Add new service builder codegen (#1693)

* Add `ServerProtocol` interface to allow for server side protocol specific methods.

* Make public the structs merged in #1679.

* Add `ServerOperationGenerator`, which generates a ZST and implements `OperationShape` on it.

* Add `ServerServiceGeneratorV2`, which generates the service newtype around a router and a service builder.

* Add `hidden` argument to `RustModule` which allows modules to be marked with `#[doc(hidden)]`.

* Add `BuildModifier` trait to provide a common interface for extending service builders.

* Add `Upgradable` trait to simplifying bounds when upgrading from an `Operation` to a HTTP service.

* Add `FromRequest`, `FromParts`, and `IntoResponse` implementations.

* Make `RoutingService` accept general body types `B` for the inner services `http::Response<B>`.

* Use new service builder in protocol tests.

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/rustlang/Writable.kt

@@ -26,6 +26,13 @@ fun Writable.isEmpty(): Boolean {
     return writer.toString() == RustWriter.root().toString()
 }
 
+operator fun Writable.plus(other: Writable): Writable {
+    val first = this
+    return writable {
+        rustTemplate("#{First:W}#{Second:W}", "First" to first, "Second" to other)
+    }
+}
+
 /**
  * Helper allowing a `Iterable<Writable>` to be joined together using a `String` separator.
  */

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/protocols/AwsJson.kt

@@ -129,7 +129,7 @@ class AwsJsonSerializerGenerator(
 }
 
 open class AwsJson(
-    private val coreCodegenContext: CoreCodegenContext,
+    val coreCodegenContext: CoreCodegenContext,
     private val awsJsonVersion: AwsJsonVersion,
 ) : Protocol {
     private val runtimeConfig = coreCodegenContext.runtimeConfig
@@ -143,6 +143,8 @@ open class AwsJson(
     )
     private val jsonDeserModule = RustModule.private("json_deser")
 
+    val version: AwsJsonVersion get() = awsJsonVersion
+
     override val httpBindingResolver: HttpBindingResolver =
         AwsJsonHttpBindingResolver(coreCodegenContext.model, awsJsonVersion)
 

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/protocols/RestJson.kt

@@ -87,7 +87,7 @@ class RestJsonHttpBindingResolver(
     }
 }
 
-class RestJson(private val coreCodegenContext: CoreCodegenContext) : Protocol {
+open class RestJson(val coreCodegenContext: CoreCodegenContext) : Protocol {
     private val runtimeConfig = coreCodegenContext.runtimeConfig
     private val errorScope = arrayOf(
         "Bytes" to RuntimeType.Bytes,

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/protocols/RestXml.kt

@@ -53,7 +53,7 @@ class RestXmlFactory(
     }
 }
 
-open class RestXml(private val coreCodegenContext: CoreCodegenContext) : Protocol {
+open class RestXml(val coreCodegenContext: CoreCodegenContext) : Protocol {
     private val restXml = coreCodegenContext.serviceShape.expectTrait<RestXmlTrait>()
     private val runtimeConfig = coreCodegenContext.runtimeConfig
     private val errorScope = arrayOf(

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/ServerRuntimeType.kt

@@ -39,6 +39,8 @@ object ServerRuntimeType {
     fun ResponseRejection(runtimeConfig: RuntimeConfig) =
         RuntimeType("ResponseRejection", ServerCargoDependency.SmithyHttpServer(runtimeConfig), "${runtimeConfig.crateSrcPrefix}_http_server::rejection")
 
-    fun Protocol(runtimeConfig: RuntimeConfig) =
-        RuntimeType("Protocol", ServerCargoDependency.SmithyHttpServer(runtimeConfig), "${runtimeConfig.crateSrcPrefix}_http_server::protocols")
+    fun Protocol(name: String, runtimeConfig: RuntimeConfig) =
+        RuntimeType(name, ServerCargoDependency.SmithyHttpServer(runtimeConfig), "${runtimeConfig.crateSrcPrefix}_http_server::protocols")
+
+    fun Protocol(runtimeConfig: RuntimeConfig) = Protocol("Protocol", runtimeConfig)
 }

