carlos / platform Public

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1	package hostbox
2
3	import (
4	"context"
5	"encoding/hex"
6	"reflect"
7	"time"
8	)
9
10	// Parking selectors carry identities only. Root derives all paths, receipts,
11	// sizes and deadlines independently.
12	type ServingArtifactIdentity struct {
13	Host, Box, Region, Incarnation, Location, Generation string
14	Stamp, Session uint64
15	}
16
17	type ServingArtifactDirectory struct {
18	Device, Inode, Mount uint64
19	}
20
21	type ServingLegacyPredecessor struct {
22	Session uint64
23	Generation string
24	Empty bool
25	}
26
27	type ServingParkRequest struct {
28	Successor ServingArtifactIdentity
29	Predecessor ServingArtifactIdentity
30	Legacy ServingLegacyPredecessor
31	Retirement string
32	}
33
34	type ServingParkResult struct {
35	TagsFrom uint64
36	ID string
37	Legacy bool
38	Predecessor ServingArtifactIdentity
39	OriginalSuccessor ServingArtifactIdentity
40	Successor ServingArtifactIdentity
41	Directory ServingArtifactDirectory
42	}
43
44	// Keep this tuple frozen when the public wire structs grow.
45	func journalServingParkV4(p *ServingParkRequest) any {
46	if p == nil {
47	return nil
48	}
49	identity := func(s ServingArtifactIdentity) any {
50	return []any{s.Host, s.Box, s.Region, s.Incarnation, s.Location, s.Generation, s.Stamp, s.Session}
51	}
52	return []any{identity(p.Successor), identity(p.Predecessor), p.Legacy.Session, p.Legacy.Generation, p.Legacy.Empty, p.Retirement}
53	}
54
55	func ServingParkOperation(op string) bool {
56	return op == "serving-park" || op == "serving-park-legacy" || op == "serving-park-complete" || op == "serving-park-pressure"
57	}
58
59	func validateServingParkRequest(q JournalRequest) error {
60	if q.V != 4 || q.ServingPark == nil || !ServingParkOperation(q.Op) {
61	return ErrTypedJournal
62	}
63	// Reject every field belonging to a different journal operation, including
64	// fields omitted from v4's hash. Only these selectors are remotely writable.
65	canonical := JournalRequest{V: q.V, ID: q.ID, Op: q.Op, Nonce: q.Nonce, IssuedAt: q.IssuedAt, ServingPark: q.ServingPark}
66	if !reflect.DeepEqual(q, canonical) {
67	return ErrTypedJournal
68	}
69	nonce, err := hex.DecodeString(q.Nonce)
70	if err != nil || len(nonce) != 16 || q.IssuedAt <= 0 {
71	return ErrTypedJournal
72	}
73	if q.ID != journalRequestID(q) {
74	return ErrChanged
75	}
76	p := *q.ServingPark
77	s := p.Successor
78	if s.Host == "" || s.Box == "" || s.Region == "" || s.Incarnation == "" || s.Location == "" || s.Generation == "" || s.Stamp == 0 || s.Session != s.Stamp {
79	return ErrTypedJournal
80	}
81	switch q.Op {
82	case "serving-park":
83	if p.Legacy != (ServingLegacyPredecessor{}) || p.Retirement != "" {
84	return ErrTypedJournal
85	}
86	case "serving-park-legacy":
87	if p.Predecessor != (ServingArtifactIdentity{}) || p.Retirement != "" || (p.Legacy.Session == 0) != (p.Legacy.Generation == "") || p.Legacy.Session >= s.Session || (p.Legacy.Empty && p.Legacy.Session != 0) {
88	return ErrTypedJournal
89	}
90	case "serving-park-complete":
91	id, err := hex.DecodeString(p.Retirement)
92	if err != nil || len(id) != 32 || p.Predecessor != (ServingArtifactIdentity{}) || p.Legacy != (ServingLegacyPredecessor{}) {
93	return ErrTypedJournal
94	}
95	case "serving-park-pressure":
96	// Pressure also needs a preadmission observed-claim selector. It remains
97	// unavailable until the independent sizing and relief mechanism exists.
98	return ErrUnsupported
99	}
100	return nil
101	}
102
103	type ServingParkClient struct{ Call JournalCall }
104
105	func (c ServingParkClient) request(ctx context.Context, op string, p ServingParkRequest) (ServingParkResult, error) {
106	if c.Call == nil {
107	return ServingParkResult{}, ErrUnsupported
108	}
109	q, err := journalPrepare(JournalRequest{Op: op, ServingPark: &p}, time.Now())
110	if err != nil {
111	return ServingParkResult{}, err
112	}
113	out, err := journalSend(ctx, c.Call, q, false)
114	if err != nil {
115	return ServingParkResult{}, err
116	}
117	if err = servingParkResponse(q, out); err != nil {
118	return ServingParkResult{}, err
119	}
120	return *out.ServingPark, nil
121	}
122
123	func (c ServingParkClient) Park(ctx context.Context, successor, predecessor ServingArtifactIdentity) (ServingParkResult, error) {
124	return c.request(ctx, "serving-park", ServingParkRequest{Successor: successor, Predecessor: predecessor})
125	}
126
127	func (c ServingParkClient) ParkLegacy(ctx context.Context, successor ServingArtifactIdentity, predecessor ServingLegacyPredecessor) (ServingParkResult, error) {
128	return c.request(ctx, "serving-park-legacy", ServingParkRequest{Successor: successor, Legacy: predecessor})
129	}
130
131	func (c ServingParkClient) Complete(ctx context.Context, id string, successor ServingArtifactIdentity) error {
132	_, err := c.request(ctx, "serving-park-complete", ServingParkRequest{Successor: successor, Retirement: id})
133	return err
134	}
135
136	func (c ServingParkClient) ReplayUncertain(ctx context.Context, uncertain *JournalUncertainError) (JournalResponse, error) {
137	if c.Call == nil || uncertain == nil || validateServingParkRequest(uncertain.Request) != nil {
138	return JournalResponse{}, ErrUnsupported
139	}
140	out, err := journalSend(ctx, c.Call, uncertain.Request, true)
141	if err == nil {
142	err = servingParkResponse(uncertain.Request, out)
143	}
144	return out, err
145	}
146
147	func servingParkResponse(q JournalRequest, out JournalResponse) error {
148	p := q.ServingPark
149	if p == nil || out.ServingPark == nil || out.ServingPark.Successor != p.Successor || out.ServingPark.ID == "" || (p.Retirement != "" && out.ServingPark.ID != p.Retirement) {
150	return &JournalUncertainError{Request: q, Cause: ErrJournalUncertain}
151	}
152	return nil
153	}
154