Merge b38bb3b into 98c6ca7

Author: gabrielweyer

README.md

@@ -7,9 +7,9 @@ The Application Insights integration for Azure Functions `v3` and `v4` suffers f
 - Exceptions are logged twice for the HTTP binding
 - Exceptions are logged three times for the Service Bus binding
 
-The next issue has no impact on the cost of Application Insights but is related to the development experience. `TelemetryConfiguration` is not registered in the Inversion Of Control container when the Application Insights connection string is not set. Emitting a custom metric requires to inject the `TelemetryConfiguration`. Running locally without having configured the Application Insights connection string will then result in an exception.
+The next issue has no impact on the cost of Application Insights but is related to the development experience. `TelemetryConfiguration` is not registered in the Inversion Of Control container when the Application Insights connection string is not set. Emitting a custom metric requires injecting the `TelemetryConfiguration`. Running locally without having configured the Application Insights connection string will then result in an exception.
 
-The last issue is not related to Application Insights but also negatively affect developers' productivity. The custom Console logger provider used by the Azure Functions runtime does not include the stack trace when displaying an exception (for the HTTP binding at least).
+The last issue is not related to Application Insights but also negatively affects developers' productivity. The custom Console logger provider used by the Azure Functions runtime does not include the stack trace when displaying an exception (for the HTTP binding at least).
 
 If you are not familiar with some of the more advanced features of Application Insights, I suggest you go through the below references before reading the rest of this document:
 
@@ -41,8 +41,8 @@ dotnet add package AzureFunctions.Better.ApplicationInsights
 
 For the most basic integration, you need to provide:
 
-- `{ApplicationName}` used to set Application Insights' _Cloud role name_
-- `{TypeFromEntryAssembly}` typically would be `typeof(Startup)`. I read the [Assembly Informational Version][assembly-informational-version] of the entry assembly to set Application Insights' _Application version_ (I use _unknown_ as a fallback)
+- `{ApplicationName}` used to set Application Insights' _Cloud role name_ (optional). When not provided, the default behaviour is preserved (the _Cloud role name_ will be set to the Function App's name)
+- `{TypeFromEntryAssembly}` typically would be `typeof(Startup)`. When `{ApplicationName}` is provided, I read the [Assembly Informational Version][assembly-informational-version] of the entry assembly to set Application Insights' _Application version_ (I use _unknown_ as a fallback). When `{ApplicationName}` is not provided, _Application version_ will not be present on the telemetry items
 
 In your `Startup` `class` add the below snippet:
 
@@ -94,7 +94,7 @@ This is done by calling `AddCustomConsoleLogging`. You will then consistently ge
 
 ### Registering telemetry initializers
 
-:memo: The built-in integration supports telemetry initializers. The custom integration supports registering telemetry initializers in the same way than the built-in integration does.
+:memo: The built-in integration supports telemetry initializers. The custom integration supports registering telemetry initializers in the same way as the built-in integration does.
 
 Telemetry initializers can either be registered using `TImplementation`:
 
@@ -140,7 +140,7 @@ The customisation is configured using application settings:
 }
 ```
 
-If you don't want to use the `ApplicationInsights` key, you can provide another value when configuraing the customisation:
+If you don't want to use the `ApplicationInsights` key, you can provide another value when configuring the customisation:
 
 ```csharp
 var appInsightsOptions = new CustomApplicationInsightsOptionsBuilder(

src/AzureFunctionsTelemetry/ApplicationInsights/ApplicationInsightsServiceCollectionExtensions.cs

@@ -16,8 +16,8 @@ public static class ApplicationInsightsServiceCollectionExtensions
 {
     /// <summary>
     /// Extension method taking over the Application Insights' configuration so that we can register our own Telemetry
-    /// Initializers and Processors. Stamps each telemetry item with the application name and version. Discards as much
-    /// redundant telemetry as is humanely possible.
+    /// Initializers and Processors. Stamps each telemetry item with the application name and version (when provided).
+    /// Discards as much redundant telemetry as is humanely possible.
     /// </summary>
     /// <param name="services">The <see cref="IServiceCollection"/> holding all your precious types.</param>
     /// <param name="config">The <see cref="CustomApplicationInsightsConfig"/> configuring the Application Insights
@@ -45,10 +45,13 @@ public static IServiceCollection AddCustomApplicationInsights(
             throw new ArgumentNullException(nameof(services));
         }
 
