Support a single protocol in the generator

This commit updates the generator to support a single protocol and
removes the protocol name from the runtime code. We can add support for
multiple protocols in the future if needed (for example, if a service
actually splits their operations across protocols), but for now, it's
safer to expose only a single protocol in both the generator and the
generated code. The location and format of the generated protocol code
all remains the same, however, the generator no longer supports multiple
protocols in the "protocols" option, there's no longer a code generated
"protocol" property available at runtime, and the method that used to
dispatch to different protocols now just supports calling a single
protocol.

Author: mtdowling

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/ApplicationProtocol.java

@@ -15,25 +15,16 @@
 
 package software.amazon.smithy.typescript.codegen;
 
-import java.util.Collection;
-import java.util.List;
 import java.util.Objects;
-import java.util.logging.Logger;
-import java.util.stream.Collectors;
 import software.amazon.smithy.codegen.core.Symbol;
 import software.amazon.smithy.codegen.core.SymbolReference;
-import software.amazon.smithy.model.shapes.ServiceShape;
-import software.amazon.smithy.typescript.codegen.integration.ProtocolGenerator;
-import software.amazon.smithy.typescript.codegen.integration.TypeScriptIntegration;
 
 /**
  * Represents the resolves {@link Symbol}s and references for an
  * application protocol (e.g., "http", "mqtt", etc).
  */
 public final class ApplicationProtocol {
 
-    private static final Logger LOGGER = Logger.getLogger(ApplicationProtocol.class.getName());
-
     private final String name;
     private final SymbolReference optionsType;
     private final SymbolReference requestType;
@@ -92,36 +83,6 @@ private static Symbol createHttpSymbol(TypeScriptDependency dependency, String s
                 .build();
     }
 
-    static ApplicationProtocol resolve(
-            TypeScriptSettings settings,
-            ServiceShape service,
-            Collection<TypeScriptIntegration> integrations
-    ) {
-        List<String> resolvedProtocols = settings.resolveServiceProtocols(service);
-        // Get the list of protocol generators that have implementations from the service.
-        List<ProtocolGenerator> generators = integrations.stream()
-                .flatMap(integration -> integration.getProtocolGenerators().stream())
-                .filter(generator -> resolvedProtocols.contains(generator.getName()))
-                .collect(Collectors.toList());
-
-        if (generators.isEmpty()) {
-            // Default to "http" if no protocols are configured.
-            LOGGER.warning(String.format(
-                    "No protocol generators could be found for the protocols supported by this service "
-                    + "`%s`: %s. Assuming an HTTP-based protocol.", service.getId(), resolvedProtocols));
-            return createDefaultHttpApplicationProtocol();
-        }
-
-        // Ensure each protocol is compatible. If not, then an explicit list must be provided.
-        ApplicationProtocol applicationProtocol = generators.get(0).getApplicationProtocol();
-        for (int i = 1; i < generators.size(); i++) {
-            ProtocolGenerator generator = generators.get(i);
-            applicationProtocol = generator.resolveApplicationProtocol(service, generators, applicationProtocol);
-        }
-
-        return applicationProtocol;
-    }
-
     /**
      * Gets the protocol name.
      *

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

@@ -16,16 +16,15 @@
 package software.amazon.smithy.typescript.codegen;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.Optional;
 import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.TreeSet;
-import java.util.function.Function;
 import java.util.logging.Logger;
-import java.util.stream.Collectors;
 import software.amazon.smithy.build.FileManifest;
 import software.amazon.smithy.build.PluginContext;
 import software.amazon.smithy.codegen.core.Symbol;
@@ -43,7 +42,6 @@
 import software.amazon.smithy.model.shapes.StructureShape;
 import software.amazon.smithy.model.shapes.UnionShape;
 import software.amazon.smithy.model.traits.EnumTrait;
-import software.amazon.smithy.model.traits.ProtocolsTrait;
 import software.amazon.smithy.typescript.codegen.integration.ProtocolGenerator;
 import software.amazon.smithy.typescript.codegen.integration.RuntimeClientPlugin;
 import software.amazon.smithy.typescript.codegen.integration.TypeScriptIntegration;
@@ -70,6 +68,7 @@ class CodegenVisitor extends ShapeVisitor.Default<Void> {
     private final TypeScriptDelegator writers;
     private final List<TypeScriptIntegration> integrations = new ArrayList<>();
     private final List<RuntimeClientPlugin> runtimePlugins = new ArrayList<>();
+    private final ProtocolGenerator protocolGenerator;
     private final ApplicationProtocol applicationProtocol;
 