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/generators/ServerOperationGenerator.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.rust.codegen.server.smithy.generators
+
+import software.amazon.smithy.model.shapes.OperationShape
+import software.amazon.smithy.rust.codegen.client.rustlang.RustWriter
+import software.amazon.smithy.rust.codegen.client.rustlang.Writable
+import software.amazon.smithy.rust.codegen.client.rustlang.asType
+import software.amazon.smithy.rust.codegen.client.rustlang.documentShape
+import software.amazon.smithy.rust.codegen.client.rustlang.rust
+import software.amazon.smithy.rust.codegen.client.rustlang.rustTemplate
+import software.amazon.smithy.rust.codegen.client.rustlang.writable
+import software.amazon.smithy.rust.codegen.client.smithy.CoreCodegenContext
+import software.amazon.smithy.rust.codegen.client.util.toPascalCase
+import software.amazon.smithy.rust.codegen.server.smithy.ServerCargoDependency
+
+class ServerOperationGenerator(
+    coreCodegenContext: CoreCodegenContext,
+    private val operation: OperationShape,
+) {
+    private val runtimeConfig = coreCodegenContext.runtimeConfig
+    private val codegenScope =
+        arrayOf(
+            "SmithyHttpServer" to
+                ServerCargoDependency.SmithyHttpServer(runtimeConfig).asType(),
+        )
+    private val symbolProvider = coreCodegenContext.symbolProvider
+    private val model = coreCodegenContext.model
+
+    private val operationName = symbolProvider.toSymbol(operation).name.toPascalCase()
+    private val operationId = operation.id
+
+    /** Returns `std::convert::Infallible` if the model provides no errors. */
+    private fun operationError(): Writable = writable {
+        if (operation.errors.isEmpty()) {
+            rust("std::convert::Infallible")
+        } else {
+            rust("crate::error::${operationName}Error")
+        }
+    }
+
+    fun render(writer: RustWriter) {
+        writer.documentShape(operation, model)
+
+        writer.rustTemplate(
+            """
+            pub struct $operationName;
+
+            impl #{SmithyHttpServer}::operation::OperationShape for $operationName {
+                const NAME: &'static str = "${operationId.toString().replace("#", "##")}";
+
+                type Input = crate::input::${operationName}Input;
+                type Output = crate::output::${operationName}Output;
+                type Error = #{Error:W};
+            }
+            """,
+            "Error" to operationError(),
+            *codegenScope,
+        )
+        // Adds newline to end of render
+        writer.rust("")
+    }
+}

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/generators/ServerServiceGenerator.kt

@@ -7,14 +7,18 @@ package software.amazon.smithy.rust.codegen.server.smithy.generators
 
 import software.amazon.smithy.model.knowledge.TopDownIndex
 import software.amazon.smithy.model.shapes.OperationShape
+import software.amazon.smithy.rust.codegen.client.rustlang.Attribute
+import software.amazon.smithy.rust.codegen.client.rustlang.RustMetadata
 import software.amazon.smithy.rust.codegen.client.rustlang.RustModule
 import software.amazon.smithy.rust.codegen.client.rustlang.RustWriter
+import software.amazon.smithy.rust.codegen.client.rustlang.Visibility
 import software.amazon.smithy.rust.codegen.client.smithy.CoreCodegenContext
 import software.amazon.smithy.rust.codegen.client.smithy.DefaultPublicModules
 import software.amazon.smithy.rust.codegen.client.smithy.RustCrate
 import software.amazon.smithy.rust.codegen.client.smithy.generators.protocol.ProtocolGenerator
 import software.amazon.smithy.rust.codegen.client.smithy.generators.protocol.ProtocolSupport
 import software.amazon.smithy.rust.codegen.client.smithy.protocols.Protocol
+import software.amazon.smithy.rust.codegen.server.smithy.generators.protocol.ServerProtocol
 import software.amazon.smithy.rust.codegen.server.smithy.generators.protocol.ServerProtocolTestGenerator
 
 /**
@@ -63,6 +67,36 @@ open class ServerServiceGenerator(
         ) { writer ->
             renderOperationRegistry(writer, operations)
         }
+
+        // TODO(https://github.com/awslabs/smithy-rs/issues/1707): Remove, this is temporary.
+        rustCrate.withModule(
+            RustModule(
+                "operation_shape",
+                RustMetadata(
+                    visibility = Visibility.PUBLIC,
+                    additionalAttributes = listOf(
+                        Attribute.DocHidden,
+                    ),
+                ),
+                null,
+            ),
+        ) { writer ->
+            for (operation in operations) {
+                ServerOperationGenerator(coreCodegenContext, operation).render(writer)
+            }
+        }
+
+        // TODO(https://github.com/awslabs/smithy-rs/issues/1707): Remove, this is temporary.
+        rustCrate.withModule(
+            RustModule("service", RustMetadata(visibility = Visibility.PUBLIC, additionalAttributes = listOf(Attribute.DocHidden)), null),
+        ) { writer ->
+            val serverProtocol = ServerProtocol.fromCoreProtocol(protocol)
+            ServerServiceGeneratorV2(
+                coreCodegenContext,
+                serverProtocol,
+            ).render(writer)
+        }
+
         renderExtras(operations)
     }