Review feedback: filter already registered post-processors

Author: bart-vmware

src/Configuration/src/CloudFoundry/ServiceBindings/CloudFoundryServiceBindingConfigurationSource.cs

@@ -11,14 +11,15 @@ namespace Steeltoe.Configuration.CloudFoundry.ServiceBindings;
 internal sealed class CloudFoundryServiceBindingConfigurationSource : PostProcessorConfigurationSource, IConfigurationSource
 {
     private readonly IServiceBindingsReader _serviceBindingsReader;
-    private readonly CloudFoundryServiceBrokerTypes _brokerTypes;
+
+    public CloudFoundryServiceBrokerTypes BrokerTypes { get; }
 
     public CloudFoundryServiceBindingConfigurationSource(IServiceBindingsReader serviceBindingsReader, CloudFoundryServiceBrokerTypes brokerTypes)
     {
         ArgumentNullException.ThrowIfNull(serviceBindingsReader);
 
         _serviceBindingsReader = serviceBindingsReader;
-        _brokerTypes = brokerTypes;
+        BrokerTypes = brokerTypes;
     }
 
     public IConfigurationProvider Build(IConfigurationBuilder builder)
@@ -31,6 +32,6 @@ public IConfigurationProvider Build(IConfigurationBuilder builder)
 
     private string DebuggerToString()
     {
-        return $"{GetType().FullName} ({_brokerTypes})";
+        return $"{GetType().FullName} ({BrokerTypes})";
     }
 }

src/Configuration/src/CloudFoundry/ServiceBindings/ConfigurationBuilderExtensions.cs

@@ -119,9 +119,11 @@ public static IConfigurationBuilder AddCloudFoundryServiceBindings(this IConfigu
         ArgumentNullException.ThrowIfNull(ignoreKeyPredicate);
         ArgumentNullException.ThrowIfNull(loggerFactory);
 
-        if (brokerTypes != CloudFoundryServiceBrokerTypes.None)
+        CloudFoundryServiceBrokerTypes missingBrokerTypes = GetMissingBrokerTypes(builder, brokerTypes);
+
+        if (missingBrokerTypes != CloudFoundryServiceBrokerTypes.None)
         {
-            var source = new CloudFoundryServiceBindingConfigurationSource(serviceBindingsReader ?? DefaultReader, brokerTypes)
+            var source = new CloudFoundryServiceBindingConfigurationSource(serviceBindingsReader ?? DefaultReader, missingBrokerTypes)
             {
                 IgnoreKeyPredicate = ignoreKeyPredicate
             };
@@ -130,13 +132,28 @@ public static IConfigurationBuilder AddCloudFoundryServiceBindings(this IConfigu
             // WebApplicationBuilder immediately builds the configuration provider and loads it, which executes the post-processors.
             // Therefore, adding post-processors afterward is a no-op.
 
-            RegisterPostProcessors(source, brokerTypes, loggerFactory);
+            RegisterPostProcessors(source, missingBrokerTypes, loggerFactory);
             builder.Add(source);
         }
 
         return builder;
     }
 
+    private static CloudFoundryServiceBrokerTypes GetMissingBrokerTypes(IConfigurationBuilder builder, CloudFoundryServiceBrokerTypes brokerTypesRequested)
+    {
+        CloudFoundryServiceBrokerTypes missingBrokerTypes = brokerTypesRequested;
+
+        if (brokerTypesRequested != CloudFoundryServiceBrokerTypes.None)
+        {
+            foreach (var existingSource in builder.EnumerateSources<CloudFoundryServiceBindingConfigurationSource>())
+            {
+                missingBrokerTypes &= ~existingSource.BrokerTypes;
+            }
+        }
+
+        return missingBrokerTypes;
+    }
+
     private static void RegisterPostProcessors(CloudFoundryServiceBindingConfigurationSource source, CloudFoundryServiceBrokerTypes brokerTypes,
         ILoggerFactory loggerFactory)
     {

src/Configuration/test/CloudFoundry.Test/ServiceBindings/ConfigurationBuilderExtensionsTest.cs

@@ -68,6 +68,24 @@ public void AddCloudFoundryServiceBindings_RegistersSubsetOfProcessors()
         source.PostProcessors.Should().HaveCount(2);
     }
 
+    [Fact]
+    public void AddCloudFoundryServiceBindings_DoesNotAddMultipleSourcesForSamePostProcessor()
+    {
+        var builder = new ConfigurationBuilder();
+
+        builder.AddCloudFoundryServiceBindings(CloudFoundryServiceBrokerTypes.None);
+        builder.AddCloudFoundryServiceBindings(CloudFoundryServiceBrokerTypes.PostgreSql | CloudFoundryServiceBrokerTypes.MySql);
+        builder.AddCloudFoundryServiceBindings(CloudFoundryServiceBrokerTypes.PostgreSql | CloudFoundryServiceBrokerTypes.SqlServer);
+        builder.AddCloudFoundryServiceBindings(CloudFoundryServiceBrokerTypes.MySql | CloudFoundryServiceBrokerTypes.RabbitMQ);
+        builder.AddCloudFoundryServiceBindings(CloudFoundryServiceBrokerTypes.SqlServer | CloudFoundryServiceBrokerTypes.RabbitMQ);
+
+        var sources = builder.Sources.OfType<CloudFoundryServiceBindingConfigurationSource>().Should().HaveCount(3).And.Subject.ToArray();
+
+        sources[0].BrokerTypes.Should().Be(CloudFoundryServiceBrokerTypes.PostgreSql | CloudFoundryServiceBrokerTypes.MySql);
+        sources[1].BrokerTypes.Should().Be(CloudFoundryServiceBrokerTypes.SqlServer);
+        sources[2].BrokerTypes.Should().Be(CloudFoundryServiceBrokerTypes.RabbitMQ);
+    }
+
     [Fact]
     public void AddCloudFoundryServiceBindings_EnvironmentVariableSet_LoadsServiceBindings()
     {