-        var applicationVersion = GetAssemblyInformationalVersion(config.TypeFromEntryAssembly);
-        var applicationDescriptor = new ApplicationDescriptor(config.ApplicationName, applicationVersion);
-        services.AddSingleton(applicationDescriptor);
-        services.AddSingleton<ITelemetryInitializer, ApplicationInitializer>();
+        if (!string.IsNullOrWhiteSpace(config.ApplicationName))
+        {
+            var applicationVersion = GetAssemblyInformationalVersion(config.TypeFromEntryAssembly);
+            var applicationDescriptor = new ApplicationDescriptor(config.ApplicationName, applicationVersion);
+            services.AddSingleton(applicationDescriptor);
+            services.AddSingleton<ITelemetryInitializer, ApplicationInitializer>();
+        }
 
         services.AddOptions<CustomApplicationInsightsOptions>()
             .Configure<IConfiguration>((settings, configuration) =>

src/AzureFunctionsTelemetry/ApplicationInsights/CustomApplicationInsightsConfig.cs

@@ -9,7 +9,7 @@ public class CustomApplicationInsightsConfig
     /// <summary>
     /// Will be used as the 'Cloud role name'.
     /// </summary>
-    public string ApplicationName { get; }
+    public string? ApplicationName { get; }
     /// <summary>
     /// The 'AssemblyInformationalVersion' of the assembly will be used as the 'Application version'. Falls back to
     /// 'unknown'.
@@ -24,15 +24,18 @@ public class CustomApplicationInsightsConfig
     /// Even though you can call this constructor yourself, we provide
     /// <see cref="CustomApplicationInsightsConfigBuilder"/> to make it easier to configure the integration.
     /// </summary>
-    /// <param name="applicationName">Will be used as the 'Cloud role name'.</param>
+    /// <param name="applicationName">Will be used as the 'Cloud role name'. If not provided, we won't set the
+    /// 'Cloud role name' and we will not set the 'Application version'.</param>
     /// <param name="typeFromEntryAssembly">The 'AssemblyInformationalVersion' of the assembly will be used as the
-    /// 'Application version'. Falls back to 'unknown'.</param>
+    /// 'Application version'. Falls back to 'unknown'. If applicationName is not provided, we will not set the
+    /// 'Application version'. We also use this type to discover Service Bus triggered Functions so that we can apply
+    /// special handling to them.</param>
     /// <param name="configurationSectionName">The configuration section where we'll read the
     /// <see cref="CustomApplicationInsightsOptions"/> from.</param>
     /// <exception cref="ArgumentOutOfRangeException">The configuration section name should not be empty or consist only
     /// of white-space characters.</exception>
     public CustomApplicationInsightsConfig(
-        string applicationName,
+        string? applicationName,
         Type typeFromEntryAssembly,
         string configurationSectionName)
     {

src/AzureFunctionsTelemetry/ApplicationInsights/CustomApplicationInsightsConfigBuilder.cs

@@ -7,7 +7,7 @@ namespace Gabo.AzureFunctionsTelemetry.ApplicationInsights;
 /// </summary>
 public class CustomApplicationInsightsConfigBuilder
 {
-    private readonly string _applicationName;
+    private readonly string? _applicationName;
     private readonly Type _typeFromEntryAssembly;
     private string _configurationSectionName = "ApplicationInsights";
 
