dahernan / gohystrix Goto Github PK

Just for discussion: I find it "ugly" to have to define a Name() and Group() function.

I played around with a few concepts, and I came up with the following solution:
The command only has one Describe() function, which returns a goHystrix.CommandOptions containing all necessary values (name, group, threadgroup, isolation level, etc.). Using the builder pattern, this function could be very small, but descriptive.

An example, how this could look like can be seen at this gist: https://gist.github.com/ZeissS/9766129

What do you think?

Hi,

I can only find ErrorPercetageThreshold on the README.md and nothing on the code itself, only ErrorsThreshold.

I'm thinking of moving the methods Timeout(), Name(), and Group() to CommandOptions and keep the Interface simple.

You can pass the options to the NewCommand as following

NewCommand(interface, commandOptions, circuitOptions)

@zeisss any advice??

In the NetFlix Hystrix Java implementation an open circuit breaker will reset itself (i.e., close) after circuitBreaker.sleepWindowInMilliseconds. In goHystrix an open circuit breaker will only reset itself if no requests are received during the NumberOfSecondsToStore interval. The NumberOfSecondsToStore interval is important in defining the rolling window of metrics but it's not enough. A circuit breaker implementation also needs to provide a way for the breaker to periodically allow requests to go through in order to see if the failed dependency has resolved, i.e., it needs to support a 3rd state - half-open.

Do you have any plans to provide a half-open state similar to NetFlix's Hystrix? If not, would you accept a pull request to implement it?

I do like goHystrix's support for access to detailed metrics!

Put a cancellation channel or context like this http://blog.golang.org/context, so you can is some way to send a cancellacion signal to go routines

cancel the go routine when a timeout is reached

Given I have an application which uses goHystric to secure it backend calls, I would like to expose the collected statistics to an external service automatically, e.g. statsd/graphite.

Currently, Circuits() already provides me with an way to access existing CircuitBreakers, if I have the names. With this I can access the metrics and thus via Stats() the samples values.

It would be nicer to have some operation to iterate over all existing circuitbreakers, to automatically expose them. This could as simple as having an Each(handler func(group, name string, breaker *CircuitBreaker) function, which loops over everything.

Currently Executor#Execute() only calls Run() OR Fallback() depending on the CircuitBreaker. The original Hystrix implementation also calls the fallback in case of a timeout or exception in Run() as well.

See the flowchart at https://github.com/Netflix/Hystrix/wiki/How-it-Works#Flow

Hi,

I just stumbled upon the original netflix article and was searching, whether someone did something similar for Go. And there you are :) Thanks!

I was wondering, why you made the Fallback() function required? I think one could just define an aditional interface, move the fallback function there and check (on error in Run()), if the command can be converted to the Fallback interface.

Just a thought I had while reading your README (I haven't actually tried anything yet).

Thanks again!

P.S.: The same could be done for the Timeout. Just default to something like 5 seconds.

Add a way to define a command with a function (like http.HandleFunc works :)

Can you add a LICENSE? :)

Follow this pattern
https://rogpeppe.wordpress.com/2014/04/23/some-suggested-rules-for-generating-good-errors-in-go/

http://godoc.org/github.com/juju/errgo

With the JSON of all the circuits is possible to render a dashboard similar to https://raw.github.com/wiki/Netflix/Hystrix/images/hystrix-dashboard-single-row.png