Enable shapes-only codegen

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 +145,153 @@ 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`.
+
+Unlike when generating a client, a service shape is not required for shape
+generation. If a service is not provided then every shape found in the model
+will be generated. Any naming conflicts may be resolved by using the
+[`renameShapes` transform](https://smithy.io/2.0/guides/smithy-build-json.html#renameshapes)
+(or renaming the shapes in the model of course).
+
+The set of shapes generated can also be constrained by using the
+[`includeShapesBySelector` transform](https://smithy.io/2.0/guides/smithy-build-json.html#includeshapesbyselector).
+For example, to generate only shapes within the `com.example` namespace:
+
+```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": {
+            "transforms": [
+                {
+                    "name": "includeShapesBySelector",
+                    "args": {
+                        "selector": "[id|namespace = 'com.example']"
+                    }
+                }
+            ],
+            "plugins": {
+                "python-shape-codegen": {
+                    "module": "echo",
+                    "moduleVersion": "0.0.1"
+                }
+            }
+        }
+    }
+}
+```
+
+Input and output shapes (shapes with the `@input` or `@output` traits and
+operation inputs / outputs created as part of an operation definition) are not
+generated by default. To generate these shapes anyway, remove the traits with
+the
+[`excludeTraits` transform](https://smithy.io/2.0/guides/smithy-build-json.html#excludetraits):
+
+```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": {
+            "transforms": [
+                {
+                    "name": "excludeTraits",
+                    "args": {
+                        "traits": ["input", "output"]
+                    }
+                }
+            ],
+            "plugins": {
+                "python-shape-codegen": {
+                    "module": "echo",
+                    "moduleVersion": "0.0.1"
+                }
+            }
+        }
+    }
+}
+```
+
+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

@@ -50,6 +50,8 @@
 import software.amazon.smithy.model.shapes.ServiceShape;
 import software.amazon.smithy.model.shapes.Shape;
 import software.amazon.smithy.model.shapes.ShapeId;
+import software.amazon.smithy.model.traits.InputTrait;
+import software.amazon.smithy.model.traits.OutputTrait;
 import software.amazon.smithy.python.codegen.generators.ListGenerator;
 import software.amazon.smithy.python.codegen.generators.MapGenerator;
 import software.amazon.smithy.python.codegen.integration.ProtocolGenerator;
@@ -112,10 +114,13 @@ 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 (directive.settings().artifactType().equals(PythonSettings.ArtifactType.SHAPES)) {
+            return;
+        }
+
+        new ConfigGenerator(directive.settings(), directive.context()).run();
         var serviceIndex = ServiceIndex.of(directive.model());
         if (directive.context().applicationProtocol().isHttpProtocol()
                 && !serviceIndex.getAuthSchemes(directive.service()).isEmpty()) {
@@ -130,12 +135,18 @@ private void generateSchemas(GenerationContext context, Collection<Shape> shapes
                 .filter(shapes::contains)
                 .filter(shape -> !shape.isOperationShape() && !shape.isResourceShape()
                         && !shape.isServiceShape() && !shape.isMemberShape() && !Prelude.isPreludeShape(shape))
+                // If we're only generating data shapes, there's no need to generate input or output shapes.
+                .filter(shape -> shape.isStructureShape() && !shouldGenerateStructure(context.settings(), shape))
                 .forEach(schemaGenerator);
         schemaGenerator.finalizeRecursiveShapes();
     }
 
     @Override
     public void generateService(GenerateServiceDirective<GenerationContext, PythonSettings> directive) {
+        if (directive.settings().artifactType().equals(PythonSettings.ArtifactType.SHAPES)) {
+            return;
+        }
+
         new ClientGenerator(directive.context(), directive.service()).run();
 
         var protocolGenerator = directive.context().protocolGenerator();
@@ -197,6 +208,11 @@ public void generateResource(GenerateResourceDirective<GenerationContext, Python
 
