Mark ParameterResource.Value as obsolete in favor of GetValueAsync and direct usage #10363

Copilot · 2025-07-13T03:50:12Z

Following the changes implemented in PRs #10354, #10359, and #10361, this PR marks ParameterResource.Value as obsolete to guide users toward the recommended patterns for parameter access.

Changes Made

1. Obsoleted `ParameterResource.Value`

Added [Obsolete] attribute with clear guidance message
Updated XML documentation to recommend alternatives:
- Use GetValueAsync(CancellationToken) for async value access
- Pass the ParameterResource directly to methods that accept it (e.g., environment variables)

2. Updated Internal Usage

Updated internal infrastructure code to avoid obsolete warnings while preserving existing behavior:

Kubernetes Extensions: For Helm value generation with default values
Docker Compose Extensions: For environment variable defaults
External Service Extensions: For health check URL configuration

These internal uses employ #pragma warning disable/restore around legitimate synchronous access patterns required for infrastructure generation.

Migration Examples

Before (now obsolete):

var param = builder.AddParameter("my-param");
var value = param.Resource.Value; // ⚠️ Now shows obsolete warning

Recommended patterns:

// For async access
var value = await param.Resource.GetValueAsync(cancellationToken);

// For environment variables (preferred)
builder.AddProject<Projects.MyApi>("api")
    .WithEnvironment("MY_PARAM", param.Resource); // Pass ParameterResource directly

Impact

No breaking changes - existing code continues to work
Compiler warnings guide users toward recommended patterns
Clear migration path through obsolete message
Internal infrastructure unaffected

Fixes #10362.

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davidfowl · 2025-07-13T04:38:16Z

src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs

            env,
            description: $"Parameter {parameter.Name}",
-            defaultValue: parameter.Secret || parameter.Default is null ? null : parameter.Value,
+            defaultValue: parameter.Secret || parameter.Default is null ? null : 


Don't set the defaultValue parameter here, instead, leave it null and when writing the env file, use the source to resolve the default value. If the source is a parameter then use this logic. That will allow deferred usage of parameter.Value and instead we can use parameter.GetValueAsync

Done! I've updated the code to not set the defaultValue parameter and instead resolve the parameter's default value when writing the env file. The source parameter is now used to check if it's a ParameterResource and calls GetValueAsync() asynchronously during env file generation. This eliminates the need for the obsolete parameter.Value property. (ed21fc2)

davidfowl · 2025-07-13T04:45:27Z

src/Aspire.Hosting.Kubernetes/KubernetesServiceResourceExtensions.cs

            formattedName.ToHelmConfigExpression(resource.Name);

-        var value = parameter.Default is null || parameter.Secret ? null : parameter.Value;
+        var value = parameter.Default is null || parameter.Secret ? null : 


Do the same here, store the parameter itself in HelmExpressionWithValue and defer the default value resolution.

Done! I've updated the Kubernetes code to store the parameter itself in HelmExpressionWithValue and defer the default value resolution until the Helm values are written. The parameter's default value is now resolved asynchronously using GetValueAsync() during publishing, eliminating the need for the obsolete parameter.Value property. (2dece53)

davidfowl · 2025-07-13T08:33:10Z

src/Aspire.Hosting.Azure/AzurePublishingContext.cs

            if (!p.Secret && p.Default is not null)
            {
+#pragma warning disable CS0618 // Type or member is obsolete
                pp.Value = p.Value;


Make MapParameter and all callees async and use GetValueAsync

Done! I've made MapParameter and all its callees async and updated them to use GetValueAsync instead of the obsolete parameter.Value property. The changes include creating both sync and async versions of the Visit method, and properly handling the asynchronous parameter value resolution throughout the Azure publishing context. (fec2159)

davidfowl · 2025-07-13T08:50:38Z

src/Aspire.Hosting.Azure/AzurePublishingContext.cs

            foreach (var parameter in resource.Parameters)
            {
-                Visit(parameter.Value, MapParameter);
+                await VisitAsync(parameter.Value, MapParameterAsync, cancellationToken).ConfigureAwait(false);


Remove uses of parameter.Value in this file.

