Merge branch 'main' into main

Author: Ignacio Bonafonte

Examples/Prometheus Sample/main.swift

@@ -37,6 +37,9 @@ var meter = meterProvider.get(instrumentationName: "MyMeter")
 var testCounter = meter.createIntCounter(name: "MyCounter")
 var testMeasure = meter.createIntMeasure(name: "MyMeasure")
 
+let boundaries: Array<Int> = [5, 10, 25]
+var testHistogram = meter.createIntHistogram(name: "MyHistogram", explicitBoundaries: boundaries, absolute: true)
+
 var testObserver = meter.createIntObserver(name: "MyObservation") { observer in
     var taskInfo = mach_task_basic_info()
     var count = mach_msg_type_number_t(MemoryLayout<mach_task_basic_info>.size) / 4
@@ -60,6 +63,11 @@ while counter < 3000 {
     testMeasure.record(value: 500, labelset: meter.getLabelSet(labels: labels1))
     testMeasure.record(value: 5, labelset: meter.getLabelSet(labels: labels1))
     testMeasure.record(value: 750, labelset: meter.getLabelSet(labels: labels1))
+
+    testHistogram.record(value: 8, labelset: meter.getLabelSet(labels: labels1))
+    testHistogram.record(value: 20, labelset: meter.getLabelSet(labels: labels1))
+    testHistogram.record(value: 30, labelset: meter.getLabelSet(labels: labels1))
+
     counter += 1
     sleep(1)
 }

Sources/Exporters/Prometheus/PrometheusExporterExtensions.swift

@@ -14,6 +14,11 @@ public enum PrometheusExporterExtensions {
     static let prometheusSummaryQuantileLabelName = "quantile"
     static let prometheusSummaryQuantileLabelValueForMin = "0"
     static let prometheusSummaryQuantileLabelValueForMax = "1"
+    static let prometheusHistogramType = "histogram"
+    static let prometheusHistogramSumPostFix = "_sum"
+    static let prometheusHistogramCountPostFix = "_count"
+    static let prometheusHistogramBucketPostFix = "_bucket"
+    static let prometheusHistogramLeLabelName = "le"
 
     static func writeMetricsCollection(exporter: PrometheusExporter) -> String {
         var output = ""
@@ -45,8 +50,20 @@ public enum PrometheusExporterExtensions {
                     let min = summary.min
                     let max = summary.max
                     output += PrometheusExporterExtensions.writeSummary(prometheusMetric: prometheusMetric, timeStamp: now, labels: labels, metricName: metric.name, sum: Double(sum), count: count, min: Double(min), max: Double(max))
-                case .intHistogram, .doubleHistogram:
-                    break
+                case .intHistogram:
+                    let histogram = metricData as! HistogramData<Int>
+                    let count = histogram.count
+                    let sum = histogram.sum
+                    let bucketsBoundaries = histogram.buckets.boundaries.map{Double($0)}
+                    let bucketsCounts = histogram.buckets.counts
+                    output += PrometheusExporterExtensions.writeHistogram(prometheusMetric: prometheusMetric, timeStamp: now, labels: labels, metricName: metric.name, sum: Double(sum), count: count, bucketsBoundaries: bucketsBoundaries, bucketsCounts: bucketsCounts)
+                case .doubleHistogram:
+                    let histogram = metricData as! HistogramData<Double>
+                    let count = histogram.count
+                    let sum = histogram.sum
+                    let bucketsBoundaries = histogram.buckets.boundaries
+                    let bucketsCounts = histogram.buckets.counts
+                    output += PrometheusExporterExtensions.writeHistogram(prometheusMetric: prometheusMetric, timeStamp: now, labels: labels, metricName: metric.name, sum: Double(sum), count: count, bucketsBoundaries: bucketsBoundaries, bucketsCounts: bucketsCounts)
                 }
             }
         }
@@ -79,4 +96,24 @@ public enum PrometheusExporterExtensions {
         }
         return prometheusMetric.write(timeStamp: timeStamp)
     }
+
+    private static func writeHistogram(prometheusMetric: PrometheusMetric, timeStamp: String, labels: [String: String], metricName: String, sum: Double, count: Int, bucketsBoundaries: Array<Double>, bucketsCounts: Array<Int>) -> String {
+        var prometheusMetric = prometheusMetric
+        prometheusMetric.type = prometheusHistogramType
+        labels.forEach {
+            prometheusMetric.values.append(PrometheusValue(name: metricName + prometheusHistogramSumPostFix, labels: [$0.key: $0.value], value: sum))
+            prometheusMetric.values.append(PrometheusValue(name: metricName + prometheusHistogramCountPostFix, labels: [$0.key: $0.value], value: Double(count)))
+            for i in 0..<bucketsBoundaries.count {
+                prometheusMetric.values.append(PrometheusValue(name: metricName,
+                                                               labels: [$0.key: $0.value,
+                                                                        prometheusHistogramLeLabelName: String(format:"%f", bucketsBoundaries[i])],
+                                                               value: Double(bucketsCounts[i])))
+            }
+            prometheusMetric.values.append(PrometheusValue(name: metricName,
+                                                           labels: [$0.key: $0.value,
+                                                                    prometheusHistogramLeLabelName: "+Inf"],
+                                                           value: Double(bucketsCounts[bucketsBoundaries.count])))
+        }
+        return prometheusMetric.write(timeStamp: timeStamp)
+    }
 }

