Generate basic Go module with structures

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

@@ -3,12 +3,8 @@
     "plugins": {
         "go-codegen": {
             "service": "example.weather#Weather",
-            "targetNamespace": "Weather",
-            "package": "weather",
-            "packageVersion": "0.0.1",
-            "packageJson": {
-                "license": "Apache-2.0"
-            }
+            "module": "weather",
+            "moduleVersion": "0.0.1"
         }
     }
 }

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

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2020 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;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.Charset;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+import software.amazon.smithy.codegen.core.CodegenException;
+import software.amazon.smithy.utils.StringUtils;
+
+/**
+ * Utility methods likely to be needed across packages.
+ */
+public final class CodegenUtils {
+
+    private static final Logger LOGGER = Logger.getLogger(CodegenUtils.class.getName());
+
+    private CodegenUtils() {}
+
+    /**
+     * Executes a given shell command in a given directory.
+     *
+     * @param command The string command to execute, e.g. "go fmt".
+     * @param directory The directory to run the command in.
+     * @return Returns the console output of the command.
+     */
+    public static String runCommand(String command, Path directory) {
+        String[] finalizedCommand;
+        if (System.getProperty("os.name").toLowerCase().startsWith("windows")) {
+            finalizedCommand = new String[]{"cmd.exe", "/c", command};
+        } else {
+            finalizedCommand = new String[]{"sh", "-c", command};
+        }
+
+        ProcessBuilder processBuilder = new ProcessBuilder(finalizedCommand)
+                .redirectErrorStream(true)
+                .directory(directory.toFile());
+
+        try {
+            Process process = processBuilder.start();
+            List<String> output = new ArrayList<>();
+
+            // Capture output for reporting.
+            try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(
+                    process.getInputStream(), Charset.defaultCharset()))) {
+                String line;
+                while ((line = bufferedReader.readLine()) != null) {
+                    LOGGER.finest(line);
+                    output.add(line);
+                }
+            }
+
+            process.waitFor();
+            process.destroy();
+
+            String joinedOutput = String.join(System.lineSeparator(), output);
+            if (process.exitValue() != 0) {
+                throw new CodegenException(String.format(
+                        "Command `%s` failed with output:%n%n%s", command, joinedOutput));
+            }
+            return joinedOutput;
+        } catch (InterruptedException | IOException e) {
+            throw new CodegenException(e);
+        }
+    }
+
+    /**
+     * Gets the name under which the given package will be exported by default.
+     *
+     * @param packageName The full package name of the exported package.
+     * @return The name a the package will be imported under by default.
+     */
+    public static String getDefaultPackageImportName(String packageName) {
+        if (StringUtils.isBlank(packageName) || !packageName.contains("/")) {
+            return packageName;
+        }
+        return packageName.substring(packageName.lastIndexOf('/') + 1);
+    }
+}

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

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2020 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;
+
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.logging.Logger;
+import software.amazon.smithy.build.FileManifest;
+import software.amazon.smithy.build.PluginContext;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.neighbor.Walker;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.model.shapes.Shape;
+import software.amazon.smithy.model.shapes.ShapeVisitor;
+import software.amazon.smithy.model.shapes.StructureShape;
+
+/**
+ * Orchestrates Go client generation.
+ */
+final class CodegenVisitor extends ShapeVisitor.Default<Void> {
+
+    private static final Logger LOGGER = Logger.getLogger(CodegenVisitor.class.getName());
+
+    private final GoSettings settings;
+    private final Model model;
+    private final Model modelWithoutTraitShapes;
+    private final ServiceShape service;
+    private final FileManifest fileManifest;
+    private final SymbolProvider symbolProvider;
+    private final GoDelegator writers;
+
+    CodegenVisitor(PluginContext context) {
+        settings = GoSettings.from(context.getSettings());
+        model = context.getModel();
+        modelWithoutTraitShapes = context.getModelWithoutTraitShapes();
+        service = settings.getService(model);
+        fileManifest = context.getFileManifest();
+        LOGGER.info(() -> "Generating Go client for service " + service.getId());
+
+        symbolProvider = GoCodegenPlugin.createSymbolProvider(model);
+        writers = new GoDelegator(settings, model, fileManifest, symbolProvider);
+    }
+
+    void execute() {
+        // Generate models that are connected to the service being generated.
+        LOGGER.fine("Walking shapes from " + service.getId() + " to find shapes to generate");
+        Set<Shape> serviceShapes = new TreeSet<>(new Walker(modelWithoutTraitShapes).walkShapes(service));
+
+        for (Shape shape : serviceShapes) {
+            shape.accept(this);
+        }
+
+        LOGGER.fine("Flushing go writers");
+        writers.flushWriters();
+
+        LOGGER.fine("Generating go.mod file");
+        GoModGenerator.writeGoMod(settings, fileManifest);
+
+        LOGGER.fine("Running go fmt");
+        CodegenUtils.runCommand("go fmt", fileManifest.getBaseDir());
+    }
+
+    @Override
+    protected Void getDefault(Shape shape) {
+        return null;
+    }
+
+    @Override
+    public Void structureShape(StructureShape shape) {
+        writers.useShapeWriter(shape, writer -> new StructureGenerator(model, symbolProvider, writer, shape).run());
+        return null;
+    }
+}

