Enable shapes-only codegen

This adds an alternative generation mode that only generates "data
shapes".

Author: JordonPhillips

README.md

@@ -28,7 +28,7 @@ This repository does *not* contain any generated clients, such as for S3 or othe
 AWS services. Rather, these are the tools that facilitate the generation of those
 clients and non-AWS Smithy clients.
 
-### How do I use this?
+### How do I use this to create a client?
 
 The first step is to create a Smithy pacakge. If this is your first time working
 with Smithy, follow [this quickstart guide](https://smithy.io/2.0/quickstart.html)
@@ -82,8 +82,8 @@ this file, see the
     "sources": ["model"],
     "maven": {
         "dependencies": [
-            "software.amazon.smithy:smithy-model:[1.34.0,2.0)",
-            "software.amazon.smithy:smithy-aws-traits:[1.34.0,2.0)",
+            "software.amazon.smithy:smithy-model:[1.54.0,2.0)",
+            "software.amazon.smithy:smithy-aws-traits:[1.54.0,2.0)",
             "software.amazon.smithy.python:smithy-python-codegen:0.1.0"
         ]
     },
@@ -145,6 +145,107 @@ Only for now. Once the generator has been published, the Smithy CLI will be able
 to run it without a separate Java installation. Similarly, once the python
 helper libraries have been published you won't need to install them manually.
 
+### How do I generate types for shapes without a client?
+
+If all you want are concrete Python classes for the shapes in your Smithy model,
+all you need to do is replace `python-client-codegen` with
+`python-shape-codegen` when following the steps above. Your `smithy-build.json`
+would now look like:
+
+```json
+{
+    "version": "1.0",
+    "sources": ["model"],
+    "maven": {
+        "dependencies": [
+            "software.amazon.smithy:smithy-model:[1.54.0,2.0)",
+            "software.amazon.smithy.python:smithy-python-codegen:0.1.0"
+        ]
+    },
+    "projections": {
+        "shapes": {
+            "plugins": {
+                "python-shape-codegen": {
+                    "service": "com.example#EchoService",
+                    "module": "echo",
+                    "moduleVersion": "0.0.1"
+                }
+            }
+        }
+    }
+}
+```
+
+The module with the generated shape classes can be found in
+`build/smithy/client/python-shape-codegen` after you run `smithy-build`.
+
+Note that a service shape is still required. In this case, it's used for the
+purposes of namespacing since all shapes within a service's closure must have a
+unique name. The service shape also has the `rename` property to resolve any
+conflicts you might encounter.
+
+The one downside to this is that at time of writing there is no way to add
+shapes to a service that aren't connected to it via an operation or error. In
+the future, the service shape will have a `shapes` property or some other way of
+doing this. For now, it is recommended to just create a dummy operation to add
+any shapes needed, like below:
+
+```smithy
+$version: "2.0"
+
+namespace com.example
+
+service ShapeNamespaceService {
+    version: "2006-03-01"
+    operations: [ShapeContainer]
+}
+
+operation ShapeContainer {
+    input := {
+        example: ExampleShape
+    }
+}
+
+structure ExampleShape {
+    intMember: Integer
+}
+```
+
+You can also generate both a client package and a shape package in one build,
+but they won't depend on each other. To do this, just add both plugins in the
+projection, or create a projection for each plugin. Below is an example showing
+both plugins in one projection:
+
+```json
+{
+    "version": "1.0",
+    "sources": ["model"],
+    "maven": {
+        "dependencies": [
+            "software.amazon.smithy:smithy-model:[1.54.0,2.0)",
+            "software.amazon.smithy:smithy-aws-traits:[1.54.0,2.0)",
+            "software.amazon.smithy.python:smithy-python-codegen:0.1.0"
+        ]
+    },
+    "projections": {
+        "client": {
+            "plugins": {
+                "python-client-codegen": {
+                    "service": "com.example#EchoService",
+                    "module": "echo",
+                    "moduleVersion": "0.0.1"
+                },
+                "python-shape-codegen": {
+                    "service": "com.example#EchoService",
+                    "module": "echo",
+                    "moduleVersion": "0.0.1"
+                }
+            }
+        }
+    }
+}
+```
+
 ### Core Modules and Interfaces
 
 * `smithy-core` provides transport-agnostic core modules and interfaces

codegen/smithy-python-codegen-test/smithy-build.json

@@ -5,6 +5,11 @@
             "service": "example.weather#Weather",
             "module": "weather",
             "moduleVersion": "0.0.1"
+        },
+        "python-shape-codegen": {
+            "service": "example.weather#Weather",
+            "module": "weather",
+            "moduleVersion": "0.0.1"
         }
     }
 }

codegen/smithy-python-codegen/src/main/java/software/amazon/smithy/python/codegen/DirectedPythonCodegen.java

@@ -62,6 +62,16 @@ final class DirectedPythonCodegen implements DirectedCodegen<GenerationContext,
     private static final Logger LOGGER = Logger.getLogger(DirectedPythonCodegen.class.getName());
     private static final int PYTHON_MINOR_VERSION = 12; // 3.12
 
