| 1 | package session |
| 2 | |
| 3 | import ( |
| 4 | "encoding/json" |
| 5 | "errors" |
| 6 | "fmt" |
| 7 | "strings" |
| 8 | |
| 9 | "reasonix/internal/provider" |
| 10 | ) |
| 11 | |
| 12 | type messageRetractPayload struct { |
| 13 | MessageIDs []string `json:"messageIds"` |
| 14 | Reason string `json:"reason,omitempty"` |
| 15 | } |
| 16 | |
| 17 | func retractedMessageIDs(event Event, payload json.RawMessage) ([]string, error) { |
| 18 | var body messageRetractPayload |
| 19 | if err := strictPayload(payload, &body); err != nil { |
| 20 | return nil, damagedPayload(event, err) |
| 21 | } |
| 22 | if len(body.MessageIDs) == 0 { |
| 23 | return nil, damagedPayload(event, fmt.Errorf("empty messageIds")) |
| 24 | } |
| 25 | seen := make(map[string]bool, len(body.MessageIDs)) |
| 26 | for _, id := range body.MessageIDs { |
| 27 | if strings.TrimSpace(id) == "" || strings.TrimSpace(id) != id || seen[id] { |
| 28 | return nil, damagedPayload(event, fmt.Errorf("invalid or duplicate message id")) |
| 29 | } |
| 30 | seen[id] = true |
| 31 | } |
| 32 | return body.MessageIDs, nil |
| 33 | } |
| 34 | |
| 35 | // Execution, recovery, history and search must decode the same durable event |
| 36 | // schema. Projection-specific DTOs used to reject valid rewrite/import metadata. |
| 37 | type historyReplacePayload struct { |
| 38 | Messages []provider.Message `json:"messages"` |
| 39 | Reason string `json:"reason,omitempty"` |
| 40 | Sources []uint64 `json:"sourceSequences,omitempty"` |
| 41 | } |
| 42 | |
| 43 | type legacyImportPayload struct { |
| 44 | Source Source `json:"source"` |
| 45 | Messages []provider.Message `json:"messages"` |
| 46 | Goal json.RawMessage `json:"goal,omitempty"` |
| 47 | ModelRef string `json:"modelRef,omitempty"` |
| 48 | ModelIdentity string `json:"modelIdentity,omitempty"` |
| 49 | } |
| 50 | |
| 51 | // ErrDuplicateMessageID refuses a write that would give two messages one |
| 52 | // stable id; every reader of the log keys a message by that id. |
| 53 | var ErrDuplicateMessageID = errors.New("session: duplicate stable message id") |
| 54 | |
| 55 | // replacementEventMessages keeps the first occurrence of each id, so a log |
| 56 | // written before the writer refused duplicates projects and indexes alike. |
| 57 | func replacementEventMessages(event Event, payload json.RawMessage) ([]provider.Message, error) { |
| 58 | messages, err := decodeReplacementMessages(event, payload) |
| 59 | if err != nil { |
| 60 | return nil, err |
| 61 | } |
| 62 | return firstMessageOccurrences(messages), nil |
| 63 | } |
| 64 | |
| 65 | func decodeReplacementMessages(event Event, payload json.RawMessage) ([]provider.Message, error) { |
| 66 | var messages []provider.Message |
| 67 | var err error |
| 68 | if event.Kind == "legacy/import" { |
| 69 | var body legacyImportPayload |
| 70 | err = strictPayload(payload, &body) |
| 71 | messages = body.Messages |
| 72 | } else { |
| 73 | var body historyReplacePayload |
| 74 | err = strictPayload(payload, &body) |
| 75 | messages = body.Messages |
| 76 | } |
| 77 | if err != nil || messages == nil { |
| 78 | return nil, damagedPayload(event, err) |
| 79 | } |
| 80 | return messages, nil |
| 81 | } |
| 82 | |
| 83 | func firstMessageOccurrences(messages []provider.Message) []provider.Message { |
| 84 | if _, duplicated := duplicateMessageID(messages); !duplicated { |
| 85 | return messages |
| 86 | } |
| 87 | seen := make(map[string]bool, len(messages)) |
| 88 | unique := make([]provider.Message, 0, len(messages)) |
| 89 | for _, message := range messages { |
| 90 | if message.ID != "" && seen[message.ID] { |
| 91 | continue |
| 92 | } |
| 93 | seen[message.ID] = true |
| 94 | unique = append(unique, message) |
| 95 | } |
| 96 | return unique |
| 97 | } |
| 98 | |
| 99 | func duplicateMessageID(messages []provider.Message) (string, bool) { |
| 100 | seen := make(map[string]bool, len(messages)) |
| 101 | for _, message := range messages { |
| 102 | if message.ID == "" { |
| 103 | continue |
| 104 | } |
| 105 | if seen[message.ID] { |
| 106 | return message.ID, true |
| 107 | } |
| 108 | seen[message.ID] = true |
| 109 | } |
| 110 | return "", false |
| 111 | } |
| 112 | |
| 113 | // checkReplacementIdentities refuses a new replacement that repeats an id. A |
| 114 | // payload that does not decode is the projection's to refuse. |
| 115 | func checkReplacementIdentities(event Event) error { |
| 116 | if event.Kind != "history/replace" && event.Kind != "legacy/import" { |
| 117 | return nil |
| 118 | } |
| 119 | messages, err := decodeReplacementMessages(event, event.Payload) |
| 120 | if err != nil { |
| 121 | return nil |
| 122 | } |
| 123 | if id, duplicated := duplicateMessageID(messages); duplicated { |
| 124 | return fmt.Errorf("%w: %s message %q", ErrDuplicateMessageID, event.Kind, id) |
| 125 | } |
| 126 | return nil |
| 127 | } |
| 128 |