Added wildcard support for meter sources.

src/OpenTelemetry/Metrics/MeterProviderSdk.cs

@@ -19,6 +19,7 @@
 using System.Diagnostics;
 using System.Diagnostics.Metrics;
 using System.Linq;
+using System.Text.RegularExpressions;
 using OpenTelemetry.Internal;
 using OpenTelemetry.Resources;
 
@@ -87,10 +88,38 @@ internal MeterProviderSdk(
             }
 
             // Setup Listener
-            var meterSourcesToSubscribe = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);
-            foreach (var name in meterSources)
+            var meterSourcesToSubscribe = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+            if (meterSources.Any())
             {
-                meterSourcesToSubscribe[name] = true;
+                var wildcardMode = false;
+                foreach (var meterSource in meterSources)
+                {
+                    if (meterSource.Contains('*'))
+                    {
+                        wildcardMode = true;
+                        break;
+                    }
+                }
+
+                if (wildcardMode)
+                {
+                    Regex regex = GetWildcardRegex(meterSources);
+                    foreach (var meterSource in meterSources)
+                    {
+                        if (regex.IsMatch(meterSource))
+                        {
+                            meterSourcesToSubscribe.Add(meterSource);
+                        }
+                    }
+                }
+                else
+                {
+                    foreach (var meterSource in meterSources)
+                    {
+                        meterSourcesToSubscribe.Add(meterSource);
+                    }
+                }
             }
 
             this.listener = new MeterListener();
@@ -99,7 +128,7 @@ internal MeterProviderSdk(
             {
                 this.listener.InstrumentPublished = (instrument, listener) =>
                 {
-                    if (meterSourcesToSubscribe.ContainsKey(instrument.Meter.Name))
+                    if (meterSourcesToSubscribe.Contains(instrument.Meter.Name))
                     {
                         // Creating list with initial capacity as the maximum
                         // possible size, to avoid any array resize/copy internally.
@@ -197,7 +226,7 @@ internal MeterProviderSdk(
             {
                 this.listener.InstrumentPublished = (instrument, listener) =>
                 {
-                    if (meterSourcesToSubscribe.ContainsKey(instrument.Meter.Name))
+                    if (meterSourcesToSubscribe.Contains(instrument.Meter.Name))
                     {
                         var metricName = instrument.Name;
                         Metric metric = null;
@@ -243,6 +272,12 @@ internal MeterProviderSdk(
 
             this.listener.MeasurementsCompleted = (instrument, state) => this.MeasurementsCompleted(instrument, state);
             this.listener.Start();
+
+            static Regex GetWildcardRegex(IEnumerable<string> collection)
+            {
+                var pattern = '^' + string.Join("|", from name in collection select "(?:" + Regex.Escape(name).Replace("\\*", ".*") + ')') + '$';
+                return new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
+            }
         }
 
         internal Resource Resource { get; }

test/OpenTelemetry.Tests/Metrics/MetricAPITest.cs

@@ -165,6 +165,36 @@ void ProcessExport(Batch<Metric> batch)
             Assert.Equal(1, metricCount);
         }
 
+        [Fact]
+        public void WildCardTest()
+        {
+            var metricItems = new List<Metric>();
+            int metricCount = 0;
+            var metricExporter = new TestExporter<Metric>(ProcessExport);
+
+            void ProcessExport(Batch<Metric> batch)
+            {
+                foreach (var metric in batch)
+                {
+                    metricCount++;
+                }
+            }
+
+            var meterSources = new[] { "*", "MeterSource.*", "MeterSource.*.Namespace" };
+
+            using var meter1 = new Meter(meterSources[0]);
+            using var meter2 = new Meter(meterSources[1]);
+            using var meter3 = new Meter(meterSources[2]);
+
+            using var meterProvider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meterSources[0])
+                .AddMeter(meterSources[1])
+                .AddMeter(meterSources[2])
+                .Build();
+
+            // Do some tests
+        }
+
         [Theory]
         [InlineData(true)]
         [InlineData(false)]