Option to not add _total suffix to counter metrics in Prometheus exporter

src/OpenTelemetry.Exporter.Prometheus.AspNetCore/.publicApi/PublicAPI.Unshipped.txt

@@ -1,6 +1,8 @@
 Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions
 Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions
+OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.DisableTotalNameSuffixForCounters.get -> bool
+OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.DisableTotalNameSuffixForCounters.set -> void
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.PrometheusAspNetCoreOptions() -> void
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.ScrapeEndpointPath.get -> string
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.ScrapeEndpointPath.set -> void

src/OpenTelemetry.Exporter.Prometheus.AspNetCore/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Added option to disable _total suffix addition to counter metrics in
+  Prometheus exporter
+  ([#5305](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5305))
+
 * Export OpenMetrics format from Prometheus exporters ([#5107](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5107))
 * For requests with OpenMetrics format, scope info is automatically added
   ([#5086](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5086)

src/OpenTelemetry.Exporter.Prometheus.AspNetCore/PrometheusAspNetCoreOptions.cs

@@ -17,6 +17,15 @@ public class PrometheusAspNetCoreOptions
     /// </summary>
     public string ScrapeEndpointPath { get; set; } = DefaultScrapeEndpointPath;
 
+    /// <summary>
+    /// Gets or sets a value indicating whether addition of _total suffix for counter metric names is disabled. Default value: <see langword="false"/>.
+    /// </summary>
+    public bool DisableTotalNameSuffixForCounters
+    {
+        get => this.ExporterOptions.DisableTotalNameSuffixForCounters;
+        set => this.ExporterOptions.DisableTotalNameSuffixForCounters = value;
+    }
+
     /// <summary>
     /// Gets or sets the cache duration in milliseconds for scrape responses. Default value: 300.
     /// </summary>

src/OpenTelemetry.Exporter.Prometheus.HttpListener/.publicApi/PublicAPI.Unshipped.txt

@@ -1,4 +1,6 @@
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions
+OpenTelemetry.Exporter.PrometheusHttpListenerOptions.DisableTotalNameSuffixForCounters.get -> bool
+OpenTelemetry.Exporter.PrometheusHttpListenerOptions.DisableTotalNameSuffixForCounters.set -> void
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.UriPrefixes.get -> System.Collections.Generic.IReadOnlyCollection<string>
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.UriPrefixes.set -> void
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.PrometheusHttpListenerOptions() -> void

src/OpenTelemetry.Exporter.Prometheus.HttpListener/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Added option to disable _total suffix addition to counter metrics in
+  Prometheus exporter
+  ([#5305](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5305))
+
 * Export OpenMetrics format from Prometheus exporters
   ([#5107](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5107))
 

src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusCollectionManager.cs

@@ -283,7 +283,7 @@ private PrometheusMetric GetPrometheusMetric(Metric metric)
         // Optimize writing metrics with bounded cache that has pre-calculated Prometheus names.
         if (!this.metricsCache.TryGetValue(metric, out var prometheusMetric))
         {
-            prometheusMetric = PrometheusMetric.Create(metric);
+            prometheusMetric = PrometheusMetric.Create(metric, this.exporter.DisableTotalNameSuffixForCounters);
 
             // Add to the cache if there is space.
             if (this.metricsCacheCount < MaxCachedMetrics)

src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusExporter.cs

@@ -25,6 +25,7 @@ public PrometheusExporter(PrometheusExporterOptions options)
         Guard.ThrowIfNull(options);
 
         this.ScrapeResponseCacheDurationMilliseconds = options.ScrapeResponseCacheDurationMilliseconds;
+        this.DisableTotalNameSuffixForCounters = options.DisableTotalNameSuffixForCounters;
 
         this.CollectionManager = new PrometheusCollectionManager(this);
     }
@@ -50,6 +51,8 @@ internal Func<Batch<Metric>, ExportResult> OnExport
 
     internal int ScrapeResponseCacheDurationMilliseconds { get; }
 
+    internal bool DisableTotalNameSuffixForCounters { get; }
+
     internal bool OpenMetricsRequested { get; set; }
 
     /// <inheritdoc/>

src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusExporterOptions.cs

@@ -28,4 +28,9 @@ public int ScrapeResponseCacheDurationMilliseconds
             this.scrapeResponseCacheDurationMilliseconds = value;
         }
     }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether addition of _total suffix for counter metric names is disabled. Default value: <see langword="false"/>.
+    /// </summary>
+    public bool DisableTotalNameSuffixForCounters { get; set; }
 }

src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusMetric.cs

@@ -19,7 +19,7 @@ UpDownCounter becomes gauge
         PrometheusType.Untyped, PrometheusType.Counter, PrometheusType.Gauge, PrometheusType.Summary, PrometheusType.Histogram, PrometheusType.Histogram, PrometheusType.Histogram, PrometheusType.Histogram, PrometheusType.Gauge,
     };
 