     CodegenVisitor(PluginContext context) {
@@ -100,8 +99,37 @@ class CodegenVisitor extends ShapeVisitor.Default<Void> {
         }
         symbolProvider = SymbolProvider.cache(resolvedProvider);
 
+        // Resolve the nullable protocol generator and application protocol.
+        protocolGenerator = resolveProtocolGenerator(integrations, service, settings);
+        applicationProtocol = protocolGenerator == null
+                ? ApplicationProtocol.createDefaultHttpApplicationProtocol()
+                : protocolGenerator.getApplicationProtocol();
+
         writers = new TypeScriptDelegator(settings, model, fileManifest, symbolProvider, integrations);
-        applicationProtocol = ApplicationProtocol.resolve(settings, service, integrations);
+    }
+
+    private static ProtocolGenerator resolveProtocolGenerator(
+            Collection<TypeScriptIntegration> integrations,
+            ServiceShape service,
+            TypeScriptSettings settings
+    ) {
+        // Collect all of the supported protocol generators.
+        Map<String, ProtocolGenerator> generators = new HashMap<>();
+        for (TypeScriptIntegration integration : integrations) {
+            for (ProtocolGenerator generator : integration.getProtocolGenerators()) {
+                generators.put(generator.getName(), generator);
+            }
+        }
+
+        String protocolName;
+        try {
+            protocolName = settings.resolveServiceProtocol(service, generators.keySet());
+        } catch (UnresolvableProtocolException e) {
+            LOGGER.warning("Unable to find a protocol generator for " + service.getId() + ": " + e.getMessage());
+            protocolName = null;
+        }
+
+        return protocolName != null ? generators.get(protocolName) : null;
     }
 
     void execute() {
@@ -119,12 +147,8 @@ void execute() {
         // Generate the client Node and Browser configuration files. These
         // files are switched between in package.json based on the targeted
         // environment.
-        String defaultProtocolName = getDefaultGenerator().map(ProtocolGenerator::getName).orElse(null);
-        LOGGER.fine("Resolved the default protocol of the client to " + defaultProtocolName);
-
-        // Generate each runtime config file for targeted platforms.
         RuntimeConfigGenerator configGenerator = new RuntimeConfigGenerator(
-                settings, model, symbolProvider, defaultProtocolName, writers, integrations);
+                settings, model, symbolProvider, writers, integrations);
         for (LanguageTarget target : LanguageTarget.values()) {
             LOGGER.fine("Generating " + target + " runtime configuration");
             configGenerator.generate(target);
@@ -151,19 +175,6 @@ void execute() {
                 settings, fileManifest, SymbolDependency.gatherDependencies(dependencies.stream()));
     }
 
-    // Finds the first listed protocol from the service that has a
-    // discovered protocol generator that matches the name.
-    private Optional<ProtocolGenerator> getDefaultGenerator() {
-        List<String> protocols = settings.resolveServiceProtocols(service);
-        Map<String, ProtocolGenerator> generators = integrations.stream()
-                .flatMap(integration -> integration.getProtocolGenerators().stream())
-                .collect(Collectors.toMap(ProtocolGenerator::getName, Function.identity()));
-        return protocols.stream()
-                .filter(generators::containsKey)
-                .map(generators::get)
-                .findFirst();
-    }
-
     @Override
     protected Void getDefault(Shape shape) {
         return null;
@@ -249,35 +260,27 @@ public Void serviceShape(ServiceShape shape) {
         for (OperationShape operation : topDownIndex.getContainedOperations(service)) {
             writers.useShapeWriter(operation, commandWriter -> new CommandGenerator(
                     settings, model, operation, symbolProvider, commandWriter,
-                    runtimePlugins, applicationProtocol).run());
+                    runtimePlugins, protocolGenerator, applicationProtocol).run());
         }
 
