[Exporter.Prometheus] Nullable (#5791)

Co-authored-by: Mikel Blanchard <[email protected]>

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

@@ -0,0 +1 @@
+#nullable enable

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

@@ -4,18 +4,18 @@ 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.get -> string?
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.ScrapeEndpointPath.set -> void
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.ScrapeResponseCacheDurationMilliseconds.get -> int
 OpenTelemetry.Exporter.PrometheusAspNetCoreOptions.ScrapeResponseCacheDurationMilliseconds.set -> void
 OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions
-static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder app) -> Microsoft.AspNetCore.Builder.IApplicationBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder app, OpenTelemetry.Metrics.MeterProvider meterProvider, System.Func<Microsoft.AspNetCore.Http.HttpContext, bool> predicate, string path, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder> configureBranchedPipeline, string optionsName) -> Microsoft.AspNetCore.Builder.IApplicationBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder app, string path) -> Microsoft.AspNetCore.Builder.IApplicationBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder app, System.Func<Microsoft.AspNetCore.Http.HttpContext, bool> predicate) -> Microsoft.AspNetCore.Builder.IApplicationBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder endpoints) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder endpoints, string path) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder
-static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder endpoints, string path, OpenTelemetry.Metrics.MeterProvider meterProvider, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder> configureBranchedPipeline, string optionsName) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder
-static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, string name, System.Action<OpenTelemetry.Exporter.PrometheusAspNetCoreOptions> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Action<OpenTelemetry.Exporter.PrometheusAspNetCoreOptions> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder! app) -> Microsoft.AspNetCore.Builder.IApplicationBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder! app, OpenTelemetry.Metrics.MeterProvider? meterProvider, System.Func<Microsoft.AspNetCore.Http.HttpContext!, bool>? predicate, string? path, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder!>? configureBranchedPipeline, string? optionsName) -> Microsoft.AspNetCore.Builder.IApplicationBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder! app, string! path) -> Microsoft.AspNetCore.Builder.IApplicationBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterApplicationBuilderExtensions.UseOpenTelemetryPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Builder.IApplicationBuilder! app, System.Func<Microsoft.AspNetCore.Http.HttpContext!, bool>! predicate) -> Microsoft.AspNetCore.Builder.IApplicationBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder! endpoints) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder! endpoints, string! path) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder!
+static Microsoft.AspNetCore.Builder.PrometheusExporterEndpointRouteBuilderExtensions.MapPrometheusScrapingEndpoint(this Microsoft.AspNetCore.Routing.IEndpointRouteBuilder! endpoints, string? path, OpenTelemetry.Metrics.MeterProvider? meterProvider, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder!>? configureBranchedPipeline, string? optionsName) -> Microsoft.AspNetCore.Builder.IEndpointConventionBuilder!
+static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!
+static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder! builder, string? name, System.Action<OpenTelemetry.Exporter.PrometheusAspNetCoreOptions!>? configure) -> OpenTelemetry.Metrics.MeterProviderBuilder!
+static OpenTelemetry.Metrics.PrometheusExporterMeterProviderBuilderExtensions.AddPrometheusExporter(this OpenTelemetry.Metrics.MeterProviderBuilder! builder, System.Action<OpenTelemetry.Exporter.PrometheusAspNetCoreOptions!>! configure) -> OpenTelemetry.Metrics.MeterProviderBuilder!

src/OpenTelemetry.Exporter.Prometheus.AspNetCore/OpenTelemetry.Exporter.Prometheus.AspNetCore.csproj

@@ -7,9 +7,6 @@
     <PackageTags>$(PackageTags);prometheus;metrics</PackageTags>
     <MinVerTagPrefix>coreunstable-</MinVerTagPrefix>
     <DefineConstants>$(DefineConstants);PROMETHEUS_ASPNETCORE</DefineConstants>
-
-    <!-- this is temporary. will remove in future PR. -->
-    <Nullable>disable</Nullable>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(RunningDotNetPack)' != 'true'">
@@ -25,7 +22,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <Compile Include="$(RepoRoot)\src\Shared\Guard.cs" Link="Includes\Guard.cs" />
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus.HttpListener\Internal\PrometheusCollectionManager.cs" Link="Includes/PrometheusCollectionManager.cs" />
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus.HttpListener\Internal\PrometheusExporter.cs" Link="Includes/PrometheusExporter.cs" />
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus.HttpListener\Internal\PrometheusExporterEventSource.cs" Link="Includes/PrometheusExporterEventSource.cs" />
@@ -36,6 +32,8 @@
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus.HttpListener\Internal\PrometheusMetric.cs" Link="Includes/PrometheusMetric.cs" />
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus.HttpListener\Internal\PrometheusHeadersParser.cs" Link="Includes/PrometheusHeadersParser.cs" />
     <Compile Include="$(RepoRoot)\src\Shared\ExceptionExtensions.cs" Link="Includes\ExceptionExtensions.cs" />
+    <Compile Include="$(RepoRoot)\src\Shared\Guard.cs" Link="Includes\Guard.cs" />
+    <Compile Include="$(RepoRoot)\src\Shared\Shims\NullableAttributes.cs" Link="Includes\Shims\NullableAttributes.cs" />
   </ItemGroup>
 
