feat(mixin-utils): add ncHistogramCountIncrease (#1560)

* feat(mixin-utils): add ncHistogramCountIncrease

Based on ncHistogramCountRate, but it cannot use the
recording rule, because that does `rate` and not `incease`.

Signed-off-by: György Krajcsovits <[email protected]>

* rename local vars

Signed-off-by: György Krajcsovits <[email protected]>

---------

Signed-off-by: György Krajcsovits <[email protected]>

Author: krajorama

mixin-utils/test/test_native-classic-histogram.libsonnet

@@ -238,3 +238,23 @@ test.new(std.thisFile)
     }
   )
 )
++ test.case.new(
+  name='histogram count increase',
+  test=test.expect.eq(
+    actual=utils.ncHistogramCountIncrease('request_duration_seconds', 'cluster="cluster1", job="job1"'),
+    expected={
+      classic: 'increase(request_duration_seconds_count{cluster="cluster1", job="job1"}[$__rate_interval])',
+      native: 'histogram_count(increase(request_duration_seconds{cluster="cluster1", job="job1"}[$__rate_interval]))',
+    }
+  )
+)
++ test.case.new(
+  name='histogram count increase with rate interval',
+  test=test.expect.eq(
+    actual=utils.ncHistogramCountIncrease('request_duration_seconds', 'cluster="cluster1", job="job1"', rate_interval='5m'),
+    expected={
+      classic: 'increase(request_duration_seconds_count{cluster="cluster1", job="job1"}[5m])',
+      native: 'histogram_count(increase(request_duration_seconds{cluster="cluster1", job="job1"}[5m]))',
+    }
+  )
+)

mixin-utils/utils.libsonnet

@@ -94,6 +94,29 @@ local g = import 'grafana-builder/grafana.libsonnet';
       },
     },
 
+  // The ncHistogramCountIncrease (native classic histogram count rate) function is
+  // used to calculate the histogram increase of count from native histograms or
+  // classic histograms. Metric name should be provided without _count suffix.
+  ncHistogramCountIncrease(metric, selector, rate_interval='$__rate_interval')::
+    local increaseOpen = 'increase(';
+    local increaseClose = '[%s])' % rate_interval;
+    {
+      classic: '%(increaseOpen)s%(metric)s_count{%(selector)s}%(increaseClose)s' % {
+        metric: metric,
+        rateInterval: rate_interval,
+        increaseOpen: increaseOpen,
+        increaseClose: increaseClose,
+        selector: selector,
+      },
+      native: 'histogram_count(%(increaseOpen)s%(metric)s{%(selector)s}%(increaseClose)s)' % {
+        metric: metric,
+        rateInterval: rate_interval,
+        increaseOpen: increaseOpen,
+        increaseClose: increaseClose,
+        selector: selector,
+      },
+    },
+
   // TODO(krajorama) Switch to histogram_avg function for native histograms later.
   // ncHistogramAverageRate (native classic histogram average rate) function is
   // used to calculate the histogram average rate from native histograms or