@@ -18,13 +18,26 @@ public class CustomApplicationInsightsConfigBuilder
     /// </summary>
     /// <param name="applicationName">Will be used as the 'Cloud role name'.</param>
     /// <param name="typeFromEntryAssembly">The 'AssemblyInformationalVersion' of the assembly will be used as the
-    /// 'Application version'. Falls back to 'unknown'.</param>
+    /// 'Application version'. Falls back to 'unknown'. We'll also use this type to discover Service Bus triggered
+    /// Functions so that we can apply special handling to them.</param>
     public CustomApplicationInsightsConfigBuilder(string applicationName, Type typeFromEntryAssembly)
     {
         _applicationName = applicationName;
         _typeFromEntryAssembly = typeFromEntryAssembly;
     }
 
+    /// <summary>
+    /// <para>Helps you configure Application Insights.</para>
+    /// <para>By default we'll read the <see cref="CustomApplicationInsightsOptions"/> from the 'ApplicationInsights'
+    /// configuration section.</para>
+    /// </summary>
+    /// <param name="typeFromEntryAssembly">We'll use this type to discover Service Bus triggered Functions so that we
+    /// can apply special handling to them.</param>
+    public CustomApplicationInsightsConfigBuilder(Type typeFromEntryAssembly)
+    {
+        _typeFromEntryAssembly = typeFromEntryAssembly;
+    }
+
     /// <summary>
     /// Allows you to set the configuration section where we'll read the <see cref="CustomApplicationInsightsOptions"/>
     /// from. The default value is 'ApplicationInsights'.

src/AzureFunctionsTelemetry/README.md

@@ -2,7 +2,7 @@
 
 Automatically discards redundant telemetry items such as Functions execution traces and duplicate exceptions. Allows you to register your own telemetry processor(s) that will be invoked on every telemetry item type.
 
-A more detailed documentation is available on [GitHub][documentation].
+More detailed documentation is available on [GitHub][documentation].
 
 ## Usage
 
@@ -20,10 +20,10 @@ builder.Services
 
 Where
 
-- `{ApplicationName}` is used to set Application Insights' _Cloud role name_
-- `{TypeFromEntryAssembly}` typically would be `typeof(Startup)`. I read the [Assembly Informational Version][assembly-informational-version] of the entry assembly to set Application Insights' _Application version_ (I use _unknown_ as a fallback)
+- `{ApplicationName}` used to set Application Insights' _Cloud role name_ (optional). When not provided, the default behaviour is preserved (the _Cloud role name_ will be set to the Function App's name)
+- `{TypeFromEntryAssembly}` typically would be `typeof(Startup)`. When `{ApplicationName}` is provided, I read the [Assembly Informational Version][assembly-informational-version] of the entry assembly to set Application Insights' _Application version_ (I use _unknown_ as a fallback). When `{ApplicationName}` is not provided, _Application version_ will not be present on the telemetry items
 
-Additionaly you can discard health requests and Service Bus trigger traces using application settings:
+Additionally you can discard health requests and Service Bus trigger traces using application settings:
 
 ```json
 {
@@ -36,7 +36,7 @@ Additionaly you can discard health requests and Service Bus trigger traces using
 }
 ```
 
