Expose Hystrix stream as Prometheus data

This module has a peer dependency on prom-client. Currently, version 3-5 are supported.

This module exports a single function, taking a Stream of Hystrix data, and returning a Subscription of the same data, which can be unsubscribed if you so which.

brakes exposes Hystrix data as a stream.

import { getGlobalStats } from 'brakes';
import prometheusHystrix from 'prometheus-hystrix';
import prometheusRegister from 'prom-client/lib/register';

prometheusHystrix(getGlobalStats().getHystrixStream());

setInterval(() => {
  console.log(prometheusRegister.metrics());
}, 500)

This module exposes 17 metrics, all using the name of the HystrixCommand as the label:

1. hystrix_errors_total: Total number of times the breaker has errored
2. hystrix_requests_total: Total number of requests made to the breaker
3. hystrix_collapsed_requests_total: Total number of times a requests has been collapsed.
4. hystrix_exceptions_thrown_total: Total number of times an exception has been thrown.
5. hystrix_failures_total: Total number of times a call has failed.
6. hystrix_fallback_failures_total: Total number of times a fallback has failed.
7. hystrix_fallback_rejections_total: Total number of times a fallback has rejected.
8. hystrix_fallback_successes_total: Total number of times a fallback has been successful.
9. hystrix_responses_from_cache_total: Total number of times a response has been returned from the cache.
10. hystrix_semaphore_rejections_total: Total number of times a request failed because of empty semaphore.
11. hystrix_short_circuits_total: Total number of times a request short circuited.
12. hystrix_successes_total: Total number of times a request succeeded.
13. hystrix_thread_pool_rejections_total: Total number of times a the thread pool rejected.
14. hystrix_timeouts_total: Total number of times a request timed out.
15. hystrix_current_concurrent_executions_total: Total number of requests going concurrently.
16. hystrix_latency_execute_mean: Mean latency of all executions.
17. hystrix_latency_total_mean: Mean latency of all requests.

There are currently no metrics for the calculated percentiles latencyExecute and latencyTotal.