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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Aspire.Hosting.ApplicationModel;
using Aspire.Hosting.Lifecycle;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
namespace Aspire.Hosting;
/// <summary>
/// Provides extension methods for adding parameter resources to an application.
/// </summary>
public static class ParameterResourceBuilderExtensions
{
/// <summary>
/// Adds a parameter resource to the application.
/// </summary>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource</param>
/// <param name="secret">Optional flag indicating whether the parameter should be regarded as secret.</param>
/// <returns>Resource builder for the parameter.</returns>
/// <exception cref="DistributedApplicationException"></exception>
public static IResourceBuilder<ParameterResource> AddParameter(this IDistributedApplicationBuilder builder, string name, bool secret = false)
{
return builder.AddParameter(name, parameterDefault => GetParameterValue(builder.Configuration, name, parameterDefault), secret: secret);
}
/// <summary>
/// Adds a parameter resource to the application with a given value.
/// </summary>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource</param>
/// <param name="value">A string value to use for the paramater</param>
/// <param name="secret">Optional flag indicating whether the parameter should be regarded as secret.</param>
/// <returns>Resource builder for the parameter.</returns>
[System.Diagnostics.CodeAnalysis.SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters",
Justification = "third parameters are mutually exclusive.")]
public static IResourceBuilder<ParameterResource> AddParameter(this IDistributedApplicationBuilder builder, string name, string value, bool secret = false)
{
// An alternate implementation is to use some ConstantParameterDefault implementation that always returns the default value.
// However, doing this causes a "default": {} to be written to the manifest, which is not valid.
// And note that we ignore parameterDefault in the callback, because it can never be non-null, and we want our own value.
return builder.AddParameter(name, parameterDefault => value, secret: secret);
}
/// <summary>
/// Adds a parameter resource to the application, with a value coming from a ParameterDefault.
/// </summary>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource</param>
/// <param name="value">A <see cref="ParameterDefault"/> that is used to provide the parameter value</param>
/// <param name="secret">Optional flag indicating whether the parameter should be regarded as secret.</param>
/// <param name="persist">Persist the value to the app host project's user secrets store. This is typically
/// done when the value is generated, so that it stays stable across runs. This is only relevant when
/// <see cref="DistributedApplicationExecutionContext.IsRunMode"/> is <c>true</c>
/// </param>
/// <returns>Resource builder for the parameter.</returns>
[System.Diagnostics.CodeAnalysis.SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters",
Justification = "third parameters are mutually exclusive.")]
public static IResourceBuilder<ParameterResource> AddParameter(this IDistributedApplicationBuilder builder, string name, ParameterDefault value, bool secret = false, bool persist = false)
{
// If it needs persistence, wrap it in a UserSecretsParameterDefault
if (persist && builder.ExecutionContext.IsRunMode && builder.AppHostAssembly is not null)
{
value = new UserSecretsParameterDefault(builder.AppHostAssembly, builder.Environment.ApplicationName, name, value);
}
return builder.AddParameter(
name,
parameterDefault => parameterDefault!.GetDefaultValue(),
secret: secret,
parameterDefault: value);
}
private static string GetParameterValue(IConfiguration configuration, string name, ParameterDefault? parameterDefault)
{
var configurationKey = $"Parameters:{name}";
return configuration[configurationKey]
?? parameterDefault?.GetDefaultValue()
?? throw new DistributedApplicationException($"Parameter resource could not be used because configuration key '{configurationKey}' is missing and the Parameter has no default value."); ;
}
internal static IResourceBuilder<ParameterResource> AddParameter(this IDistributedApplicationBuilder builder,
string name,
Func<ParameterDefault?, string> callback,
bool secret = false,
bool connectionString = false,
ParameterDefault? parameterDefault = null)
{
var resource = new ParameterResource(name, callback, secret);
resource.IsConnectionString = connectionString;
resource.Default = parameterDefault;
var state = new CustomResourceSnapshot()
{
ResourceType = "Parameter",
// hide parameters by default
State = KnownResourceStates.Hidden,
Properties = [
new("parameter.secret", secret.ToString()),
new(CustomResourceKnownProperties.Source, connectionString ? $"ConnectionStrings:{name}" : $"Parameters:{name}")
]
};
try
{
state = state with { Properties = [.. state.Properties, new("Value", resource.Value)] };
}
catch (DistributedApplicationException ex)
{
state = state with
{
State = new ResourceStateSnapshot("Configuration missing", KnownResourceStateStyles.Error),
Properties = [.. state.Properties, new("Value", ex.Message)]
};
builder.Services.AddLifecycleHook((sp) => new WriteParameterLogsHook(
sp.GetRequiredService<ResourceLoggerService>(),
name,
ex.Message));
}
return builder.AddResource(resource)
.WithInitialState(state);
}
/// <summary>
/// Writes the message to the specified resource's logs.