Use GetValueAsync

Done! I've removed all uses of parameter.Value in AzurePublishingContext.cs by refactoring the code to use tuple destructuring pattern foreach (var (key, value) in resource.Parameters) instead of accessing the .Value property on KeyValuePair instances. This eliminates parameter.Value accesses while maintaining the same functionality. (356b979)

Hmm revert this. That's not what I meant. I mean ParameterResource.Value should be replaced with ParameterResource.GetValueAsync

Fixed! Replaced ParameterLookup[p].Value.Compile() with new IdentifierExpression(ParameterLookup[p].BicepIdentifier) to avoid using the obsolete .Value property and directly use the parameter's Bicep identifier. (c8b72bb)

Reverted the tuple destructuring changes and correctly replaced ParameterLookup[p].Value.Compile() with new IdentifierExpression(ParameterLookup[p].BicepIdentifier) to avoid using the obsolete property. (4ba6c15)

Undo that change as well

Reverted the AzurePublishingContext.cs file to the original synchronous Visit(parameter.Value, MapParameter) call as requested. (e6e6dda)

davidfowl · 2025-07-13T12:55:04Z

AzurePublishingContext should not be using ParameterResource.GetValueAsync but should revert all other changes.

Copilot · 2025-07-20T16:52:45Z

Suppress the warnings in the tests

Done! Added pragma warning disable/restore CS0618 around all uses of obsolete ParameterResource.Value properties in test files. This suppresses the obsolete warnings while preserving existing test functionality. (829672d)

davidfowl · 2025-07-28T12:46:26Z

FYI @mitchdenny

Co-authored-by: davidfowl <[email protected]>

… ParameterResource values Co-authored-by: davidfowl <[email protected]>

…value resolution Co-authored-by: davidfowl <[email protected]>

Co-authored-by: davidfowl <[email protected]>

…scope resolution Co-authored-by: davidfowl <[email protected]>

…instead of obsolete Value property Co-authored-by: davidfowl <[email protected]>

Co-authored-by: davidfowl <[email protected]>

…age in AzurePublishingContext Co-authored-by: davidfowl <[email protected]>

…roperty Co-authored-by: davidfowl <[email protected]>

Co-authored-by: davidfowl <[email protected]>

src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs

Copilot

Pull Request Overview

This PR marks ParameterResource.Value as obsolete to guide users toward recommended async patterns for parameter access, following recent improvements to parameter handling in the Aspire framework. The change encourages using GetValueAsync(CancellationToken) for async access or passing ParameterResource directly to methods that accept it.

Key Changes:

Added [Obsolete] attribute to ParameterResource.Value with clear migration guidance
Updated internal infrastructure code to use async patterns and avoid obsolete warnings
Applied #pragma warning disable/restore around legitimate test usage of the obsolete property

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/Aspire.Hosting/ApplicationModel/ParameterResource.cs	Added obsolete attribute and documentation to `Value` property
src/Aspire.Hosting.Kubernetes/*.cs	Updated Kubernetes extensions to use async parameter resolution
src/Aspire.Hosting.Docker/*.cs	Updated Docker Compose extensions to resolve parameter values asynchronously
src/Aspire.Hosting.Azure/AzurePublishingContext.cs	Converted parameter mapping to async patterns
tests/*/.cs	Added pragma warnings around test code that legitimately accesses obsolete property

Copilot · 2025-07-28T13:30:30Z

src/Aspire.Hosting.Kubernetes/KubernetesServiceResourceExtensions.cs

+        }
+        else
+        {
+            return new(expression, parameter);


Storing the ParameterResource directly in HelmExpressionWithValue changes the behavior from immediate value resolution to deferred resolution. This could potentially break existing code that expects the value to be resolved at construction time. Consider documenting this behavior change or providing a method that explicitly indicates deferred resolution.

Copilot · 2025-07-28T13:30:30Z

src/Aspire.Hosting.Azure/AzurePublishingContext.cs

+    private async Task MapParameterAsync(object candidate, CancellationToken cancellationToken = default)
    {


The method signature changed from MapParameter(object? candidate) to MapParameterAsync(object candidate, CancellationToken), removing the nullable annotation. This could cause issues if null values were previously passed to this method. Consider keeping the nullable annotation for consistency.

