Fix tnt_cartridge_failover_trigger metric name (#396)

Author: yngvar-antonsson

CHANGELOG.md

@@ -15,7 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Label `thread` for per thread reporting net statistics metrics.
-- `tnt_cartridge_failover_trigger` metric
+- `tnt_cartridge_failover_trigger_total` metric
 - New synchro and election metrics:
   - `tnt_synchro_queue_owner`
   - `tnt_synchro_queue_term`

doc/monitoring/metrics_reference.rst

@@ -411,7 +411,7 @@ Cartridge
                 *   ``max`` -- difference with the fastest clock (always positive),
                 *   ``min`` -- difference with the slowest clock (always negative).
 
-        *   -   ``tnt_cartridge_failover_trigger``
+        *   -   ``tnt_cartridge_failover_trigger_total``
             -   Count of failover triggers in cluster.
 
 ..  _metrics-reference-luajit:

metrics/cartridge/failover.lua

@@ -16,7 +16,7 @@ local function update()
     if trigger_cnt ~= nil then
         collectors_list.trigger_cnt =
             utils.set_counter(
-                'cartridge_failover_trigger',
+                'cartridge_failover_trigger_total',
                 'Count of Cartridge Failover triggers',
                 trigger_cnt
             )

test/integration/cartridge_metrics_test.lua

@@ -137,7 +137,7 @@ g.test_failover = function()
 
     helpers.retrying({timeout = 30}, function()
         local resp = g.cluster:server('replica'):http_request('get', '/metrics')
-        local failover_trigger_cnt = utils.find_metric('tnt_cartridge_failover_trigger', resp.json)
+        local failover_trigger_cnt = utils.find_metric('tnt_cartridge_failover_trigger_total', resp.json)
         t.assert_equals(failover_trigger_cnt[1].value, 1)
     end)