38 lines
1.1 KiB
Go
38 lines
1.1 KiB
Go
package middleware
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import (
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"github.com/ThreeDotsLabs/watermill/message"
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"github.com/sony/gobreaker"
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)
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// CircuitBreaker is a middleware that wraps the handler in a circuit breaker.
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// Based on the configuration, the circuit breaker will fail fast if the handler keeps returning errors.
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// This is useful for preventing cascading failures.
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type CircuitBreaker struct {
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cb *gobreaker.CircuitBreaker
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}
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// NewCircuitBreaker returns a new CircuitBreaker middleware.
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// Refer to the gobreaker documentation for the available settings.
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func NewCircuitBreaker(settings gobreaker.Settings) CircuitBreaker {
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return CircuitBreaker{
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cb: gobreaker.NewCircuitBreaker(settings),
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}
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}
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// Middleware returns the CircuitBreaker middleware.
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func (c CircuitBreaker) Middleware(h message.HandlerFunc) message.HandlerFunc {
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return func(msg *message.Message) ([]*message.Message, error) {
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out, err := c.cb.Execute(func() (interface{}, error) {
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return h(msg)
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})
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var result []*message.Message
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if out != nil {
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result = out.([]*message.Message)
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}
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return result, err
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}
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}
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