-        // Generate each protocol.
-        shape.getTrait(ProtocolsTrait.class).ifPresent(protocolsTrait -> {
-            LOGGER.info("Looking for protocol generators for protocols: " + protocolsTrait.getProtocolNames());
-            for (TypeScriptIntegration integration : integrations) {
-                for (ProtocolGenerator generator : integration.getProtocolGenerators()) {
-                    if (protocolsTrait.hasProtocol(generator.getName())) {
-                        LOGGER.info("Generating serde for protocol " + generator.getName() + " on " + shape.getId());
-                        String fileRoot = "protocols/" + ProtocolGenerator.getSanitizedName(generator.getName());
-                        String namespace = "./" + fileRoot;
-                        TypeScriptWriter writer = new TypeScriptWriter(namespace);
-                        ProtocolGenerator.GenerationContext context = new ProtocolGenerator.GenerationContext();
-                        context.setProtocolName(generator.getName());
-                        context.setIntegrations(integrations);
-                        context.setModel(model);
-                        context.setService(shape);
-                        context.setSettings(settings);
-                        context.setSymbolProvider(symbolProvider);
-                        context.setWriter(writer);
-                        generator.generateRequestSerializers(context);
-                        generator.generateResponseDeserializers(context);
-                        generator.generateSharedComponents(context);
-                        fileManifest.writeFile(fileRoot + ".ts", writer.toString());
-                    }
-                }
-            }
-        });
+        if (protocolGenerator != null) {
+            LOGGER.info("Generating serde for protocol " + protocolGenerator.getName() + " on " + shape.getId());
+            String fileRoot = "protocols/" + ProtocolGenerator.getSanitizedName(protocolGenerator.getName());
+            String namespace = "./" + fileRoot;
+            TypeScriptWriter writer = new TypeScriptWriter(namespace);
+            ProtocolGenerator.GenerationContext context = new ProtocolGenerator.GenerationContext();
+            context.setProtocolName(protocolGenerator.getName());
+            context.setIntegrations(integrations);
+            context.setModel(model);
+            context.setService(shape);
+            context.setSettings(settings);
+            context.setSymbolProvider(symbolProvider);
+            context.setWriter(writer);
+            protocolGenerator.generateRequestSerializers(context);
+            protocolGenerator.generateResponseDeserializers(context);
+            protocolGenerator.generateSharedComponents(context);
+            fileManifest.writeFile(fileRoot + ".ts", writer.toString());
+        }
 
         return null;
     }

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/CommandGenerator.java

@@ -47,6 +47,7 @@ final class CommandGenerator implements Runnable {
     private final OperationIndex operationIndex;
     private final Symbol inputType;
     private final Symbol outputType;
+    private final ProtocolGenerator protocolGenerator;
     private final ApplicationProtocol applicationProtocol;
 
     CommandGenerator(
@@ -56,6 +57,7 @@ final class CommandGenerator implements Runnable {
             SymbolProvider symbolProvider,
             TypeScriptWriter writer,
             List<RuntimeClientPlugin> runtimePlugins,
+            ProtocolGenerator protocolGenerator,
             ApplicationProtocol applicationProtocol
     ) {
         this.settings = settings;
@@ -67,6 +69,7 @@ final class CommandGenerator implements Runnable {
         this.runtimePlugins = runtimePlugins.stream()
                 .filter(plugin -> plugin.matchesOperation(model, service, operation))
                 .collect(Collectors.toList());
+        this.protocolGenerator = protocolGenerator;
         this.applicationProtocol = applicationProtocol;
 