 </Project>

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

@@ -15,7 +15,7 @@ public class PrometheusAspNetCoreOptions
     /// <summary>
     /// Gets or sets the path to use for the scraping endpoint. Default value: "/metrics".
     /// </summary>
-    public string ScrapeEndpointPath { get; set; } = DefaultScrapeEndpointPath;
+    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"/>.

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

@@ -93,11 +93,11 @@ public static IApplicationBuilder UseOpenTelemetryPrometheusScrapingEndpoint(thi
     /// cref="IApplicationBuilder"/> for chaining calls.</returns>
     public static IApplicationBuilder UseOpenTelemetryPrometheusScrapingEndpoint(
         this IApplicationBuilder app,
-        MeterProvider meterProvider,
-        Func<HttpContext, bool> predicate,
-        string path,
-        Action<IApplicationBuilder> configureBranchedPipeline,
-        string optionsName)
+        MeterProvider? meterProvider,
+        Func<HttpContext, bool>? predicate,
+        string? path,
+        Action<IApplicationBuilder>? configureBranchedPipeline,
+        string? optionsName)
     {
         // Note: Order is important here. MeterProvider is accessed before
         // GetOptions<PrometheusAspNetCoreOptions> so that any changes made to

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

@@ -64,10 +64,10 @@ public static IEndpointConventionBuilder MapPrometheusScrapingEndpoint(this IEnd
     /// <returns>A convention routes for the Prometheus scraping endpoint.</returns>
     public static IEndpointConventionBuilder MapPrometheusScrapingEndpoint(
         this IEndpointRouteBuilder endpoints,
-        string path,
-        MeterProvider meterProvider,
-        Action<IApplicationBuilder> configureBranchedPipeline,
-        string optionsName)
+        string? path,
+        MeterProvider? meterProvider,
+        Action<IApplicationBuilder>? configureBranchedPipeline,
+        string? optionsName)
     {
         var builder = endpoints.CreateApplicationBuilder();
 

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

@@ -37,13 +37,13 @@ public static MeterProviderBuilder AddPrometheusExporter(
     /// Adds <see cref="PrometheusExporter"/> to the <see cref="MeterProviderBuilder"/>.
     /// </summary>
     /// <param name="builder"><see cref="MeterProviderBuilder"/> builder to use.</param>
-    /// <param name="name">Name which is used when retrieving options.</param>
-    /// <param name="configure">Callback action for configuring <see cref="PrometheusAspNetCoreOptions"/>.</param>
+    /// <param name="name">Optional name which is used when retrieving options.</param>
+    /// <param name="configure">Optional callback action for configuring <see cref="PrometheusAspNetCoreOptions"/>.</param>
     /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
     public static MeterProviderBuilder AddPrometheusExporter(
         this MeterProviderBuilder builder,
-        string name,
-        Action<PrometheusAspNetCoreOptions> configure)
+        string? name,
+        Action<PrometheusAspNetCoreOptions>? configure)
     {
         Guard.ThrowIfNull(builder);
 

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

@@ -25,8 +25,9 @@ internal sealed class PrometheusExporterMiddleware
     public PrometheusExporterMiddleware(MeterProvider meterProvider, RequestDelegate next)
     {
         Guard.ThrowIfNull(meterProvider);
+        Guard.ThrowIfNull(next);
 
-        if (!meterProvider.TryFindExporter(out PrometheusExporter exporter))
+        if (!meterProvider.TryFindExporter(out PrometheusExporter? exporter))
         {
             throw new ArgumentException("A PrometheusExporter could not be found configured on the provided MeterProvider.");
         }
@@ -36,6 +37,8 @@ public PrometheusExporterMiddleware(MeterProvider meterProvider, RequestDelegate
 
     internal PrometheusExporterMiddleware(PrometheusExporter exporter)
     {
+        Debug.Assert(exporter != null, "exporter was null");
+
         this.exporter = exporter;
     }
 
@@ -71,7 +74,7 @@ public async Task InvokeAsync(HttpContext httpContext)
                         ? "application/openmetrics-text; version=1.0.0; charset=utf-8"
                         : "text/plain; charset=utf-8; version=0.0.4";
 
