Migration of GraphQL todo example app to guide (#822)

* Migration of GraphQL todo example app to guide

See: micronaut-projects/micronaut-graphql#242
Relates to: micronaut-projects/micronaut-graphql#241

* remove tags and add languages to metadata.json

* Add todo graphql guide and add tests

* Switch to postgres and Flyway

* Update screenshot to new ID format

* More asciidoc work

* Polish

* Further cleanups...

* Address feedback

* use common flyway

* use common test

* use callouts

Co-authored-by: Tim Yates <[email protected]>

buildSrc/src/main/java/io/micronaut/guides/Category.java

@@ -6,6 +6,7 @@ public enum Category {
     EMAIL("Email"),
     DATA_ACCESS("Data Access"),
     CACHE("Cache"),
+    GRAPHQL("GraphQL"),
     MESSAGING("Messaging"),
     SECURITY("Micronaut Security"),
     SERVICE_DISCOVERY("Service Discovery"),

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/Author.java

@@ -0,0 +1,36 @@
+package example.micronaut;
+
+import io.micronaut.data.annotation.GeneratedValue;
+import io.micronaut.data.annotation.Id;
+import io.micronaut.data.annotation.MappedEntity;
+
+import javax.validation.constraints.NotNull;
+
+import static io.micronaut.data.annotation.GeneratedValue.Type.AUTO;
+
+@MappedEntity // <1>
+public class Author {
+
+    @Id // <1>
+    @GeneratedValue(AUTO)
+    private Long id;
+
+    @NotNull
+    private final String username;
+
+    public Author(@NotNull String username) {
+        this.username = username;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/AuthorDataFetcher.java

@@ -0,0 +1,19 @@
+package example.micronaut;
+
+import graphql.schema.DataFetcher;
+import graphql.schema.DataFetchingEnvironment;
+import jakarta.inject.Singleton;
+import org.dataloader.DataLoader;
+
+import java.util.concurrent.CompletionStage;
+
+@Singleton // <1>
+public class AuthorDataFetcher implements DataFetcher<CompletionStage<Author>> {
+
+    @Override
+    public CompletionStage<Author> get(DataFetchingEnvironment environment) {
+        ToDo toDo = environment.getSource();
+        DataLoader<Long, Author> authorDataLoader = environment.getDataLoader("author"); // <2>
+        return authorDataLoader.load(toDo.getAuthorId());
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/AuthorDataLoader.java

@@ -0,0 +1,39 @@
+package example.micronaut;
+
+import io.micronaut.scheduling.TaskExecutors;
+import jakarta.inject.Named;
+import jakarta.inject.Singleton;
+import org.dataloader.MappedBatchLoader;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ExecutorService;
+import java.util.function.Function;
+
+import static java.util.stream.Collectors.toMap;
+
+@Singleton // <1>
+public class AuthorDataLoader implements MappedBatchLoader<Long, Author> {
+
+    private final AuthorRepository authorRepository;
+    private final ExecutorService executor;
+
+    public AuthorDataLoader(AuthorRepository authorRepository,
+                            @Named(TaskExecutors.IO) ExecutorService executor) {
+        this.authorRepository = authorRepository;
+        this.executor = executor;
+    }
+
+    @Override
+    public CompletionStage<Map<Long, Author>> load(Set<Long> keys) {
+        return CompletableFuture.supplyAsync(() -> authorRepository
+                        .findByIdIn(keys)
+                        .stream()
+                        .collect(toMap(Author::getId, Function.identity())),
+                executor
+        );
+    }
+
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/AuthorRepository.java

@@ -0,0 +1,21 @@
+package example.micronaut;
+
+import io.micronaut.data.jdbc.annotation.JdbcRepository;
+import io.micronaut.data.repository.CrudRepository;
+
+import java.util.Collection;
+import java.util.Optional;
+
+import static io.micronaut.data.model.query.builder.sql.Dialect.POSTGRES;
+
+@JdbcRepository(dialect = POSTGRES) // <1>
+public interface AuthorRepository extends CrudRepository<Author, Long> { // <2>
+
+    Optional<Author> findByUsername(String username); // <3>
+
+    Collection<Author> findByIdIn(Collection<Long> ids); // <4>
+
+    default Author findOrCreate(String username) { // <5>
+        return findByUsername(username).orElseGet(() -> save(new Author(username)));
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/CompleteToDoDataFetcher.java