     @Override
     public void generateStructure(GenerateStructureDirective<GenerationContext, PythonSettings> directive) {
+        // If we're only generating data shapes, there's no need to generate input or output shapes.
+        if (!shouldGenerateStructure(directive.settings(), directive.shape())) {
+            return;
+        }
+
         directive.context().writerDelegator().useShapeWriter(directive.shape(), writer -> {
             StructureGenerator generator = new StructureGenerator(
                     directive.context(),
@@ -208,6 +224,14 @@ public void generateStructure(GenerateStructureDirective<GenerationContext, Pyth
         });
     }
 
+    private boolean shouldGenerateStructure(PythonSettings settings, Shape shape) {
+        if (shape.getId().getNamespace().equals("smithy.synthetic")) {
+            return false;
+        }
+        return !(settings.artifactType().equals(PythonSettings.ArtifactType.SHAPES)
+                && (shape.hasTrait(InputTrait.class) || shape.hasTrait(OutputTrait.class)));
+    }
+
     @Override
     public void generateError(GenerateErrorDirective<GenerationContext, PythonSettings> directive) {
         directive.context().writerDelegator().useShapeWriter(directive.shape(), writer -> {

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

@@ -16,6 +16,7 @@
 package software.amazon.smithy.python.codegen;
 
 import java.util.Arrays;
+import java.util.Locale;
 import java.util.Objects;
 import software.amazon.smithy.codegen.core.CodegenException;
 import software.amazon.smithy.model.Model;
@@ -35,13 +36,15 @@
  * @param moduleName The name of the module to generate.
  * @param moduleVersion The version of the module to generate.
  * @param moduleDescription The optional module description for the module that will be generated.
+ * @param artifactType The type of artifact being generated (e.g. client/shapes/server)
  */
 @SmithyUnstableApi
 public record PythonSettings(
         ShapeId service,
         String moduleName,
         String moduleVersion,
-        String moduleDescription
+        String moduleDescription,
+        ArtifactType artifactType
     ) implements ToSmithyBuilder<PythonSettings> {
 
     private static final String SERVICE = "service";
@@ -60,14 +63,15 @@ public record PythonSettings(
         }
     }
 
-    public PythonSettings(Builder builder) {
+    private PythonSettings(Builder builder) {
         this(
                 builder.service,
                 builder.moduleName,
                 builder.moduleVersion,
                 StringUtils.isBlank(builder.moduleDescription)
-                        ? builder.moduleName + " client"
-                        : builder.moduleDescription
+                        ? builder.moduleName + " " + builder.artifactType.name().toLowerCase(Locale.ENGLISH)
+                        : builder.moduleDescription,
+                builder.artifactType
         );
     }
 
@@ -105,13 +109,22 @@ public static PythonSettings fromNode(ObjectNode config) {
         return builder.build();
     }
 
+    /**
+     * The type of artifact being generated.
+     */
+    public enum ArtifactType {
+        CLIENT,
+        SHAPES;
+    }
+
     @Override
-    public SmithyBuilder<PythonSettings> toBuilder() {
+    public Builder toBuilder() {
         return builder()
                 .service(service)
                 .moduleName(moduleName)
                 .moduleVersion(moduleVersion)
-                .moduleDescription(moduleDescription);
+                .moduleDescription(moduleDescription)
+                .artifactType(artifactType);
     }
 
     public static Builder builder() {
@@ -124,6 +137,7 @@ public static class Builder implements SmithyBuilder<PythonSettings> {
         private String moduleName;
         private String moduleVersion;
         private String moduleDescription;
+        private ArtifactType artifactType = ArtifactType.CLIENT;
 
         @Override
         public PythonSettings build() {
@@ -152,5 +166,10 @@ public Builder moduleDescription(String moduleDescription) {
             this.moduleDescription = moduleDescription;
             return this;
         }
+
+        public Builder artifactType(ArtifactType artifactType) {
+            this.artifactType = artifactType;
+            return this;
+        }
     }
 }