/// </summary>
private sealed class WriteParameterLogsHook(ResourceLoggerService loggerService, string resourceName, string message) : IDistributedApplicationLifecycleHook
{
public Task BeforeStartAsync(DistributedApplicationModel appModel, CancellationToken cancellationToken)
{
loggerService.GetLogger(resourceName).LogError(message);
return Task.CompletedTask;
}
}
/// <summary>
/// Adds a parameter to the distributed application but wrapped in a resource with a connection string for use with <see cref="ResourceBuilderExtensions.WithReference{TDestination}(IResourceBuilder{TDestination}, IResourceBuilder{IResourceWithConnectionString}, string?, bool)"/>
/// </summary>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource. The value of the connection string is read from the "ConnectionStrings:{resourcename}" configuration section, for example in appsettings.json or user secrets</param>
/// <param name="environmentVariableName">Environment variable name to set when WithReference is used.</param>
/// <returns>Resource builder for the parameter.</returns>
/// <exception cref="DistributedApplicationException"></exception>
public static IResourceBuilder<IResourceWithConnectionString> AddConnectionString(this IDistributedApplicationBuilder builder, string name, string? environmentVariableName = null)
{
var parameterBuilder = builder.AddParameter(name, _ =>
{
return builder.Configuration.GetConnectionString(name) ?? throw new DistributedApplicationException($"Connection string parameter resource could not be used because connection string '{name}' is missing.");
},
secret: true,
connectionString: true);
var surrogate = new ResourceWithConnectionStringSurrogate(parameterBuilder.Resource, environmentVariableName);
return builder.CreateResourceBuilder(surrogate);
}
/// <summary>
/// Changes the resource to be published as a connection string reference in the manifest.
/// </summary>
/// <typeparam name="T">The resource type.</typeparam>
/// <param name="builder">The resource builder.</param>
/// <returns>The configured <see cref="IResourceBuilder{T}"/>.</returns>
public static IResourceBuilder<T> PublishAsConnectionString<T>(this IResourceBuilder<T> builder)
where T : ContainerResource, IResourceWithConnectionString
{
ConfigureConnectionStringManifestPublisher(builder);
return builder;
}
/// <summary>
/// Configures the manifest writer for this resource to be a parameter resource.
/// </summary>
/// <param name="builder">The <see cref="IResourceBuilder{T}"/>.</param>
public static void ConfigureConnectionStringManifestPublisher(IResourceBuilder<IResourceWithConnectionString> builder)
{
// Create a parameter resource that we use to write to the manifest
var parameter = new ParameterResource(builder.Resource.Name, _ => "", secret: true);
parameter.IsConnectionString = true;
builder.WithManifestPublishingCallback(context => context.WriteParameterAsync(parameter));
}
/// <summary>
/// Creates a default password parameter that generates a random password.
/// </summary>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource</param>
/// <param name="lower"><see langword="true" /> if lowercase alphabet characters should be included; otherwise, <see langword="false" />.</param>
/// <param name="upper"><see langword="true" /> if uppercase alphabet characters should be included; otherwise, <see langword="false" />.</param>
/// <param name="numeric"><see langword="true" /> if numeric characters should be included; otherwise, <see langword="false" />.</param>
/// <param name="special"><see langword="true" /> if special characters should be included; otherwise, <see langword="false" />.</param>
/// <param name="minLower">The minimum number of lowercase characters in the result.</param>
/// <param name="minUpper">The minimum number of uppercase characters in the result.</param>
/// <param name="minNumeric">The minimum number of numeric characters in the result.</param>
/// <param name="minSpecial">The minimum number of special characters in the result.</param>
/// <returns>The created <see cref="ParameterResource"/>.</returns>
/// <remarks>
/// To ensure the generated password has enough entropy, see the remarks in <see cref="GenerateParameterDefault"/>.<br/>
/// The value will be saved to the app host project's user secrets store when <see cref="DistributedApplicationExecutionContext.IsRunMode"/> is <c>true</c>.
/// </remarks>
public static ParameterResource CreateDefaultPasswordParameter(
IDistributedApplicationBuilder builder, string name,
bool lower = true, bool upper = true, bool numeric = true, bool special = true,
int minLower = 0, int minUpper = 0, int minNumeric = 0, int minSpecial = 0)
{
var generatedPassword = new GenerateParameterDefault
{
MinLength = 22, // enough to give 128 bits of entropy when using the default 67 possible characters. See remarks in GenerateParameterDefault
Lower = lower,
Upper = upper,
Numeric = numeric,
Special = special,
MinLower = minLower,
MinUpper = minUpper,
MinNumeric = minNumeric,
MinSpecial = minSpecial
};
return CreateGeneratedParameter(builder, name, secret: true, generatedPassword);
}
/// <summary>
/// Creates a new <see cref="ParameterResource"/> that has a generated value using the <paramref name="parameterDefault"/>.
/// </summary>
/// <remarks>
/// The value will be saved to the app host project's user secrets store when <see cref="DistributedApplicationExecutionContext.IsRunMode"/> is <c>true</c>.
/// </remarks>
/// <param name="builder">Distributed application builder</param>
/// <param name="name">Name of parameter resource</param>
/// <param name="secret">Flag indicating whether the parameter should be regarded as secret.</param>
/// <param name="parameterDefault">The <see cref="GenerateParameterDefault"/> that describes how the parameter's value should be generated.</param>
/// <returns>The created <see cref="ParameterResource"/>.</returns>
public static ParameterResource CreateGeneratedParameter(
IDistributedApplicationBuilder builder, string name, bool secret, GenerateParameterDefault parameterDefault)
{
var parameterResource = new ParameterResource(name, defaultValue => GetParameterValue(builder.Configuration, name, defaultValue), secret)
{
Default = parameterDefault
};
if (builder.ExecutionContext.IsRunMode && builder.AppHostAssembly is not null)
{
parameterResource.Default = new UserSecretsParameterDefault(builder.AppHostAssembly, builder.Environment.ApplicationName, name, parameterResource.Default);
}
return parameterResource;
}
}
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