-    public PrometheusMetric(string name, string unit, PrometheusType type)
+    public PrometheusMetric(string name, string unit, PrometheusType type, bool disableTotalNameSuffixForCounters)
     {
         // The metric name is
         // required to match the regex: `[a-zA-Z_:]([a-zA-Z0-9_:])*`. Invalid characters
@@ -48,7 +48,7 @@ public PrometheusMetric(string name, string unit, PrometheusType type)
         // If the metric name for monotonic Sum metric points does not end in a suffix of `_total` a suffix of `_total` MUST be added by default, otherwise the name MUST remain unchanged.
         // Exporters SHOULD provide a configuration option to disable the addition of `_total` suffixes.
         // https://github.com/open-telemetry/opentelemetry-specification/blob/b2f923fb1650dde1f061507908b834035506a796/specification/compatibility/prometheus_and_openmetrics.md#L286
-        if (type == PrometheusType.Counter && !sanitizedName.EndsWith("_total"))
+        if (type == PrometheusType.Counter && !sanitizedName.EndsWith("_total") && !disableTotalNameSuffixForCounters)
         {
             sanitizedName += "_total";
         }
@@ -71,9 +71,9 @@ public PrometheusMetric(string name, string unit, PrometheusType type)
 
     public PrometheusType Type { get; }
 
-    public static PrometheusMetric Create(Metric metric)
+    public static PrometheusMetric Create(Metric metric, bool disableTotalNameSuffixForCounters)
     {
-        return new PrometheusMetric(metric.Name, metric.Unit, GetPrometheusType(metric));
+        return new PrometheusMetric(metric.Name, metric.Unit, GetPrometheusType(metric), disableTotalNameSuffixForCounters);
     }
 
     internal static string SanitizeMetricName(string metricName)

src/OpenTelemetry.Exporter.Prometheus.HttpListener/PrometheusHttpListenerMeterProviderBuilderExtensions.cs

@@ -65,7 +65,11 @@ public static MeterProviderBuilder AddPrometheusHttpListener(
     private static MetricReader BuildPrometheusHttpListenerMetricReader(
         PrometheusHttpListenerOptions options)
     {
-        var exporter = new PrometheusExporter(new PrometheusExporterOptions { ScrapeResponseCacheDurationMilliseconds = 0 });
+        var exporter = new PrometheusExporter(new PrometheusExporterOptions
+        {
+            ScrapeResponseCacheDurationMilliseconds = 0,
+            DisableTotalNameSuffixForCounters = options.DisableTotalNameSuffixForCounters,
+        });
 
         var reader = new BaseExportingMetricReader(exporter)
         {

src/OpenTelemetry.Exporter.Prometheus.HttpListener/PrometheusHttpListenerOptions.cs

@@ -17,6 +17,11 @@ public class PrometheusHttpListenerOptions
     /// </summary>
     public string ScrapeEndpointPath { get; set; } = "/metrics";
 
+    /// <summary>
+    /// Gets or sets a value indicating whether addition of _total suffix for counter metric names is disabled. Default value: <see langword="false"/>.
+    /// </summary>
+    public bool DisableTotalNameSuffixForCounters { get; set; }
+
     /// <summary>
     /// Gets or sets the URI (Uniform Resource Identifier) prefixes to use for the http listener.
     /// Default value: <c>["http://localhost:9464/"]</c>.

test/Benchmarks/Exporter/PrometheusSerializerBenchmarks.cs

@@ -66,7 +66,7 @@ private PrometheusMetric GetPrometheusMetric(Metric metric)
     {
         if (!this.cache.TryGetValue(metric, out var prometheusMetric))
         {
-            prometheusMetric = PrometheusMetric.Create(metric);
+            prometheusMetric = PrometheusMetric.Create(metric, false);
             this.cache[metric] = prometheusMetric;
         }
 

test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusMetricTests.cs

@@ -118,84 +118,97 @@ public void Unit_AnnotationMismatch_Close()
     [Fact]
     public void Name_SpecialCaseGuage_AppendRatio()
     {
-        AssertName("sample", "1", PrometheusType.Gauge, "sample_ratio");
+        AssertName("sample", "1", PrometheusType.Gauge, false, "sample_ratio");
     }
 
     [Fact]
     public void Name_GuageWithUnit_NoAppendRatio()
     {
-        AssertName("sample", "unit", PrometheusType.Gauge, "sample_unit");
+        AssertName("sample", "unit", PrometheusType.Gauge, false, "sample_unit");
     }
 
     [Fact]
     public void Name_SpecialCaseCounter_AppendTotal()
     {
-        AssertName("sample", "unit", PrometheusType.Counter, "sample_unit_total");
+        AssertName("sample", "unit", PrometheusType.Counter, false, "sample_unit_total");
     }
 
