This change replaces the deprecated InstrumentHandler function by
the equivalent functions from the promhttp package.
The following metrics are removed:
* http_request_duration_microseconds (Summary).
* http_request_size_bytes (Summary).
* http_requests_total (Counter).
And the following metrics are added instead:
* alertmanager_http_request_duration_seconds (Histogram).
* alertmanager_http_response_size_bytes (Histogram).
* promhttp_metric_handler_requests_in_flight (Gauge).
* promhttp_metric_handler_requests_total (Counter).
* Wait for the gossip to settle before sending notifications
See #1209 for details.
As an heuristic for mesh readyness, try to see if
the mesh looks stable (the number of peers isn't changing too much).
This implementation always mark the altermanager as ready after a maximum of 60s.
This adds one new flags to control this behavior:
```
--cluster.settle-timeout=60s mesh settling timeout. Do not wait more than this duration on startup.
```
It also adds `/-/ready` which always return 200 (in order to make it clear
that we are ready as soon as we can receive requests).
The mesh status is exposed in `/api/v1/status` and visible on `/#/status`.
* cluster: fix typos and base interval on gossipInterval
The commit [1] introduced the `cache-control` header field with the value
`no-cache`. This enforces any cache to revalidate. Apparently this does
not prohibit *FireFox* from caching the assets. `no-cache, no-store,
must-revalidate` does by prohibiting to even save anything of the
request.
[1] c3850708c1
By passing "-modtime 1" flag into go-bindata command it uses the same
unix timestamp (1) for every file in the fake filesystem. Thereby every
execution of "make assets" results in the same asset outputs if the
inputs were the same. This forces us to set the "Cache-Control"
attribute to "no-cache".
* Including glue between Alertmanager server and Elm UI.
* Rebuilding assets (ui/bindata.go).
* Exact commit: 'bd78de6b16bcefaacf4229304d439b33aa09cc72'
* Subdirectory: ui/app