Tests/ExportersTests/Prometheus/PrometheusExporterTests.swift

@@ -68,8 +68,11 @@ class PrometheusExporterTests: XCTestCase {
 
         let testCounter = meter.createIntCounter(name: "testCounter")
         let testMeasure = meter.createIntMeasure(name: "testMeasure")
+        let boundaries: Array<Int> = [5, 10, 25]
+        var testHistogram = meter.createIntHistogram(name: "testHistogram", explicitBoundaries: boundaries, absolute: true)
         let labels1 = ["dim1": "value1", "dim2": "value1"]
         let labels2 = ["dim1": "value2", "dim2": "value2"]
+        let labels3 = ["dim1": "value1"]
 
         for _ in 0 ..< 10 {
             testCounter.add(value: 100, labelset: meter.getLabelSet(labels: labels1))
@@ -81,6 +84,10 @@ class PrometheusExporterTests: XCTestCase {
             testMeasure.record(value: 100, labelset: meter.getLabelSet(labels: labels1))
             testMeasure.record(value: 5, labelset: meter.getLabelSet(labels: labels1))
             testMeasure.record(value: 500, labelset: meter.getLabelSet(labels: labels1))
+
+            testHistogram.record(value: 8, labelset: meter.getLabelSet(labels: labels3))
+            testHistogram.record(value: 20, labelset: meter.getLabelSet(labels: labels3))
+            testHistogram.record(value: 30, labelset: meter.getLabelSet(labels: labels3))
         }
         return meterProvider
     }
@@ -101,5 +108,17 @@ class PrometheusExporterTests: XCTestCase {
         XCTAssert(responseText.contains("testMeasure{dim1=\"value1\",quantile=\"0\"} 5") || responseText.contains("testMeasure{quantile=\"0\",dim1=\"value1\"} 5"))
         // Max is 500
         XCTAssert(responseText.contains("testMeasure{dim1=\"value1\",quantile=\"1\"} 500") || responseText.contains("testMeasure{quantile=\"1\",dim1=\"value1\"} 500"))
+
+        // Validate histogram.
+        XCTAssert(responseText.contains("# TYPE testHistogram histogram"))
+        // sum is 58 = 8 + 20 + 30
+        XCTAssert(responseText.contains("testHistogram_sum{dim1=\"value1\"} 58"))
+        // count is 1 * 3
+        XCTAssert(responseText.contains("testHistogram_count{dim1=\"value1\"} 3"))
+        // validate le
+        XCTAssert(responseText.contains("testHistogram{dim1=\"value1\",le=\"5.000000\"} 0") || responseText.contains("testHistogram{le=\"5.000000\",dim1=\"value1\"} 0"))
+        XCTAssert(responseText.contains("testHistogram{dim1=\"value1\",le=\"10.000000\"} 1") || responseText.contains("testHistogram{le=\"10.000000\",dim1=\"value1\"} 1"))
+        XCTAssert(responseText.contains("testHistogram{dim1=\"value1\",le=\"25.000000\"} 1") || responseText.contains("testHistogram{le=\"25.000000\",dim1=\"value1\"} 1"))
+        XCTAssert(responseText.contains("testHistogram{dim1=\"value1\",le=\"+Inf\"} 1") || responseText.contains("testHistogram{le=\"+Inf\",dim1=\"value1\"} 1"))
     }
 }