From 28d0f96bbcc405c7c70d065f05c4719685017084 Mon Sep 17 00:00:00 2001
From: Ratan Boddu <ratanboddu@INFPUMAC16.local>
Date: Wed, 22 May 2019 19:46:11 +0530
Subject: [PATCH] Added _delta in Histogram and Summary

Signed-off-by: Ratan Boddu <ratan.boddu@lntinfotech.com>
---
 prometheus_client/metrics.py         | 10 +++++++++-
 tests/openmetrics/test_exposition.py |  2 ++
 tests/test_exposition.py             |  2 ++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/prometheus_client/metrics.py b/prometheus_client/metrics.py
index b7c5e5a4..b4fd1534 100644
--- a/prometheus_client/metrics.py
+++ b/prometheus_client/metrics.py
@@ -412,12 +412,15 @@ def _metric_init(self):
         self._count = values.ValueClass(self._type, self._name, self._name + '_count', self._labelnames,
                                         self._labelvalues)
         self._sum = values.ValueClass(self._type, self._name, self._name + '_sum', self._labelnames, self._labelvalues)
+        self._delta = 0.0
         self._created = time.time()
 
+
     def observe(self, amount):
         """Observe the given amount."""
         self._count.inc(1)
         self._sum.inc(amount)
+        self._delta = amount
 
     def time(self):
         """Time a block of code or function, and observe the duration in seconds.
@@ -430,7 +433,8 @@ def _child_samples(self):
         return (
             ('_count', {}, self._count.get()),
             ('_sum', {}, self._sum.get()),
-            ('_created', {}, self._created))
+            ('_created', {}, self._created),
+            ('_delta', {}, self._delta))
 
 
 class Histogram(MetricWrapperBase):
@@ -511,6 +515,7 @@ def _prepare_buckets(self, buckets):
     def _metric_init(self):
         self._buckets = []
         self._created = time.time()
+        self._delta = 0.0
         bucket_labelnames = self._labelnames + ('le',)
         self._sum = values.ValueClass(self._type, self._name, self._name + '_sum', self._labelnames, self._labelvalues)
         for b in self._upper_bounds:
@@ -525,6 +530,7 @@ def _metric_init(self):
     def observe(self, amount):
         """Observe the given amount."""
         self._sum.inc(amount)
+        self._delta = amount
         for i, bound in enumerate(self._upper_bounds):
             if amount <= bound:
                 self._buckets[i].inc(1)
@@ -546,6 +552,8 @@ def _child_samples(self):
         samples.append(('_count', {}, acc))
         samples.append(('_sum', {}, self._sum.get()))
         samples.append(('_created', {}, self._created))
+        samples.append(('_delta', {}, self._delta))
+
         return tuple(samples)
 
 
diff --git a/tests/openmetrics/test_exposition.py b/tests/openmetrics/test_exposition.py
index 502a45e0..29d47653 100644
--- a/tests/openmetrics/test_exposition.py
+++ b/tests/openmetrics/test_exposition.py
@@ -61,6 +61,7 @@ def test_summary(self):
 ss_count{a="c",b="d"} 1.0
 ss_sum{a="c",b="d"} 17.0
 ss_created{a="c",b="d"} 123.456
+ss_delta{a="c",b="d"} 17.0
 # EOF
 """, generate_latest(self.registry))
 
@@ -88,6 +89,7 @@ def test_histogram(self):
 hh_count 1.0
 hh_sum 0.05
 hh_created 123.456
+hh_delta 0.05
 # EOF
 """, generate_latest(self.registry))
 
diff --git a/tests/test_exposition.py b/tests/test_exposition.py
index 00f39b47..f3db768d 100644
--- a/tests/test_exposition.py
+++ b/tests/test_exposition.py
@@ -82,6 +82,7 @@ def test_summary(self):
 # TYPE ss summary
 ss_count{a="c",b="d"} 1.0
 ss_sum{a="c",b="d"} 17.0
+ss_delta{a="c",b="d"} 17.0
 # TYPE ss_created gauge
 ss_created{a="c",b="d"} 123.456
 """, generate_latest(self.registry))
@@ -109,6 +110,7 @@ def test_histogram(self):
 hh_bucket{le="+Inf"} 1.0
 hh_count 1.0
 hh_sum 0.05
+hh_delta 0.05
 # TYPE hh_created gauge
 hh_created 123.456
 """, generate_latest(self.registry))