|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "fmt" |
| 6 | + "time" |
| 7 | + |
| 8 | + "cloud.google.com/go/pubsub" |
| 9 | + "github.com/ThreeDotsLabs/watermill" |
| 10 | + "github.com/ThreeDotsLabs/watermill-googlecloud/pkg/googlecloud" |
| 11 | + "github.com/ThreeDotsLabs/watermill-http/v2/pkg/http" |
| 12 | + "github.com/ThreeDotsLabs/watermill/components/cqrs" |
| 13 | + "github.com/ThreeDotsLabs/watermill/message" |
| 14 | + "github.com/ThreeDotsLabs/watermill/message/router/middleware" |
| 15 | +) |
| 16 | + |
| 17 | +type PostViewed struct { |
| 18 | + PostID int `json:"post_id"` |
| 19 | +} |
| 20 | + |
| 21 | +type PostReactionAdded struct { |
| 22 | + PostID int `json:"post_id"` |
| 23 | + ReactionID string `json:"reaction_id"` |
| 24 | +} |
| 25 | + |
| 26 | +type PostStatsUpdated struct { |
| 27 | + PostID int `json:"post_id"` |
| 28 | + ViewsUpdated bool `json:"views_updated"` |
| 29 | + ReactionUpdated *string `json:"reaction_updated"` |
| 30 | +} |
| 31 | + |
| 32 | +type Routers struct { |
| 33 | + EventsRouter *message.Router |
| 34 | + SSERouter http.SSERouter |
| 35 | + EventBus *cqrs.EventBus |
| 36 | +} |
| 37 | + |
| 38 | +func NewRouters(cfg config, repo *Repository) (Routers, error) { |
| 39 | + logger := watermill.NewStdLogger(false, false) |
| 40 | + |
| 41 | + publisher, err := googlecloud.NewPublisher( |
| 42 | + googlecloud.PublisherConfig{ |
| 43 | + ProjectID: cfg.PubSubProjectID, |
| 44 | + }, |
| 45 | + logger, |
| 46 | + ) |
| 47 | + if err != nil { |
| 48 | + return Routers{}, err |
| 49 | + } |
| 50 | + |
| 51 | + eventBus, err := cqrs.NewEventBusWithConfig( |
| 52 | + publisher, |
| 53 | + cqrs.EventBusConfig{ |
| 54 | + GeneratePublishTopic: func(params cqrs.GenerateEventPublishTopicParams) (string, error) { |
| 55 | + return params.EventName, nil |
| 56 | + }, |
| 57 | + Marshaler: cqrs.JSONMarshaler{}, |
| 58 | + Logger: logger, |
| 59 | + }, |
| 60 | + ) |
| 61 | + if err != nil { |
| 62 | + return Routers{}, err |
| 63 | + } |
| 64 | + |
| 65 | + eventsRouter, err := message.NewRouter(message.RouterConfig{}, logger) |
| 66 | + if err != nil { |
| 67 | + return Routers{}, err |
| 68 | + } |
| 69 | + |
| 70 | + eventsRouter.AddMiddleware(middleware.Recoverer) |
| 71 | + |
| 72 | + eventProcessor, err := cqrs.NewEventProcessorWithConfig( |
| 73 | + eventsRouter, |
| 74 | + cqrs.EventProcessorConfig{ |
| 75 | + GenerateSubscribeTopic: func(params cqrs.EventProcessorGenerateSubscribeTopicParams) (string, error) { |
| 76 | + return params.EventName, nil |
| 77 | + }, |
| 78 | + SubscriberConstructor: func(params cqrs.EventProcessorSubscriberConstructorParams) (message.Subscriber, error) { |
| 79 | + return googlecloud.NewSubscriber( |
| 80 | + googlecloud.SubscriberConfig{ |
| 81 | + ProjectID: cfg.PubSubProjectID, |
| 82 | + GenerateSubscriptionName: func(topic string) string { |
| 83 | + return fmt.Sprintf("%v_%v", topic, params.HandlerName) |
| 84 | + }, |
| 85 | + }, |
| 86 | + logger, |
| 87 | + ) |
| 88 | + }, |
| 89 | + Marshaler: cqrs.JSONMarshaler{}, |
| 90 | + Logger: logger, |
| 91 | + }, |
| 92 | + ) |
| 93 | + if err != nil { |
| 94 | + return Routers{}, err |
| 95 | + } |
| 96 | + |
| 97 | + err = eventProcessor.AddHandlers( |
| 98 | + cqrs.NewEventHandler( |
| 99 | + "UpdateViews", |
| 100 | + func(ctx context.Context, event *PostViewed) error { |
| 101 | + err = repo.UpdatePost(ctx, event.PostID, func(post *Post) { |
| 102 | + post.Views++ |
| 103 | + }) |
| 104 | + if err != nil { |
| 105 | + return err |
| 106 | + } |
| 107 | + |
| 108 | + statsUpdated := PostStatsUpdated{ |
| 109 | + PostID: event.PostID, |
| 110 | + ViewsUpdated: true, |
| 111 | + } |
| 112 | + |
| 113 | + return eventBus.Publish(ctx, statsUpdated) |
| 114 | + }, |
| 115 | + ), |
| 116 | + cqrs.NewEventHandler( |
| 117 | + "UpdateReactions", |
| 118 | + func(ctx context.Context, event *PostReactionAdded) error { |
| 119 | + err := repo.UpdatePost(ctx, event.PostID, func(post *Post) { |
| 120 | + post.Reactions[event.ReactionID]++ |
| 121 | + }) |
| 122 | + if err != nil { |
| 123 | + return err |
| 124 | + } |
| 125 | + |
| 126 | + statsUpdated := PostStatsUpdated{ |
| 127 | + PostID: event.PostID, |
| 128 | + ReactionUpdated: &event.ReactionID, |
| 129 | + } |
| 130 | + |
| 131 | + return eventBus.Publish(ctx, statsUpdated) |
| 132 | + }, |
| 133 | + ), |
| 134 | + ) |
| 135 | + if err != nil { |
| 136 | + return Routers{}, err |
| 137 | + } |
| 138 | + |
| 139 | + sseSubscriber, err := googlecloud.NewSubscriber( |
| 140 | + googlecloud.SubscriberConfig{ |
| 141 | + ProjectID: cfg.PubSubProjectID, |
| 142 | + GenerateSubscriptionName: func(topic string) string { |
| 143 | + return fmt.Sprintf("%v_%v", topic, watermill.NewShortUUID()) |
| 144 | + }, |
| 145 | + SubscriptionConfig: pubsub.SubscriptionConfig{ |
| 146 | + ExpirationPolicy: time.Hour * 24, |
| 147 | + }, |
| 148 | + }, |
| 149 | + logger, |
| 150 | + ) |
| 151 | + if err != nil { |
| 152 | + return Routers{}, err |
| 153 | + } |
| 154 | + |
| 155 | + sseRouter, err := http.NewSSERouter( |
| 156 | + http.SSERouterConfig{ |
| 157 | + UpstreamSubscriber: sseSubscriber, |
| 158 | + Marshaler: http.StringSSEMarshaler{}, |
| 159 | + }, |
| 160 | + logger, |
| 161 | + ) |
| 162 | + if err != nil { |
| 163 | + return Routers{}, err |
| 164 | + } |
| 165 | + |
| 166 | + return Routers{ |
| 167 | + EventsRouter: eventsRouter, |
| 168 | + SSERouter: sseRouter, |
| 169 | + EventBus: eventBus, |
| 170 | + }, nil |
| 171 | +} |
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