@@ -0,0 +1,30 @@
+package example.micronaut;
+
+import graphql.schema.DataFetcher;
+import graphql.schema.DataFetchingEnvironment;
+import jakarta.inject.Singleton;
+
+@Singleton // <1>
+public class CompleteToDoDataFetcher implements DataFetcher<Boolean> {
+
+    private final ToDoRepository toDoRepository;
+
+    public CompleteToDoDataFetcher(ToDoRepository toDoRepository) { // <2>
+        this.toDoRepository = toDoRepository;
+    }
+
+    @Override
+    public Boolean get(DataFetchingEnvironment env) {
+        long id = Long.parseLong(env.getArgument("id"));
+        return toDoRepository
+                .findById(id) // <3>
+                .map(this::setCompletedAndUpdate)
+                .orElse(false);
+    }
+
+    private boolean setCompletedAndUpdate(ToDo todo) {
+        todo.setCompleted(true); // <4>
+        toDoRepository.update(todo); // <5>
+        return true;
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/CreateToDoDataFetcher.java

@@ -0,0 +1,32 @@
+package example.micronaut;
+
+import graphql.schema.DataFetcher;
+import graphql.schema.DataFetchingEnvironment;
+import jakarta.inject.Singleton;
+import javax.transaction.Transactional;
+
+@Singleton // <1>
+public class CreateToDoDataFetcher implements DataFetcher<ToDo> {
+
+    private final ToDoRepository toDoRepository;
+    private final AuthorRepository authorRepository;
+
+    public CreateToDoDataFetcher(ToDoRepository toDoRepository, // <2>
+                                 AuthorRepository authorRepository) {
+        this.toDoRepository = toDoRepository;
+        this.authorRepository = authorRepository;
+    }
+
+    @Override
+    @Transactional
+    public ToDo get(DataFetchingEnvironment env) {
+        String title = env.getArgument("title");
+        String username = env.getArgument("author");
+
+        Author author = authorRepository.findOrCreate(username); // <3>
+
+        ToDo toDo = new ToDo(title, author.getId());
+
+        return toDoRepository.save(toDo); // <4>
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/DataLoaderRegistryFactory.java

@@ -0,0 +1,29 @@
+package example.micronaut;
+
+import io.micronaut.context.annotation.Factory;
+import io.micronaut.runtime.http.scope.RequestScope;
+import org.dataloader.DataLoader;
+import org.dataloader.DataLoaderRegistry;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Factory // <1>
+public class DataLoaderRegistryFactory {
+
+    private static final Logger LOG = LoggerFactory.getLogger(DataLoaderRegistryFactory.class);
+
+    @SuppressWarnings("unused")
+    @RequestScope // <2>
+    public DataLoaderRegistry dataLoaderRegistry(AuthorDataLoader authorDataLoader) {
+        DataLoaderRegistry dataLoaderRegistry = new DataLoaderRegistry();
+        dataLoaderRegistry.register(
+                "author",
+                DataLoader.newMappedDataLoader(authorDataLoader)
+        ); // <3>
+
+        LOG.trace("Created new data loader registry");
+
+        return dataLoaderRegistry;
+    }
+
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/GraphQLFactory.java

