[receiver/kafkametrics] Fix metrics in kafkametricsreceiver (open-telemetry#4327) (open-telemetry#23332)

Update `kafka.brokers` metric to be non-monothonic sum instead of gauge

Author: ZenoCC-Peng

.chloggen/fix-kafkametric-receiver-type.yaml

@@ -0,0 +1,20 @@
+# Use this changelog template to create an entry for release notes.
+# If your change doesn't affect end users, such as a test fix or a tooling change,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: receiver/kafkametricsreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Updates certain metrics in kafkametricsreceiver to function as non-monotonic sums.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [4327]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: Update the metric type in KafkaMetricsReceiver from "gauge" to "nonmonotonic sum".

receiver/kafkametricsreceiver/broker_scraper_test.go

@@ -106,7 +106,7 @@ func TestBrokerScraper_scrape(t *testing.T) {
 	assert.NoError(t, err)
 	expectedDp := int64(len(testBrokers))
 	receivedMetrics := md.ResourceMetrics().At(0).ScopeMetrics().At(0).Metrics().At(0)
-	receivedDp := receivedMetrics.Gauge().DataPoints().At(0).IntValue()
+	receivedDp := receivedMetrics.Sum().DataPoints().At(0).IntValue()
 	assert.Equal(t, expectedDp, receivedDp)
 }
 

receiver/kafkametricsreceiver/documentation.md

@@ -16,9 +16,9 @@ metrics:
 
 Number of brokers in the cluster.
 
-| Unit | Metric Type | Value Type |
-| ---- | ----------- | ---------- |
-| {brokers} | Gauge | Int |
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {brokers} | Sum | Int | Delta | false |
 
 ### kafka.consumer_group.lag
 

receiver/kafkametricsreceiver/internal/metadata/generated_metrics.go

@@ -18,14 +18,16 @@ attributes:
     type: string
 
 metrics:
-#  brokers scraper
+  #  brokers scraper
   kafka.brokers:
     enabled: true
     description: Number of brokers in the cluster.
     unit: "{brokers}"
-    gauge:
+    sum:
+      monotonic: false
       value_type: int
-#  topics scraper
+      aggregation: delta
+  #  topics scraper
   kafka.topic.partitions:
     enabled: true
     description: Number of partitions in topic.
@@ -61,7 +63,7 @@ metrics:
     gauge:
       value_type: int
     attributes: [topic, partition]
-#  consumers scraper
+  #  consumers scraper
   kafka.consumer_group.members:
     enabled: true
     description: Count of members in the consumer group
@@ -96,4 +98,4 @@ metrics:
     unit: 1
     gauge:
       value_type: int
-    attributes: [group, topic]
+    attributes: [group, topic]

receiver/kafkametricsreceiver/internal/metadata/generated_metrics_test.go

@@ -3,7 +3,8 @@ resourceMetrics:
     scopeMetrics:
       - metrics:
           - description: Number of brokers in the cluster.
-            gauge:
+            sum:
+              aggregationTemporality: 1
               dataPoints:
                 - asInt: "1"
                   startTimeUnixNano: "1685063120199110000"