forked from looplab/eventhorizon
/
eventbus.go
54 lines (45 loc) · 1.69 KB
/
eventbus.go
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// Copyright (c) 2020 - The Event Horizon authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package tracing
import (
"context"
eh "github.com/gingfrederik/eventhorizon"
)
// EventBus is an event bus wrapper that adds tracing.
type EventBus struct {
eh.EventBus
h eh.EventHandler
}
// NewEventBus creates a EventBus.
func NewEventBus(eventBus eh.EventBus) *EventBus {
return &EventBus{
EventBus: eventBus,
// Wrap the eh.EventHandler part of the bus with tracing middleware,
// set as producer to set the correct tags.
h: eh.UseEventHandlerMiddleware(eventBus, NewEventHandlerMiddleware()),
}
}
// HandleEvent implements the HandleEvent method of the eventhorizon.EventHandler interface.
func (b *EventBus) HandleEvent(ctx context.Context, event eh.Event) error {
return b.h.HandleEvent(ctx, event)
}
// AddHandler implements the AddHandler method of the eventhorizon.EventBus interface.
func (b *EventBus) AddHandler(ctx context.Context, m eh.EventMatcher, h eh.EventHandler) error {
if h == nil {
return eh.ErrMissingHandler
}
// Wrap the handlers in tracing middleware.
h = eh.UseEventHandlerMiddleware(h, NewEventHandlerMiddleware())
return b.EventBus.AddHandler(ctx, m, h)
}