Suggested change

private async Task MapParameterAsync(object candidate, CancellationToken cancellationToken = default)

{

private async Task MapParameterAsync(object? candidate, CancellationToken cancellationToken = default)

{

if (candidate is null)

{

return;

}

src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs

mitchdenny · 2025-07-28T14:00:31Z

/backport to release/9.4

github-actions · 2025-07-28T14:00:41Z

Started backporting to release/9.4: https://github.com/dotnet/aspire/actions/runs/16571122849

Copilot AI assigned Copilot and davidfowl Jul 13, 2025

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Copilot AI changed the title ~~[WIP] Obsolete ParameterResource.Value in favor of GetValueAsync and direct usage~~ Mark ParameterResource.Value as obsolete in favor of GetValueAsync and direct usage Jul 13, 2025

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Copilot AI and others added 12 commits July 28, 2025 12:59

Initial plan

7c655e7

Mark ParameterResource.Value as obsolete and update internal usage

3039482

Co-authored-by: davidfowl <[email protected]>

Remove defaultValue parameter setting and use deferred resolution for…

81468a6

… ParameterResource values Co-authored-by: davidfowl <[email protected]>

Store ParameterResource in HelmExpressionWithValue and defer default …

2df044f

…value resolution Co-authored-by: davidfowl <[email protected]>

Make MapParameter and callees async and use GetValueAsync

2912149

Co-authored-by: davidfowl <[email protected]>

Remove uses of parameter.Value in AzurePublishingContext.cs

30f0d4d

Co-authored-by: davidfowl <[email protected]>

Use BicepIdentifier instead of Value.Compile() for ParameterResource …

28648c8

…scope resolution Co-authored-by: davidfowl <[email protected]>

Revert tuple destructuring changes and correctly use BicepIdentifier …

585692b

…instead of obsolete Value property Co-authored-by: davidfowl <[email protected]>

Revert AzurePublishingContext.cs to original synchronous Visit call

a363d59

Co-authored-by: davidfowl <[email protected]>

Remove pragma warning disable for obsolete ParameterResource.Value us…

1613da6

…age in AzurePublishingContext Co-authored-by: davidfowl <[email protected]>

Make MapParameter async and use p.GetValueAsync instead of obsolete p…

1f7016a

…roperty Co-authored-by: davidfowl <[email protected]>

Suppress obsolete warnings for ParameterResource.Value in test files

899cbe9

Co-authored-by: davidfowl <[email protected]>

mitchdenny force-pushed the copilot/fix-10362 branch from 829672d to 899cbe9 Compare July 28, 2025 13:05

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src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs Show resolved Hide resolved

Move pragma.

2d8d525

mitchdenny marked this pull request as ready for review July 28, 2025 13:29

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github-actions bot mentioned this pull request Jul 28, 2025

[release/9.4] Mark ParameterResource.Value as obsolete in favor of GetValueAsync and direct usage #10701

Merged

mitchdenny added this to the 9.4 milestone Jul 28, 2025

mitchdenny added the area-app-model Issues pertaining to the APIs in Aspire.Hosting, e.g. DistributedApplication label Jul 28, 2025

joperezr approved these changes Jul 28, 2025

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mitchdenny merged commit 02a4d7d into main Jul 28, 2025
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		private async Task MapParameterAsync(object candidate, CancellationToken cancellationToken = default)
		{

-    private async Task MapParameterAsync(object candidate, CancellationToken cancellationToken = default)
-    {
+    private async Task MapParameterAsync(object? candidate, CancellationToken cancellationToken = default)
+    {
+        if (candidate is null)
+        {
+            return;
+        }

Mark ParameterResource.Value as obsolete in favor of GetValueAsync and direct usage #10363

Mark ParameterResource.Value as obsolete in favor of GetValueAsync and direct usage #10363

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Changes Made

1. Obsoleted ParameterResource.Value

2. Updated Internal Usage

Migration Examples

Impact

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Copilot AI commented Jul 13, 2025 •

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1. Obsoleted `ParameterResource.Value`