-                    await response.Body.WriteAsync(dataView.Array, 0, dataView.Count).ConfigureAwait(false);
+                    await response.Body.WriteAsync(dataView.Array!, 0, dataView.Count).ConfigureAwait(false);
                 }
                 else
                 {
@@ -93,8 +96,6 @@ public async Task InvokeAsync(HttpContext httpContext)
                 response.StatusCode = 500;
             }
         }
-
-        this.exporter.OnExport = null;
     }
 
     private static bool AcceptsOpenMetrics(HttpRequest request)

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

@@ -0,0 +1 @@
+#nullable enable

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

@@ -1,12 +1,12 @@
 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.get -> System.Collections.Generic.IReadOnlyCollection<string!>!
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.UriPrefixes.set -> void
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.PrometheusHttpListenerOptions() -> void
-OpenTelemetry.Exporter.PrometheusHttpListenerOptions.ScrapeEndpointPath.get -> string
+OpenTelemetry.Exporter.PrometheusHttpListenerOptions.ScrapeEndpointPath.get -> string?
 OpenTelemetry.Exporter.PrometheusHttpListenerOptions.ScrapeEndpointPath.set -> void
 OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions
-static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder builder) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder builder, string name, System.Action<OpenTelemetry.Exporter.PrometheusHttpListenerOptions> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Action<OpenTelemetry.Exporter.PrometheusHttpListenerOptions> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!
+static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder! builder, string? name, System.Action<OpenTelemetry.Exporter.PrometheusHttpListenerOptions!>? configure) -> OpenTelemetry.Metrics.MeterProviderBuilder!
+static OpenTelemetry.Metrics.PrometheusHttpListenerMeterProviderBuilderExtensions.AddPrometheusHttpListener(this OpenTelemetry.Metrics.MeterProviderBuilder! builder, System.Action<OpenTelemetry.Exporter.PrometheusHttpListenerOptions!>! configure) -> OpenTelemetry.Metrics.MeterProviderBuilder!

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

@@ -1,6 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using OpenTelemetry.Metrics;
 
@@ -12,7 +13,7 @@ internal sealed class PrometheusCollectionManager
 
     private readonly PrometheusExporter exporter;
     private readonly int scrapeResponseCacheDurationMilliseconds;
-    private readonly Func<Batch<Metric>, ExportResult> onCollectRef;
+    private readonly PrometheusExporter.ExportFunc onCollectRef;
     private readonly Dictionary<Metric, PrometheusMetric> metricsCache;
     private readonly HashSet<string> scopes;
     private int metricsCacheCount;
@@ -26,7 +27,7 @@ internal sealed class PrometheusCollectionManager
     private DateTime? previousOpenMetricsDataViewGeneratedAtUtc;
     private int readerCount;
     private bool collectionRunning;
-    private TaskCompletionSource<CollectionResponse> collectionTcs;
+    private TaskCompletionSource<CollectionResponse>? collectionTcs;
 
     public PrometheusCollectionManager(PrometheusExporter exporter)
     {
@@ -115,7 +116,7 @@ public Task<CollectionResponse> EnterCollect(bool openMetricsRequested)
                 ? this.previousOpenMetricsDataViewGeneratedAtUtc
                 : this.previousPlainTextDataViewGeneratedAtUtc;
 
-            response = new CollectionResponse(this.previousOpenMetricsDataView, this.previousPlainTextDataView, previousDataViewGeneratedAtUtc.Value, fromCache: false);
+            response = new CollectionResponse(this.previousOpenMetricsDataView, this.previousPlainTextDataView, previousDataViewGeneratedAtUtc!.Value, fromCache: false);
         }
         else
         {
@@ -188,14 +189,16 @@ private void WaitForReadersToComplete()
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private bool ExecuteCollect(bool openMetricsRequested)
     {
+        Debug.Assert(this.exporter.Collect != null, "this.exporter.Collect was null");
+
         this.exporter.OnExport = this.onCollectRef;
         this.exporter.OpenMetricsRequested = openMetricsRequested;
-        var result = this.exporter.Collect(Timeout.Infinite);
+        var result = this.exporter.Collect!(Timeout.Infinite);
         this.exporter.OnExport = null;
         return result;
     }
 
-    private ExportResult OnCollect(Batch<Metric> metrics)
+    private ExportResult OnCollect(in Batch<Metric> metrics)
     {
         var cursor = 0;
         ref byte[] buffer = ref (this.exporter.OpenMetricsRequested ? ref this.openMetricsBuffer : ref this.plainTextBuffer);