find a random one which actually needs execution
67 var aid dm.Attempt_ID
68 for _, i := range mathrand.Get(c).Perm(len(as)) {
69 if as[i].State != dm.Attempt_NEEDS_EXECUTION {
70 continue
71 }
72 aid = as[i].ID
73 }
74 if aid == (dm.Attempt_ID{}) {
75 continue
76 }
77
78 tryAgain := false
79
80 err = ds.RunInTransaction(func(c context.Context) error {
81 ds := datastore.Get(c)
82
83 l.Infof("In TXN for %q", aid)
84 // need to re-read this in the transaction to ensure it really does need
85 // execution still :)
86 a := &model.Attempt{ID: aid}
87 err := ds.Get(a)
88 if err != nil {
89 return err
90 }
91 if a.State != dm.Attempt_NEEDS_EXECUTION {
92 // oops, we picked a bad one, try again in the o uter loop.
93 tryAgain = true
94 return nil
95 }
96
97 err = a.State.Evolve(dm.Attempt_EXECUTING)
98 if err != nil {
99 return err
100 }
101
102 a.CurExecution++
103
104 ex := &model.Execution{
105 ID: a.CurExecution,
106 Attempt: ds.KeyForObj(a),
107 State: dm.Execution_RUNNING,
108 Token: rsp.Auth.Token,
109 }
110 rsp.Auth.Id.Id = a.CurExecution
111 rsp.Auth.Id.Attempt = a.ID.Id
112
113 err = ds.PutMulti([]interface{}{a, ex})
114 if err != nil {
115 return err
116 }
117
118 qst := &model.Quest{ID: aid.Quest}
119 err = datastore.GetNoTxn(c).Get(qst)
120 if err != nil {
121 return err
122 }
123 rsp.Quest = qst.ToProto()
124 return nil
125 }, nil)
126 if tryAgain || err != nil {
127 continue
128 }
129 return
130 }
131
132 rsp = nil
133 return
134 }
OLDNEW

Powered by Google App Engine
This is Rietveld 408576698