generate auth params and bindings

codegen/smithy-go-codegen/build.gradle.kts

@@ -21,6 +21,7 @@ extra["moduleName"] = "software.amazon.smithy.go.codegen"
 
 dependencies {
     api("software.amazon.smithy:smithy-codegen-core:$smithyVersion")
+    api("software.amazon.smithy:smithy-aws-traits:$smithyVersion")
     implementation("software.amazon.smithy:smithy-waiters:$smithyVersion")
     api("com.atlassian.commonmark:commonmark:0.15.2")
     api("org.jsoup:jsoup:1.14.1")

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/CodegenVisitor.java

@@ -247,6 +247,11 @@ void execute() {
                 protocolGenerator.generateEndpointResolution(context);
             });
 
+            writers.useFileWriter("auth.go", settings.getModuleName(), writer -> {
+                ProtocolGenerator.GenerationContext context = contextBuilder.writer(writer).build();
+                protocolGenerator.generateAuth(context);
+            });
+
             writers.useFileWriter("endpoints_test.go", settings.getModuleName(), writer -> {
                 ProtocolGenerator.GenerationContext context = contextBuilder.writer(writer).build();
                 protocolGenerator.generateEndpointResolutionTests(context);

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/GoUniverseTypes.java

@@ -39,7 +39,7 @@ public final class GoUniverseTypes {
     public static Symbol tInt32 = universe("int32");
     public static Symbol tInt64 = universe("int64");
     public static Symbol tRune = universe("rune");
-    public static Symbol tString = universe("string");
+    public static final Symbol STRING = universe("string");
 
     public static Symbol tUint = universe("uint");
     public static Symbol tUint8 = universe("uint8");

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/OperationGenerator.java

@@ -130,6 +130,15 @@ public void run() {
                 .renderStructure(() -> {
                 }, true);
 
+        writer.write("""
+                            func (*$T) operationName() string {
+                                return $S
+                            }
+                            """,
+                inputSymbol,
+                operationSymbol.getName()
+        );
+
         // The output structure gets a metadata member added.
         Symbol metadataSymbol = SymbolUtils.createValueSymbolBuilder("Metadata", SmithyGoDependency.SMITHY_MIDDLEWARE)
                 .build();

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthGenerator.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.go.codegen.auth;
+
+import software.amazon.smithy.codegen.core.CodegenException;
+import software.amazon.smithy.go.codegen.integration.ProtocolGenerator;
+
+/**
+ * Entry point into smithy client auth generation.
+ */
+public class AuthGenerator {
+    private final ProtocolGenerator.GenerationContext context;
+
+    public AuthGenerator(ProtocolGenerator.GenerationContext context) {
+        this.context = context;
+    }
+
+    public void generate() {
+        if (context.getWriter().isEmpty()) {
+            throw new CodegenException("writer is required");
+        }
+
+        context.getWriter().get()
+                .write("$W", new AuthParametersGenerator(context).generate())
+                .write("")
+                .write("$W", new AuthParametersResolverGenerator(context).generate());
+    }
+}

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthParameter.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.go.codegen.auth;
+
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.go.codegen.GoUniverseTypes;
+
+public record AuthParameter(String name, String docs, Symbol type) {
+    public static final AuthParameter OPERATION = new AuthParameter(
+            "Operation",
+            "The name of the operation being invoked.",
+            GoUniverseTypes.STRING
+    );
+
+    public static final AuthParameter REGION = new AuthParameter(
+            "Region",
+            "The region in which the operation is being invoked.",
+            GoUniverseTypes.STRING
+    );
+}

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthParametersGenerator.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.go.codegen.auth;
+
+import static software.amazon.smithy.go.codegen.GoWriter.goDocTemplate;
+import static software.amazon.smithy.go.codegen.GoWriter.goTemplate;
+
+import java.util.ArrayList;
+import software.amazon.smithy.aws.traits.auth.SigV4Trait;
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.go.codegen.GoWriter;
+import software.amazon.smithy.go.codegen.SymbolUtils;
+import software.amazon.smithy.go.codegen.integration.ProtocolGenerator;
+import software.amazon.smithy.utils.ListUtils;
+import software.amazon.smithy.utils.MapUtils;
+
+/**
+ * Generates auth scheme resolver parameters.
+ * By default, the only field that exists universally is the name of the operation being invoked. Services that use
+ * SigV4[A] will also have a field for the region.
+ * Additional parameters can be loaded via GoIntegration.
+ */
+public class AuthParametersGenerator {
+    public static final String STRUCT_NAME = "AuthResolverParameters";
+
+    public static final Symbol STRUCT_SYMBOL = SymbolUtils.createPointableSymbolBuilder(STRUCT_NAME).build();
+
+    private final ProtocolGenerator.GenerationContext context;
+
+    private final ArrayList<AuthParameter> fields = new ArrayList<>(
+            ListUtils.of(AuthParameter.OPERATION)
+    );
+
+    public AuthParametersGenerator(ProtocolGenerator.GenerationContext context) {
+        this.context = context;
+    }
+
+    public GoWriter.Writable generate() {
+        loadFields();
+
+        return goTemplate(
+                """
+                        $doc:W
+                        type $name:L struct {
+                            $fields:W
+                        }
+                        """,
+                MapUtils.of(
+                        "doc", generateDocs(),
+                        "name", STRUCT_NAME,
+                        "fields", generateFields()
+                )
+        );
+    }
+
+    private GoWriter.Writable generateDocs() {
+        return goDocTemplate(
+                "$name:L contains the set of inputs necessary for auth scheme resolution.",
+                MapUtils.of("name", STRUCT_NAME)
+        );
+    }
+
+    private GoWriter.Writable generateFields() {
+        return (writer) -> {
+            for (var field: fields) {
+                writer.write("""
+                        $W
+                        $L $P
+                        """,
+                        goDocTemplate(field.docs()),
+                        field.name(),
+                        field.type()
+                );
+            }
+        };
+    }
+
+    private void loadFields() {
+        if (context.getService().hasTrait(SigV4Trait.class)) {
+            fields.add(AuthParameter.REGION);
+        }
+
+        for (var integration: context.getIntegrations()) {
+            var plugins = integration.getClientPlugins().stream().filter(it ->
+                    it.matchesService(context.getModel(), context.getService())).toList();
+            for (var plugin: plugins) {
+                fields.addAll(plugin.getAuthParameters());
+            }
+        }
+    }
+}

