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| 1 | +// Copyright (c) 2026 Uber Technologies, Inc. |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +package hook |
| 16 | + |
| 17 | +import ( |
| 18 | + "fmt" |
| 19 | + "strconv" |
| 20 | + "strings" |
| 21 | +) |
| 22 | + |
| 23 | +// Consumers never parse an id, so this is a minting convention rather than a |
| 24 | +// wire format. All it must guarantee is that two different transitions cannot |
| 25 | +// join to the same string. |
| 26 | +const idSeparator = "/" |
| 27 | + |
| 28 | +// NewEventID mints the id of an event describing a versioned state write. |
| 29 | +// |
| 30 | +// Deriving the id rather than randomizing it is what makes replay safe: the same |
| 31 | +// transition mints the same id, so the queue dedupes a redelivery and a hook |
| 32 | +// stays idempotent without a publisher-side outbox. version is the subject's |
| 33 | +// version immediately after the write, which is what separates two transitions |
| 34 | +// of the same subject. |
| 35 | +func NewEventID(source, eventType, subjectID string, version int32) string { |
| 36 | + return strings.Join([]string{source, eventType, subjectID, strconv.Itoa(int(version))}, idSeparator) |
| 37 | +} |
| 38 | + |
| 39 | +// NewUnversionedEventID mints the id of an event whose transition was not a |
| 40 | +// versioned write, so no version distinguishes one occurrence from the next. |
| 41 | +// |
| 42 | +// The causing message's id stands in for the version, being stable across |
| 43 | +// redeliveries for the same reason a version is. ordinal separates several |
| 44 | +// same-typed events published for one cause; pass 0 when there is only one. |
| 45 | +func NewUnversionedEventID(source, eventType, subjectID, causeID string, ordinal int) string { |
| 46 | + return strings.Join( |
| 47 | + []string{source, eventType, subjectID, causeID, strconv.Itoa(ordinal)}, |
| 48 | + idSeparator, |
| 49 | + ) |
| 50 | +} |
| 51 | + |
| 52 | +// Validate reports whether e carries the three envelope fields every consumer |
| 53 | +// keys on. The rest cannot be checked generically: version is legitimately 0 for |
| 54 | +// an unversioned transition and payload is shaped per type. |
| 55 | +// |
| 56 | +// Both sides call it — a publisher to catch a malformed event before it reaches |
| 57 | +// the queue, a consumer because the producer may not have. |
| 58 | +func Validate(e *HookEvent) error { |
| 59 | + if e == nil { |
| 60 | + return fmt.Errorf("hook event is nil") |
| 61 | + } |
| 62 | + if e.GetId() == "" { |
| 63 | + return fmt.Errorf("hook event has no id") |
| 64 | + } |
| 65 | + if e.GetSource() == "" { |
| 66 | + return fmt.Errorf("hook event %q has no source", e.GetId()) |
| 67 | + } |
| 68 | + if e.GetType() == "" { |
| 69 | + return fmt.Errorf("hook event %q has no type", e.GetId()) |
| 70 | + } |
| 71 | + return nil |
| 72 | +} |
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