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

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 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;
+
+import software.amazon.smithy.build.PluginContext;
+import software.amazon.smithy.build.SmithyBuildPlugin;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.model.Model;
+
+/**
+ * Plugin to trigger Go code generation.
+ */
+public final class GoCodegenPlugin implements SmithyBuildPlugin {
+    @Override
+    public String getName() {
+        return "go-codegen";
+    }
+
+    @Override
+    public void execute(PluginContext context) {
+        new CodegenVisitor(context).execute();
+    }
+
+    /**
+     * Creates a Go symbol provider.
+     * @param model The model to generate symbols for.
+     * @return Returns the created provider.
+     */
+    public static SymbolProvider createSymbolProvider(Model model) {
+        return new SymbolVisitor(model);
+    }
+}

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

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2020 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;
+
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Consumer;
+import software.amazon.smithy.build.FileManifest;
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.shapes.Shape;
+
+/**
+ * Manages writers for Go files.
+ */
+final class GoDelegator {
+
+    private final GoSettings settings;
+    private final Model model;
+    private final FileManifest fileManifest;
+    private final SymbolProvider symbolProvider;
+    private final Map<String, GoWriter> writers = new HashMap<>();
+
+    GoDelegator(GoSettings settings, Model model, FileManifest fileManifest, SymbolProvider symbolProvider) {
+        this.settings = settings;
+        this.model = model;
+        this.fileManifest = fileManifest;
+        this.symbolProvider = symbolProvider;
+    }
+
+    /**
+     * Writes all pending writers to disk and then clears them out.
+     */
+    void flushWriters() {
+        writers.forEach((filename, writer) -> fileManifest.writeFile(filename, writer.toString()));
+        writers.clear();
+    }
+
+    /**
+     * Gets a previously created writer or creates a new one if needed.
+     *
+     * @param shape Shape to create the writer for.
+     * @param writerConsumer Consumer that accepts and works with the file.
+     */
+    void useShapeWriter(Shape shape, Consumer<GoWriter> writerConsumer) {
+        Symbol symbol = symbolProvider.toSymbol(shape);
+        String namespace = symbol.getNamespace();
+        if (namespace.equals(".")) {
+            namespace = CodegenUtils.getDefaultPackageImportName(settings.getModuleName());
+        }
+        GoWriter writer = checkoutWriter(symbol.getDefinitionFile(), namespace);
+
+        writer.pushState();
+        writerConsumer.accept(writer);
+        writer.popState();
+    }
+
+    private GoWriter checkoutWriter(String filename, String namespace) {
+        String formattedFilename = Paths.get(filename).normalize().toString();
+        boolean needsNewline = writers.containsKey(formattedFilename);
+
+        GoWriter writer = writers.computeIfAbsent(formattedFilename, f -> new GoWriter(namespace));
+
+        if (needsNewline) {
+            writer.write("\n");
+        }
+
+        return writer;
+    }
+}

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

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 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;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import software.amazon.smithy.build.FileManifest;
+import software.amazon.smithy.codegen.core.CodegenException;
+
+/**
+ * Generates a go.mod file for the project.
+ *
+ * <p>See here for more information on the format: https://github.com/golang/go/wiki/Modules#gomod
+ *
+ * TODO: pull in dependencies
+ */
+final class GoModGenerator {
+
+    private GoModGenerator() {}
+
+    static void writeGoMod(GoSettings settings, FileManifest manifest) {
+        Path goModFile = manifest.getBaseDir().resolve("go.mod");
+
+        // `go mod init` will fail if the `go.mod` already exists, so this deletes
+        //  it if it's present in the output. While it's technically possible
+        //  to simply edit the file, it's easier to just start fresh.
+        if (Files.exists(goModFile)) {
+            try {
+                Files.delete(goModFile);
+            } catch (IOException e) {
+                throw new CodegenException("Failed to delete existing go.mod file", e);
+            }
+        }
+        CodegenUtils.runCommand("go mod init " + settings.getModuleName(), manifest.getBaseDir());
+    }
+}