         symbol = symbolProvider.toSymbol(operation);
@@ -190,7 +193,6 @@ private void writeSerde() {
                 .write("private serialize(")
                 .indent()
                     .write("input: $T,", inputType)
-                    .write("protocol: string,")
                     .write("context: SerdeContext")
                 .dedent()
                 .openBlock(
@@ -203,33 +205,24 @@ private void writeSerde() {
                 .write("private deserialize(")
                 .indent()
                     .write("output: $T,", applicationProtocol.getResponseType())
-                    .write("protocol: string,")
                     .write("context: SerdeContext")
                 .dedent()
                 .openBlock("): Promise<$T> {", "}", outputType, () -> writeSerdeDispatcher(false))
                 .write("");
     }
 
     private void writeSerdeDispatcher(boolean isInput) {
-        writer.openBlock("switch (protocol) {", "}", () -> {
-            // Generate case statements for each supported protocol.
-            // For example:
-            // case 'aws.rest-json-1.1':
-            //   return getFooCommandAws_RestJson1_1Serialize(input, utils);
-            // TODO Validate this is the right set of protocols; settings.protocols was empty here.
-            for (String protocol : settings.resolveServiceProtocols(service)) {
-                String serdeFunctionName = isInput
-                        ? ProtocolGenerator.getSerFunctionName(symbol, protocol)
-                        : ProtocolGenerator.getDeserFunctionName(symbol, protocol);
-                writer.addImport(serdeFunctionName, serdeFunctionName,
-                        "./protocols/" + ProtocolGenerator.getSanitizedName(protocol));
-                writer.write("case '$L':", protocol)
-                        .write("  return $L($L, context);", serdeFunctionName, isInput ? "input" : "output");
-            }
-
-            writer.write("default:")
-                    .write("  throw new Error(\"Unknown protocol, \" + protocol + \". Expected one of: $L\");",
-                           settings.getProtocols());
-        });
+        // For example:
+        // return getFooCommandAws_RestJson1_1Serialize(input, utils);
+        if (protocolGenerator == null) {
+            writer.write("throw new Error(\"No supported protocol was found\");");
+        } else {
+            String serdeFunctionName = isInput
+                    ? ProtocolGenerator.getSerFunctionName(symbol, protocolGenerator.getName())
+                    : ProtocolGenerator.getDeserFunctionName(symbol, protocolGenerator.getName());
+            writer.addImport(serdeFunctionName, serdeFunctionName,
+                             "./protocols/" + ProtocolGenerator.getSanitizedName(protocolGenerator.getName()));
+            writer.write("return $L($L, context);", serdeFunctionName, isInput ? "input" : "output");
+        }
     }
 }

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/RuntimeConfigGenerator.java

@@ -32,23 +32,20 @@ final class RuntimeConfigGenerator {
     private final Model model;
     private final ServiceShape service;
     private final SymbolProvider symbolProvider;
-    private final String protocolName;
     private final TypeScriptDelegator delegator;
     private final List<TypeScriptIntegration> integrations;
 
     RuntimeConfigGenerator(
             TypeScriptSettings settings,
             Model model,
             SymbolProvider symbolProvider,
-            String protocolName,
             TypeScriptDelegator delegator,
             List<TypeScriptIntegration> integrations
     ) {
         this.settings = settings;
         this.model = model;
         this.service = settings.getService(model);
         this.symbolProvider = symbolProvider;
-        this.protocolName = protocolName;
         this.delegator = delegator;
         this.integrations = integrations;
     }
@@ -58,10 +55,6 @@ void generate(LanguageTarget target) {
         String contents = template
                 .replace("${clientModuleName}", symbolProvider.toSymbol(service).getNamespace())
                 .replace("${apiVersion}", service.getVersion())
-                // Set the protocol to "undefined" if no default protocol can be resolved.
-                // This should only be the case when testing out code generators. The runtime
-                // code is expected to throw an exception when this value is encountered.
-                .replace("${protocol}", protocolName == null ? "undefined" : protocolName)
                 .replace("$", "$$") // sanitize template place holders.
                 .replace("$${customizations}", "${L@customizations}");