Hi, i would like to implement a circuit breaker functionality with the help of HAProxy.
For example, if the average response time of the http requests of a backend server is above a certain threshold in the last x seconds, trip the circuit breaker for a period of x seconds (respond with 503 and/or show error page etc.). After the period has expired, close the circuit and forward requests to the server as normal. The same logic should be applied to http response status (if a defined status (500) is above a ratio of 1% of all requests). I want to use HAProxy for this task to not need to implement this functionality/pattern in every single application or (micro)service. I'm aware of "observe layer7" or "http_err_rate" fetch, but these doesn't fulfill the requirements. At the moment i haven't found a way to implement this with HAProxy built-in functions. I can think of a Lua solution, but i'm not sure if this is possible. I need to save the backend response time of every transaction in a shared memory segment (i want to avoid Redis if possible). Then read from this segment, implement a sliding window and decide based on calculations+thresholds if the circuit breaker should be tripped. A similar logic applies to http response status. Any ideas on this? Best Regards / Mit freundlichen Grueßen _____________ Bjoern