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthParametersResolver.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.go.codegen.auth;
+
+import software.amazon.smithy.codegen.core.Symbol;
+
+public record AuthParametersResolver(Symbol resolver) { }

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthParametersResolverGenerator.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.go.codegen.auth;
+
+import static software.amazon.smithy.go.codegen.GoWriter.goTemplate;
+
+import java.util.ArrayList;
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.go.codegen.GoWriter;
+import software.amazon.smithy.go.codegen.SymbolUtils;
+import software.amazon.smithy.go.codegen.integration.ProtocolGenerator;
+import software.amazon.smithy.utils.MapUtils;
+
+/**
+ * Generates a single method which binds auth scheme resolver parameters from operation input and client options.
+ * The only value bound by default is the operation name. Generators must load additional bindings through
+ * GoIntegration.
+ */
+public class AuthParametersResolverGenerator {
+    public static final String FUNC_NAME = "bindAuthResolverParams";
+
+    public static final Symbol FUNC_SYMBOL = SymbolUtils.createValueSymbolBuilder(FUNC_NAME).build();
+
+    private final ProtocolGenerator.GenerationContext context;
+
+    private final ArrayList<AuthParametersResolver> resolvers = new ArrayList<>();
+
+    public AuthParametersResolverGenerator(ProtocolGenerator.GenerationContext context) {
+        this.context = context;
+    }
+
+    public GoWriter.Writable generate() {
+        loadBindings();
+
+        var paramsSymbol = SymbolUtils.createPointableSymbolBuilder(AuthParametersGenerator.STRUCT_NAME).build();
+
+        return goTemplate("""
+                $operationNamer:W
+
+                func $name:L(input interface{}, options Options) $params:P {
+                    params := &$params:T{
+                        Operation: input.(operationNamer).operationName(),
+                    }
+
+                    $bindings:W
+
+                    return params
+                }
+                """,
+                MapUtils.of(
+                        "name", FUNC_NAME,
+                        "operationNamer", generateOperationNamer(),
+                        "params", paramsSymbol,
+                        "bindings", generateBindings()
+                ));
+    }
+
+    private GoWriter.Writable generateOperationNamer() {
+        return (writer) -> {
+            writer.write("""
+                    type operationNamer interface {
+                        operationName() string
+                    }
+                    """);
+        };
+    }
+
+    private GoWriter.Writable generateBindings() {
+        return (writer) -> {
+            for (var resolver: resolvers) {
+                writer.write("$T(params, input, options)", resolver.resolver());
+            }
+        };
+    }
+
+    private void loadBindings() {
+        for (var integration: context.getIntegrations()) {
+            var plugins = integration.getClientPlugins().stream().filter(it ->
+                    it.matchesService(context.getModel(), context.getService())).toList();
+            for (var plugin: plugins) {
+                resolvers.addAll(plugin.getAuthParameterResolvers());
+            }
+        }
+    }
+}

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/ProtocolGenerator.java

@@ -29,6 +29,7 @@
 import software.amazon.smithy.go.codegen.GoSettings;
 import software.amazon.smithy.go.codegen.GoWriter;
 import software.amazon.smithy.go.codegen.Synthetic;
+import software.amazon.smithy.go.codegen.auth.AuthGenerator;
 import software.amazon.smithy.go.codegen.endpoints.EndpointResolutionGenerator;
 import software.amazon.smithy.go.codegen.endpoints.FnGenerator;
 import software.amazon.smithy.model.Model;
@@ -481,6 +482,15 @@ default void generateEndpointResolutionTests(GenerationContext context) {
         generator.generateTests(context);
     }
 
+    /**
+     * Generates smithy client auth components.
+     *
+     * @param context The generation context.
+     */
+    default void generateAuth(GenerationContext context) {
+        new AuthGenerator(context).generate();
+    }
+
     /**
      * Context object used for service serialization and deserialization.
      */