80 lines
2.6 KiB
Go
80 lines
2.6 KiB
Go
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/*
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Package hystrix is a latency and fault tolerance library designed to isolate
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points of access to remote systems, services and 3rd party libraries, stop
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cascading failure and enable resilience in complex distributed systems where
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failure is inevitable.
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Based on the java project of the same name, by Netflix. https://github.com/Netflix/Hystrix
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Execute code as a Hystrix command
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Define your application logic which relies on external systems, passing your function to Go. When that system is healthy this will be the only thing which executes.
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hystrix.Go("my_command", func() error {
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// talk to other services
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return nil
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}, nil)
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Defining fallback behavior
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If you want code to execute during a service outage, pass in a second function to Go. Ideally, the logic here will allow your application to gracefully handle external services being unavailable.
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This triggers when your code returns an error, or whenever it is unable to complete based on a variety of health checks https://github.com/Netflix/Hystrix/wiki/How-it-Works.
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hystrix.Go("my_command", func() error {
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// talk to other services
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return nil
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}, func(err error) error {
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// do this when services are down
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return nil
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})
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Waiting for output
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Calling Go is like launching a goroutine, except you receive a channel of errors you can choose to monitor.
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output := make(chan bool, 1)
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errors := hystrix.Go("my_command", func() error {
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// talk to other services
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output <- true
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return nil
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}, nil)
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select {
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case out := <-output:
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// success
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case err := <-errors:
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// failure
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}
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Synchronous API
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Since calling a command and immediately waiting for it to finish is a common pattern, a synchronous API is available with the Do function which returns a single error.
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err := hystrix.Do("my_command", func() error {
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// talk to other services
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return nil
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}, nil)
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Configure settings
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During application boot, you can call ConfigureCommand to tweak the settings for each command.
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hystrix.ConfigureCommand("my_command", hystrix.CommandConfig{
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Timeout: 1000,
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MaxConcurrentRequests: 100,
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ErrorPercentThreshold: 25,
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})
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You can also use Configure which accepts a map[string]CommandConfig.
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Enable dashboard metrics
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In your main.go, register the event stream HTTP handler on a port and launch it in a goroutine. Once you configure turbine for your Hystrix Dashboard https://github.com/Netflix/Hystrix/tree/master/hystrix-dashboard to start streaming events, your commands will automatically begin appearing.
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hystrixStreamHandler := hystrix.NewStreamHandler()
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hystrixStreamHandler.Start()
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go http.ListenAndServe(net.JoinHostPort("", "81"), hystrixStreamHandler)
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*/
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package hystrix
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