From d8bb21ab1bcfeb7e8436a7c7c703719a1f61a270 Mon Sep 17 00:00:00 2001
From: Tyler Yahn <codingalias@gmail.com>
Date: Fri, 16 Sep 2022 13:29:25 -0700
Subject: [PATCH] Fix prom exporter panic on invalid metric

Resolves #3180
---
 exporters/prometheus/exporter.go      |  2 ++
 exporters/prometheus/exporter_test.go | 28 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/exporters/prometheus/exporter.go b/exporters/prometheus/exporter.go
index 8527b1b5025..e210728c482 100644
--- a/exporters/prometheus/exporter.go
+++ b/exporters/prometheus/exporter.go
@@ -90,12 +90,14 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 			m, err := prometheus.NewConstHistogram(metricData.description, metricData.histogramCount, metricData.histogramSum, metricData.histogramBuckets, metricData.attributeValues...)
 			if err != nil {
 				otel.Handle(err)
+				continue
 			}
 			ch <- m
 		} else {
 			m, err := prometheus.NewConstMetric(metricData.description, metricData.valueType, metricData.value, metricData.attributeValues...)
 			if err != nil {
 				otel.Handle(err)
+				continue
 			}
 			ch <- m
 		}
diff --git a/exporters/prometheus/exporter_test.go b/exporters/prometheus/exporter_test.go
index aaf029e2021..173df4b98a8 100644
--- a/exporters/prometheus/exporter_test.go
+++ b/exporters/prometheus/exporter_test.go
@@ -103,6 +103,34 @@ func TestPrometheusExporter(t *testing.T) {
 				counter.Add(ctx, 9, attrs...)
 			},
 		},
+		{
+			name:         "invalid instruments are dropped",
+			expectedFile: "testdata/gauge.txt",
+			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
+				attrs := []attribute.KeyValue{
+					attribute.Key("A").String("B"),
+					attribute.Key("C").String("D"),
+				}
+				// Valid.
+				gauge, err := meter.SyncFloat64().UpDownCounter("bar", instrument.WithDescription("a fun little gauge"))
+				require.NoError(t, err)
+				gauge.Add(ctx, 100, attrs...)
+				gauge.Add(ctx, -25, attrs...)
+
+				// Invalid, should be dropped.
+				gauge, err = meter.SyncFloat64().UpDownCounter("invalid.gauge.name")
+				require.NoError(t, err)
+				gauge.Add(ctx, 100, attrs...)
+
+				counter, err := meter.SyncFloat64().Counter("invalid.counter.name")
+				require.NoError(t, err)
+				counter.Add(ctx, 100, attrs...)
+
+				histogram, err := meter.SyncFloat64().Histogram("invalid.hist.name")
+				require.NoError(t, err)
+				histogram.Record(ctx, 23, attrs...)
+			},
+		},
 	}
 
 	for _, tc := range testCases {