+    private final boolean shapesOnly;
+
+    DirectedPythonCodegen(boolean shapesOnly) {
+        this.shapesOnly = shapesOnly;
+    }
+
+    DirectedPythonCodegen() {
+        this(false);
+    }
+
     @Override
     public SymbolProvider createSymbolProvider(CreateSymbolProviderDirective<PythonSettings> directive) {
         return new SymbolVisitor(directive.model(), directive.settings());
@@ -112,10 +122,13 @@ private ProtocolGenerator resolveProtocolGenerator(
     @Override
     public void customizeBeforeShapeGeneration(CustomizeDirective<GenerationContext, PythonSettings> directive) {
         generateServiceErrors(directive.settings(), directive.context().writerDelegator());
-        new ConfigGenerator(directive.settings(), directive.context()).run();
-
         generateSchemas(directive.context(), directive.connectedShapes().values());
 
+        if (shapesOnly) {
+            return;
+        }
+
+        new ConfigGenerator(directive.settings(), directive.context()).run();
         var serviceIndex = ServiceIndex.of(directive.model());
         if (directive.context().applicationProtocol().isHttpProtocol()
                 && !serviceIndex.getAuthSchemes(directive.service()).isEmpty()) {
@@ -136,6 +149,10 @@ private void generateSchemas(GenerationContext context, Collection<Shape> shapes
 
     @Override
     public void generateService(GenerateServiceDirective<GenerationContext, PythonSettings> directive) {
+        if (shapesOnly) {
+            return;
+        }
+
         new ClientGenerator(directive.context(), directive.service()).run();
 
         var protocolGenerator = directive.context().protocolGenerator();

codegen/smithy-python-codegen/src/main/java/software/amazon/smithy/python/codegen/PythonSettings.java

@@ -41,7 +41,8 @@ public record PythonSettings(
         ShapeId service,
         String moduleName,
         String moduleVersion,
-        String moduleDescription
+        String moduleDescription,
+        boolean shapesOnly
     ) implements ToSmithyBuilder<PythonSettings> {
 
     private static final String SERVICE = "service";
@@ -67,7 +68,8 @@ public PythonSettings(Builder builder) {
                 builder.moduleVersion,
                 StringUtils.isBlank(builder.moduleDescription)
                         ? builder.moduleName + " client"
-                        : builder.moduleDescription
+                        : builder.moduleDescription,
+                builder.shapesOnly
         );
     }
 
@@ -106,12 +108,13 @@ public static PythonSettings fromNode(ObjectNode config) {
     }
 
     @Override
-    public SmithyBuilder<PythonSettings> toBuilder() {
+    public Builder toBuilder() {
         return builder()
                 .service(service)
                 .moduleName(moduleName)
                 .moduleVersion(moduleVersion)
-                .moduleDescription(moduleDescription);
+                .moduleDescription(moduleDescription)
+                .shapesOnly(shapesOnly);
     }
 
     public static Builder builder() {
@@ -124,6 +127,7 @@ public static class Builder implements SmithyBuilder<PythonSettings> {
         private String moduleName;
         private String moduleVersion;
         private String moduleDescription;
+        private boolean shapesOnly = false;
 
         @Override
         public PythonSettings build() {
@@ -152,5 +156,10 @@ public Builder moduleDescription(String moduleDescription) {
             this.moduleDescription = moduleDescription;
             return this;
         }
+
+        public Builder shapesOnly(boolean shapesOnly) {
+            this.shapesOnly = shapesOnly;
+            return this;
+        }
     }
 }

codegen/smithy-python-codegen/src/main/java/software/amazon/smithy/python/codegen/PythonShapeCodegenPlugin.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.python.codegen;
+
+import software.amazon.smithy.build.PluginContext;
+import software.amazon.smithy.build.SmithyBuildPlugin;
+import software.amazon.smithy.codegen.core.directed.CodegenDirector;
+import software.amazon.smithy.python.codegen.integration.PythonIntegration;
+
+public final class PythonShapeCodegenPlugin implements SmithyBuildPlugin {
+    @Override
+    public String getName() {
+        return "python-shape-codegen";
+    }
+
+    @Override
+    public void execute(PluginContext context) {
+        CodegenDirector<PythonWriter, PythonIntegration, GenerationContext, PythonSettings> runner
+                = new CodegenDirector<>();
+
+        PythonSettings settings = PythonSettings.fromNode(context.getSettings()).toBuilder()
+                .shapesOnly(true)
+                .build();
+        runner.settings(settings);
+        runner.directedCodegen(new DirectedPythonCodegen(true));
+        runner.fileManifest(context.getFileManifest());
+        runner.service(settings.service());
+        runner.model(context.getModel());
+        runner.integrationClass(PythonIntegration.class);
+        runner.performDefaultCodegenTransforms();
+        runner.run();
+    }
+}

codegen/smithy-python-codegen/src/main/java/software/amazon/smithy/python/codegen/integration/HttpApiKeyAuth.java

@@ -57,7 +57,7 @@ public List<RuntimeClientPlugin> getClientPlugins() {
 
     @Override
     public void customize(GenerationContext context) {
-        if (!hasApiKeyAuth(context)) {
+        if (!hasApiKeyAuth(context) || context.settings().shapesOnly()) {
             return;
         }
         var trait = context.settings().service(context.model()).expectTrait(HttpApiKeyAuthTrait.class);

codegen/smithy-python-codegen/src/main/resources/META-INF/services/software.amazon.smithy.build.SmithyBuildPlugin

@@ -4,3 +4,4 @@
 #
 
 software.amazon.smithy.python.codegen.PythonClientCodegenPlugin
+software.amazon.smithy.python.codegen.PythonShapeCodegenPlugin