-You can also add telemetry initializers and telelemetry processors:
+You can also add telemetry initializers and telemetry processors:
 
 ```csharp
 public override void Configure(IFunctionsHostBuilder builder)

tests/AzureFunctionsTelemetryTests/ApplicationInsights/ApplicationInsightsServiceCollectionExtensionsTests.cs

@@ -0,0 +1,45 @@
+using Microsoft.ApplicationInsights.Extensibility;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Gabo.AzureFunctionsTelemetryTests.ApplicationInsights;
+
+public class ApplicationInsightsServiceCollectionExtensionsTests
+{
+    [Fact]
+    public void GivenApplicationNameNotProvided_ThenDontRegisterApplicationInitializer()
+    {
+        // Arrange
+        var serviceCollection = new ServiceCollection();
+        var config = new CustomApplicationInsightsConfig(applicationName: null, typeof(StringHelper), "Q");
+
+        // Act
+        var updatedServiceCollection = serviceCollection.AddCustomApplicationInsights(config);
+
+        // Assert
+        var registeredTelemetryInitializers = GetTelemetryInitializers(updatedServiceCollection);
+        registeredTelemetryInitializers.Should().NotContain(typeof(ApplicationInitializer));
+    }
+
+    [Fact]
+    public void GivenApplicationNameProvided_ThenRegisterApplicationInitializer()
+    {
+        // Arrange
+        var serviceCollection = new ServiceCollection();
+        var config = new CustomApplicationInsightsConfig("app-name", typeof(StringHelper), "Q");
+
+        // Act
+        var updatedServiceCollection = serviceCollection.AddCustomApplicationInsights(config);
+
+        // Assert
+        var registeredTelemetryInitializers = GetTelemetryInitializers(updatedServiceCollection);
+        registeredTelemetryInitializers.Should().Contain(typeof(ApplicationInitializer));
+    }
+
+    private static IReadOnlyList<Type> GetTelemetryInitializers(IServiceCollection serviceCollection)
+    {
+        return serviceCollection
+            .Where(s => s.ServiceType == typeof(ITelemetryInitializer) && s.ImplementationType != null)
+            .Select(s => s.ImplementationType)
+            .ToList()!;
+    }
+}

tests/AzureFunctionsTelemetryTests/ApplicationInsights/CustomApplicationInsightsConfigBuilderTests.cs

@@ -0,0 +1,49 @@
+namespace Gabo.AzureFunctionsTelemetryTests.ApplicationInsights;
+
+public class CustomApplicationInsightsConfigBuilderTests
+{
+    private const string DefaultConfigurationSectionName = "ApplicationInsights";
+
+    [Fact]
+    public void GivenApplicationNameProvided_ThenSetConfig()
+    {
+        // Arrange
+        var builder = new CustomApplicationInsightsConfigBuilder("some-name", typeof(StringHelper));
+
+        // Act
+        var actualConfig = builder.Build();
+
+        // Assert
+        var expectedConfig =
+            new CustomApplicationInsightsConfig("some-name", typeof(StringHelper), DefaultConfigurationSectionName);
+        actualConfig.Should().BeEquivalentTo(expectedConfig);
+    }
+
+    [Fact]
+    public void GivenApplicationNameNotProvided_ThenDontSetApplicationName()
+    {
+        // Arrange
+        var builder = new CustomApplicationInsightsConfigBuilder(typeof(StringHelper));
+
+        // Act
+        var actualConfig = builder.Build();
+
+        // Assert
+        var expectedConfig =
+            new CustomApplicationInsightsConfig(applicationName: null, typeof(StringHelper),
+                DefaultConfigurationSectionName);
+        actualConfig.Should().BeEquivalentTo(expectedConfig);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData(" ")]
+    public void GivenEmptyOrWhiteSpaceSectionConfigurationName_ThenThrows(string configurationSectionName)
+    {
+        // Arrange
+        var builder = new CustomApplicationInsightsConfigBuilder("some-name", typeof(StringHelper));
+
+        // Act & Assert
+        Assert.ThrowsAny<Exception>(() => builder.WithConfigurationSectionName(configurationSectionName));
+    }
+}

tests/AzureFunctionsTelemetryTests/ApplicationInsights/CustomApplicationInsightsOptionsTests.cs renamed to tests/AzureFunctionsTelemetryTests/ApplicationInsights/CustomApplicationInsightsConfigTests.cs

@@ -1,17 +1,17 @@
 namespace Gabo.AzureFunctionsTelemetryTests.ApplicationInsights;
 
-public class CustomApplicationInsightsOptionsTests
+public class CustomApplicationInsightsConfigTests
 {
     [Theory]
     [InlineData("")]
     [InlineData(" ")]
-    public void GivenEmptyOrWhiteSpaceConfigurationSectionName_ThenThrows(string functionName)
+    public void GivenEmptyOrWhiteSpaceConfigurationSectionName_ThenThrows(string configurationSectionName)
     {
         // Act & Assert
         Assert.ThrowsAny<Exception>(() =>
             new CustomApplicationInsightsConfig(
                 "some-name",
                 typeof(StringHelper),
-                configurationSectionName: functionName));
+                configurationSectionName));
     }
 }