Move endpoint resolution from interceptors to pipeline stage by S-Saranya1 · Pull Request #6820 · aws/aws-sdk-java-v2

S-Saranya1 · 2026-03-26T15:28:38Z

Motivation and Context

The SDK uses ExecutionInterceptor for core endpoint resolution functionality. But this interface was
designed for customer extensibility, not internal SDK. This is Part 2 of the core interceptors migration, following the auth scheme resolution refactoring in #6755.

Modifications

1. Codegen — generate resolveEndpoint() in client classes

SyncClientClass, AsyncClientClass: Added resolveEndpoint() method generation containing service-specific endpoint resolution logic (param building, rules engine call, host prefix, auth scheme signer properties, business metrics).
JsonProtocolSpec, QueryProtocolSpec, XmlProtocolSpec: Pass callback via ClientExecutionParams.withEndpointResolver().
BaseClientBuilderClass: Removed endpoint interceptors from built-in interceptors list.

2. Codegen — generate per-service EndpointResolverUtils

EndpointResolverUtilsSpec: New codegen spec generating a per-service utility class (e.g., DynamoDbEndpointResolverUtils) with static helpers extracted from the old interceptor - ruleParams(), context params, host prefix, auth scheme property copying, metrics. Per-service because it references service-specific types.
EndpointRulesSpecUtils: Added helper methods for class name resolution.
EndpointProviderTasks: Generate EndpointResolverUtils instead of old interceptors.

3. Added EndpointResolutionStage

New pipeline stage in sdk-core that runs after AuthSchemeResolutionStage. Calls the service-specific callback, stores RESOLVED_ENDPOINT, copies endpoint headers, applies resolved URL, and reports ENDPOINT_RESOLVE_DURATION metric. Registered in both sync and async pipelines.

4. Added EndpointResolver interface and ClientExecutionParams

EndpointResolver functional interface in sdk-core, endpointResolver field on ClientExecutionParams, ENDPOINT_RESOLVER execution attribute, and wiring in AwsExecutionContextBuilder.

5. De-duplicated AwsEndpointProviderUtils

Created single shared class in aws-core replacing identical per-service generated copies. Deleted the AwsEndpointProviderUtils.java.resource template.

6. Updated S3 presigner and S3Utilities

Removed old endpoint interceptors from both. Added direct endpoint resolution methods that call S3EndpointResolverUtils.ruleParams() and apply the resolved URL.

7. Deleted dead code

Removed EndpointResolverInterceptorSpec, RequestEndpointInterceptorSpec, AuthSchemeInterceptorSpec, their tests, AwsEndpointProviderUtils.java.resource template, and dead generateAuthSchemeInterceptor() method.

Testing

Added EndpointResolutionStageTest - unit tests for the new pipeline stage
Verified existing functional tests for endpoint resolution behavior passing.
Modified codegen-fixture tests.

Screenshots (if appropriate)

Types of changes

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)

Checklist

I have read the CONTRIBUTING document
Local run of mvn install succeeds
My code follows the code style of this project
My change requires a change to the Javadoc documentation
I have updated the Javadoc documentation accordingly
I have added tests to cover my changes
All new and existing tests passed
I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

I confirm that this pull request can be released under the Apache 2 license

…l/endpoint-resolution-refactoring

Fred1155 · 2026-03-30T16:46:51Z

.../java/software/amazon/awssdk/core/internal/http/pipeline/stages/EndpointResolutionStage.java

+        }
+
+        // Apply resolved endpoint URL
+        ClientEndpointProvider clientEndpointProvider =


I see that in the design doc, there's a backward compatibility issue and is solved by adding a check for customer modified url here. Why is that missed here?

Fred1155 · 2026-03-30T17:01:05Z

codegen/src/main/java/software/amazon/awssdk/codegen/poet/client/ClientClassUtils.java

+                               awsV4aAuthScheme, awsV4aHttpSigner);
+            b.addStatement("$T optionBuilder = selectedAuthScheme.authSchemeOption().toBuilder()",
+                           authSchemeOption.nestedClass("Builder"));
+            b.addStatement("$1T rs = $1T.create(endpointParams.region().id())", regionSet);


Do we need to add a null check here for the endpointParams.region() here?

Nvm, seems that this won't be null

Fred1155 · 2026-03-30T18:07:10Z

...rc/main/java/software/amazon/awssdk/awscore/internal/endpoints/AwsEndpointProviderUtils.java

        return executionAttributes.getAttribute(AwsExecutionAttribute.FIPS_ENDPOINT_ENABLED);
    }

-    /**


Just curious why do we deleted the comments here and below?