@@ -0,0 +1,60 @@
+package example.micronaut;
+
+import graphql.GraphQL;
+import graphql.schema.GraphQLSchema;
+import graphql.schema.idl.RuntimeWiring;
+import graphql.schema.idl.SchemaGenerator;
+import graphql.schema.idl.SchemaParser;
+import graphql.schema.idl.TypeDefinitionRegistry;
+import graphql.schema.idl.errors.SchemaMissingError;
+import io.micronaut.context.annotation.Bean;
+import io.micronaut.context.annotation.Factory;
+import io.micronaut.core.io.ResourceResolver;
+import jakarta.inject.Singleton;
+
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
+@Factory // <1>
+public class GraphQLFactory {
+
+    @Singleton // <2>
+    public GraphQL graphQL(ResourceResolver resourceResolver,
+                           ToDosDataFetcher toDosDataFetcher,
+                           CreateToDoDataFetcher createToDoDataFetcher,
+                           CompleteToDoDataFetcher completeToDoDataFetcher,
+                           AuthorDataFetcher authorDataFetcher) {
+        SchemaParser schemaParser = new SchemaParser();
+        SchemaGenerator schemaGenerator = new SchemaGenerator();
+
+        // Load the schema
+        InputStream schemaDefinition = resourceResolver
+                .getResourceAsStream("classpath:schema.graphqls")
+                .orElseThrow(SchemaMissingError::new);
+
+        // Parse the schema and merge it into a type registry
+        TypeDefinitionRegistry typeRegistry = new TypeDefinitionRegistry();
+        typeRegistry.merge(schemaParser.parse(new BufferedReader(new InputStreamReader(schemaDefinition))));
+
+        // Create the runtime wiring.
+        RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring()
+                .type("Query", typeWiring -> typeWiring  // <3>
+                        .dataFetcher("toDos", toDosDataFetcher))
+
+                .type("Mutation", typeWiring -> typeWiring // <4>
+                        .dataFetcher("createToDo", createToDoDataFetcher)
+                        .dataFetcher("completeToDo", completeToDoDataFetcher))
+
+                .type("ToDo", typeWiring -> typeWiring // <5>
+                        .dataFetcher("author", authorDataFetcher))
+
+                .build();
+
+        // Create the executable schema.
+        GraphQLSchema graphQLSchema = schemaGenerator.makeExecutableSchema(typeRegistry, runtimeWiring);
+
+        // Return the GraphQL bean.
+        return GraphQL.newGraphQL(graphQLSchema).build();
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/ToDo.java

@@ -0,0 +1,57 @@
+package example.micronaut;
+
+import io.micronaut.data.annotation.GeneratedValue;
+import io.micronaut.data.annotation.Id;
+import io.micronaut.data.annotation.MappedEntity;
+
+import javax.validation.constraints.NotNull;
+
+import static io.micronaut.data.annotation.GeneratedValue.Type.AUTO;
+
+@MappedEntity // <1>
+public class ToDo {
+
+    @Id // <2>
+    @GeneratedValue(AUTO)
+    private Long id;
+
+    @NotNull
+    private String title;
+
+    private boolean completed;
+
+    private final long authorId;
+
+    public ToDo(String title, long authorId) {
+        this.title = title;
+        this.authorId = authorId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public boolean isCompleted() {
+        return completed;
+    }
+
+    public void setCompleted(boolean completed) {
+        this.completed = completed;
+    }
+
+    public long getAuthorId() {
+        return authorId;
+    }
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/ToDoRepository.java

@@ -0,0 +1,11 @@
+package example.micronaut;
+
+import io.micronaut.data.jdbc.annotation.JdbcRepository;
+import io.micronaut.data.model.query.builder.sql.Dialect;
+import io.micronaut.data.repository.PageableRepository;
+
+import static io.micronaut.data.model.query.builder.sql.Dialect.POSTGRES;
+
+@JdbcRepository(dialect = POSTGRES) // <1>
+public interface ToDoRepository extends PageableRepository<ToDo, Long> { // <2>
+}

guides/micronaut-graphql-todo/java/src/main/java/example/micronaut/ToDosDataFetcher.java

@@ -0,0 +1,20 @@
+package example.micronaut;
+
+import graphql.schema.DataFetcher;
+import graphql.schema.DataFetchingEnvironment;
+import jakarta.inject.Singleton;
+
+@Singleton // <1>
+public class ToDosDataFetcher implements DataFetcher<Iterable<ToDo>> {
+
+    private final ToDoRepository toDoRepository;
+
+    public ToDosDataFetcher(ToDoRepository toDoRepository) { // <2>
+        this.toDoRepository = toDoRepository;
+    }
+
+    @Override
+    public Iterable<ToDo> get(DataFetchingEnvironment env) {
+        return toDoRepository.findAll();
+    }
+}