     [Fact]
     public void Name_SpecialCaseCounterWithoutUnit_DropUnitAppendTotal()
     {
-        AssertName("sample", "1", PrometheusType.Counter, "sample_total");
+        AssertName("sample", "1", PrometheusType.Counter, false, "sample_total");
+    }
+
+    [Fact]
+    public void Name_DisableTotalSuffixAddition_TotalNotAppended()
+    {
+        AssertName("sample", "1", PrometheusType.Counter, true, "sample");
+    }
+
+    [Fact]
+    public void Name_TotalSuffixAlreadyPresent_DisableTotalSuffixAddition_TotalNotRemoved()
+    {
+        AssertName("sample_total", "1", PrometheusType.Counter, true, "sample_total");
     }
 
     [Fact]
     public void Name_SpecialCaseCounterWithNumber_AppendTotal()
     {
-        AssertName("sample", "2", PrometheusType.Counter, "sample_2_total");
+        AssertName("sample", "2", PrometheusType.Counter, false, "sample_2_total");
     }
 
     [Fact]
     public void Name_UnsupportedMetricNameChars_Drop()
     {
-        AssertName("s%%ple", "%/m", PrometheusType.Summary, "s_ple_percent_per_minute");
+        AssertName("s%%ple", "%/m", PrometheusType.Summary, false, "s_ple_percent_per_minute");
     }
 
     [Fact]
     public void Name_UnitOtherThanOne_Normal()
     {
-        AssertName("metric_name", "2", PrometheusType.Summary, "metric_name_2");
+        AssertName("metric_name", "2", PrometheusType.Summary, false, "metric_name_2");
     }
 
     [Fact]
     public void Name_UnitAlreadyPresentInName_NotAppended()
     {
-        AssertName("metric_name_total", "total", PrometheusType.Counter, "metric_name_total");
+        AssertName("metric_name_total", "total", PrometheusType.Counter, false, "metric_name_total");
     }
 
     [Fact]
     public void Name_UnitAlreadyPresentInName_TotalNonCounterType_NotAppended()
     {
-        AssertName("metric_name_total", "total", PrometheusType.Summary, "metric_name_total");
+        AssertName("metric_name_total", "total", PrometheusType.Summary, false, "metric_name_total");
     }
 
     [Fact]
     public void Name_UnitAlreadyPresentInName_CustomGauge_NotAppended()
     {
-        AssertName("metric_hertz", "hertz", PrometheusType.Gauge, "metric_hertz");
+        AssertName("metric_hertz", "hertz", PrometheusType.Gauge, false, "metric_hertz");
     }
 
     [Fact]
     public void Name_UnitAlreadyPresentInName_CustomCounter_NotAppended()
     {
-        AssertName("metric_hertz_total", "hertz_total", PrometheusType.Counter, "metric_hertz_total");
+        AssertName("metric_hertz_total", "hertz_total", PrometheusType.Counter, false, "metric_hertz_total");
     }
 
     [Fact]
     public void Name_UnitAlreadyPresentInName_OrderMatters_Appended()
     {
-        AssertName("metric_total_hertz", "hertz_total", PrometheusType.Counter, "metric_total_hertz_hertz_total");
+        AssertName("metric_total_hertz", "hertz_total", PrometheusType.Counter, false, "metric_total_hertz_hertz_total");
     }
 
     [Fact]
     public void Name_StartWithNumber_UnderscoreStart()
     {
-        AssertName("2_metric_name", "By", PrometheusType.Summary, "_metric_name_bytes");
+        AssertName("2_metric_name", "By", PrometheusType.Summary, false, "_metric_name_bytes");
     }
 
-    private static void AssertName(string name, string unit, PrometheusType type, string expected)
+    private static void AssertName(
+        string name, string unit, PrometheusType type, bool disableTotalNameSuffixForCounters, string expected)
     {
-        var prometheusMetric = new PrometheusMetric(name, unit, type);
+        var prometheusMetric = new PrometheusMetric(name, unit, type, disableTotalNameSuffixForCounters);
         Assert.Equal(expected, prometheusMetric.Name);
     }
 

test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusSerializerTests.cs

@@ -655,6 +655,6 @@ public void HistogramOneDimensionWithScopeVersion()
 
     private static int WriteMetric(byte[] buffer, int cursor, Metric metric, bool useOpenMetrics = false)
     {
-        return PrometheusSerializer.WriteMetric(buffer, cursor, metric, PrometheusMetric.Create(metric), useOpenMetrics);
+        return PrometheusSerializer.WriteMetric(buffer, cursor, metric, PrometheusMetric.Create(metric, false), useOpenMetrics);
     }
 }