+1, I think the comments provide some value, it's not super obvious what's happening

Fred1155 · 2026-03-30T18:18:00Z

...rc/test/java/software/amazon/awssdk/services/endpointproviders/EndpointInterceptorTests.java

                                                                                                              "TestValue0"))))
            .hasMessageContaining("stop");

-        assertThat(interceptor.context.httpRequest().matchingHeaders("TestHeader")).containsExactly("TestValue", "TestValue0");


This is a subtle behavioral change and we can call it out as a known behavior change in the feature branch merging PR description. if downstream system is doing exact string matching on header value ordering (which is wrong) this could break them.

dagnir · 2026-04-06T23:05:41Z

codegen/src/main/java/software/amazon/awssdk/codegen/poet/client/SyncClientClass.java

Ditto here, we need codegen tests

dagnir · 2026-04-06T23:07:32Z

...rc/main/java/software/amazon/awssdk/awscore/internal/endpoints/AwsEndpointProviderUtils.java

+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.awscore.internal.endpoints;


Is this being used across modules? If so, it shouldn't be internal

dagnir · 2026-04-06T23:08:32Z

...rc/main/java/software/amazon/awssdk/awscore/internal/endpoints/AwsEndpointProviderUtils.java

@@ -38,10 +52,6 @@ public static Boolean fipsEnabledBuiltIn(ExecutionAttributes executionAttributes
        return executionAttributes.getAttribute(AwsExecutionAttribute.FIPS_ENDPOINT_ENABLED);
    }

-    /**


+1, I think the comments provide some value, it's not super obvious what's happening

dagnir · 2026-04-06T23:11:10Z

.../java/software/amazon/awssdk/core/internal/http/pipeline/stages/EndpointResolutionStage.java

+        }
+
+        EndpointResolver resolver = attrs.getAttribute(SdkInternalExecutionAttribute.ENDPOINT_RESOLVER);
+        if (resolver == null) {


Is there a valid case where there's no resolver?

dagnir · 2026-04-06T23:15:22Z

codegen/src/main/java/software/amazon/awssdk/codegen/poet/client/ClientClassUtils.java

+        ClassName awsEndpointAttribute = ClassName.get("software.amazon.awssdk.awscore.endpoints", "AwsEndpointAttribute");
+        ClassName endpointAuthScheme = ClassName.get("software.amazon.awssdk.awscore.endpoints.authscheme", "EndpointAuthScheme");


Is this necessary? codegen has a dependency on aws-core so you should be able to reference the class directly

alextwoods · 2026-04-07T15:37:14Z

codegen/src/main/java/software/amazon/awssdk/codegen/poet/client/specs/JsonProtocolSpec.java

               .add(".withMetricCollector(apiCallMetricCollector)\n")
               .add(".withAuthSchemeOptionsResolver(r -> resolveAuthSchemeOptions(r, $S, clientConfiguration))\n",
                    opModel.getOperationName())
+               .add(".withEndpointResolver((r, a) -> resolveEndpoint(r, a, $S))\n",


This is beyond the scope of this PR, but it feels pretty weird that we need to specify the endpoint resolver (and auth scheme, metrics, ect) in protocol specific generation - these should be consistent across our protocols. (but again, this is beyond the scope of this PR, I don't think we need to refactor now....)

alextwoods · 2026-04-07T15:48:14Z

codegen/src/main/java/software/amazon/awssdk/codegen/poet/rules/EndpointResolverUtilsSpec.java

+/**
+ * Generates a per-service endpoint resolver utility class (e.g. {@code DynamoDbEndpointResolverUtils})
+ * containing all static helper methods for endpoint resolution: building endpoint params, host prefix
+ * resolution, auth scheme property copying, and business metrics.


Do we need to code generate this at all? What service specific logic does it have vs what is generic? If its generic, I'd lean towards moving it out of our codegeneration and into a core package. That makes codegen simpler, reduces duplication between services (reducing artifact size) and makes it easier to unit test.

alextwoods · 2026-04-07T16:00:03Z

...rc/main/java/software/amazon/awssdk/awscore/internal/endpoints/AwsEndpointProviderUtils.java

This could use some Unit tests

alextwoods · 2026-04-07T16:28:56Z

core/sdk-core/src/main/java/software/amazon/awssdk/core/spi/endpoint/EndpointResolver.java

+ * Callback interface for resolving endpoints from the request and execution context.
+ */
+@FunctionalInterface
+@SdkProtectedApi


Should this be a public API? Its in the SPI module and seems potentially like something we should support as a public interface?

If not, then I think this should probalby be moved out of spi/endpoint

S-Saranya1 requested a review from a team as a code owner March 26, 2026 15:28

S-Saranya1 force-pushed the somepal/endpoint-resolution-refactoring branch from 87d0960 to 305ba3a Compare March 27, 2026 16:38

Move endpoint resolution from interceptors to pipeline stage

7b09efe

S-Saranya1 force-pushed the somepal/endpoint-resolution-refactoring branch from 6000d9f to 7b09efe Compare March 27, 2026 17:15

Merge branch 'feature/master/core-interceptors-migration' into somepa…

77abd70

…l/endpoint-resolution-refactoring

Fred1155 reviewed Mar 30, 2026

View reviewed changes

dagnir requested changes Apr 6, 2026

View reviewed changes

alextwoods reviewed Apr 7, 2026

View reviewed changes

		ClassName awsEndpointAttribute = ClassName.get("software.amazon.awssdk.awscore.endpoints", "AwsEndpointAttribute");
		ClassName endpointAuthScheme = ClassName.get("software.amazon.awssdk.awscore.endpoints.authscheme", "EndpointAuthScheme");

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S-Saranya1 commented Mar 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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S-Saranya1 commented Mar 26, 2026 •

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