When using DistributedApplicationTestingBuilder, how to force configuration on the app host?

[paulomorgado]

On my app host, depending on the configuration, I launch different resources or have different configurations for the resources.

How can I change the configuration of the app host when invoking DistributedApplicationTestingBuilder.CreateAsync, other than setting environment variables?

[paulomorgado]

Got it working with:

var builder = await DistributedApplicationTestingBuilder.CreateAsync<Projects.Connector_Aspire_AppHost>(
    args: [
        "--myconfig=myvalue",
    ]);

By the way, this ends up setting up several instances of CommandLineConfigurationProvider with duplicate items. Is this expected?

<title>Document</title>

	Name	Value	Type
◢	_sources	{Microsoft.Extensions.Configuration.ConfigurationManager.ConfigurationSources}	Microsoft.Extensions.Configuration.ConfigurationManager.ConfigurationSources
	Count	12	int
	IsReadOnly	false	bool
	▶ _config	Sections = 224	Microsoft.Extensions.Configuration.ConfigurationManager
	◢ _sources	Count = 12	System.Collections.Generic.List<Microsoft.Extensions.Configuration.IConfigurationSource>
	▶ [0]	{Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}
	▶ [1]	{Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}
	▶ [2]	{Microsoft.Extensions.Configuration.EnvironmentVariables.EnvironmentVariablesConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.EnvironmentVariables.EnvironmentVariablesConfigurationSource}
	◢ [3]	{Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}
	◢ Args	{string[2]}	System.Collections.Generic.IEnumerable {string[]}
	[0]	"--myconfig=myvalue"	string
	[1]	"--myconfig=myvalue"	string
	SwitchMappings	null	System.Collections.Generic.IDictionary<string, string>
	▶ [4]	{Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}
	▶ [5]	{Microsoft.Extensions.Configuration.Json.JsonConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Json.JsonConfigurationSource}
	▶ [6]	{Microsoft.Extensions.Configuration.Json.JsonConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Json.JsonConfigurationSource}
	▶ [7]	{Microsoft.Extensions.Configuration.EnvironmentVariables.EnvironmentVariablesConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.EnvironmentVariables.EnvironmentVariablesConfigurationSource}
	◢ [8]	{Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}
	◢ Args	{string[2]}	System.Collections.Generic.IEnumerable {string[]}
	[0]	"--myconfig=myvalue"	string
	[1]	"--myconfig=myvalue"	string
	SwitchMappings	null	System.Collections.Generic.IDictionary<string, string>
	◢ [9]	{Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.CommandLine.CommandLineConfigurationSource}
	◢ Args	{string[2]}	System.Collections.Generic.IEnumerable {string[]}
	[0]	"--myconfig=myvalue"	string
	[1]	"--myconfig=myvalue"	string
	▶ SwitchMappings	Count = 6	System.Collections.Generic.IDictionary<string, string> {System.Collections.Generic.Dictionary<string, string>}
	▶ [10]	{Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}
	▶ [11]	{Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}	Microsoft.Extensions.Configuration.IConfigurationSource {Microsoft.Extensions.Configuration.Memory.MemoryConfigurationSource}