From f5f3b701032cd289e503da7d20a95019d4b1c334 Mon Sep 17 00:00:00 2001
From: Paul Fairless <paul.fairless@gmail.com>
Date: Fri, 14 Aug 2020 13:48:12 +0100
Subject: [PATCH] feat: add prom export for VALUE_RECORDER, SUM_OBSERVER &
 UP_DOWN_SUM_OBSERVER

---
 .../src/prometheus.ts                         |   9 +-
 .../test/prometheus.test.ts                   | 116 +++++++++++++++++-
 2 files changed, 121 insertions(+), 4 deletions(-)

diff --git a/packages/opentelemetry-exporter-prometheus/src/prometheus.ts b/packages/opentelemetry-exporter-prometheus/src/prometheus.ts
index af0c551dba..e58499c40b 100644
--- a/packages/opentelemetry-exporter-prometheus/src/prometheus.ts
+++ b/packages/opentelemetry-exporter-prometheus/src/prometheus.ts
@@ -208,9 +208,12 @@ export class PrometheusExporter implements MetricExporter {
         return new Counter(metricObject);
       case MetricKind.UP_DOWN_COUNTER:
         return new Gauge(metricObject);
-      // case MetricKind.VALUE_RECORDER:
-      // case MetricKind.SUM_OBSERVER:
-      // case MetricKind.UP_DOWN_SUM_OBSERVER:
+      case MetricKind.VALUE_RECORDER:
+        return new Gauge(metricObject);
+      case MetricKind.SUM_OBSERVER:
+        return new Counter(metricObject);
+      case MetricKind.UP_DOWN_SUM_OBSERVER:
+        return new Gauge(metricObject);
       case MetricKind.VALUE_OBSERVER:
         return new Gauge(metricObject);
       default:
diff --git a/packages/opentelemetry-exporter-prometheus/test/prometheus.test.ts b/packages/opentelemetry-exporter-prometheus/test/prometheus.test.ts
index 12acad6669..9ff530cea0 100644
--- a/packages/opentelemetry-exporter-prometheus/test/prometheus.test.ts
+++ b/packages/opentelemetry-exporter-prometheus/test/prometheus.test.ts
@@ -417,7 +417,121 @@ describe('PrometheusExporter', () => {
         });
       });
     });
-  });
+
+    it('should export a SumObserver as a counter', done => {
+      function getValue() {
+        return 20;
+      }
+
+      meter.createSumObserver('sum_observer', {
+        description: 'a test description',
+      },
+      (observerResult: ObserverResult) => {
+        observerResult.observe(getValue(), {
+          key1: "labelValue1",
+        })
+      });
+
+      meter.collect().then(() => {
+        exporter.export(meter.getBatcher().checkPointSet(), () => {
+          http
+          .get('http://localhost:9464/metrics', res => {
+            res.on('data', chunk => {
+              const body = chunk.toString();
+              const lines = body.split('\n');
+
+              assert.deepStrictEqual(lines, [
+                '# HELP sum_observer a test description',
+                '# TYPE sum_observer counter',
+                `sum_observer{key1="labelValue1"} 20 ${mockedTimeMS}`,
+                '',
+              ]);
+            });
+
+            done();
+          })
+          .on('error', errorHandler(done));
+        });
+      });
+    });
+
+    it('should export a UpDownSumObserver as a gauge', done => {
+      function getValue() {
+        return 20;
+      }
+
+      meter.createUpDownSumObserver('updown_observer', {
+        description: 'a test description',
+      },
+      (observerResult: ObserverResult) => {
+        observerResult.observe(getValue(), {
+          key1: "labelValue1",
+        })
+      });
+
+      meter.collect().then(() => {
+        exporter.export(meter.getBatcher().checkPointSet(), () => {
+          http
+          .get('http://localhost:9464/metrics', res => {
+            res.on('data', chunk => {
+              const body = chunk.toString();
+              const lines = body.split('\n');
+
+              assert.deepStrictEqual(lines, [
+                '# HELP updown_observer a test description',
+                '# TYPE updown_observer gauge',
+                'updown_observer{key1="labelValue1"} 20',
+                '',
+              ]);
+            });
+
+            done();
+          })
+          .on('error', errorHandler(done));
+        });
+      });
+    });
+
+    it('should export a ValueRecorder as a guage', done => {
+
+      const valueRecorder = meter.createValueRecorder('value_recorder', {
+          description: 'a test description',
+      });
+
+      valueRecorder.bind({ key1: 'labelValue1' }).record(20);
+
+
+      meter.collect().then(() => {
+        exporter.export(meter.getBatcher().checkPointSet(), () => {
+          http
+          .get('http://localhost:9464/metrics', res => {
+            res.on('data', chunk => {
+
+              const body = chunk.toString();
+              const lines = body.split('\n');
+
+              assert.strictEqual(
+                lines[0],
+                '# HELP value_recorder a test description'
+              );
+              assert.strictEqual(lines[1], '# TYPE value_recorder gauge');
+
+              const line3 = lines[2].split(' ');
+              assert.strictEqual(
+                line3[0],
+                'value_recorder{key1="labelValue1"}'
+              );
+              assert.equal(line3[1],  20);
+
+              done();
+            });
+          })
+          .on('error', errorHandler(done));
+        });
+      });
+    });
+
+  }); 
 
   describe('configuration', () => {
     let meter: Meter;