1 つの Step で完結するバックエンドフレームワーク Motia を試してみた

npx motia@latest create

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cd my-motia-app
npm run dev

import { randomUUID } from "node:crypto";
 
export interface Todo {
  id: string;
  title: string;
  completed: boolean;
  createdAt: Date;
  updatedAt: Date;
}
 
interface CreateTodoInput {
  title: string;
}
 
interface UpdateTodoInput {
  title?: string;
  completed?: boolean;
}
 
class TodoStore {
  private todos: Map<string, Todo> = new Map();
  addTodo(input: CreateTodoInput): Todo {
    const now = new Date();
    const todo: Todo = {
      id: randomUUID(),
      title: input.title,
      completed: false,
      createdAt: now,
      updatedAt: now,
    };
 
    this.todos.set(todo.id, todo);
    return todo;
  }
 
  getTodos(): Todo[] {
    return Array.from(this.todos.values());
  }
  getTodoById(id: string): Todo | undefined {
    return this.todos.get(id);
  }
  updateTodo(id: string, input: UpdateTodoInput): Todo | null {
    const todo = this.todos.get(id);
    if (!todo) {
      return null;
    }
 
    const updated: Todo = {
      ...todo,
      ...input,
      updatedAt: new Date(),
    };
 
    this.todos.set(id, updated);
    return updated;
  }
 
  /**
   * Delete a TODO item
   */
  deleteTodo(id: string): boolean {
    return this.todos.delete(id);
  }
}
 
export const todoStore = new TodoStore();

import type { ApiRouteConfig, Handlers } from "motia";
import { z } from "zod";
import { todoStore } from "./store";
 
const createTodoRequestSchema = z.object({
  body: z.object({
    title: z.string().min(1).max(255),
  }),
});
 
// config はいつ実行されるかを設定する
// ここでは POST /todos へのリクエストを受け取ったときに実行されるように設定している
export const config: ApiRouteConfig = {
  name: "CreateTodoAPI",
  type: "api",
  path: "/todos",
  method: "POST",
  description:
    "Receives a request to create a new TODO item and emits an event for processing",
  flows: ["todo-creation-flow"],
  emits: [],
  responseSchema: {
    201: z.object({
      id: z.string(),
      title: z.string(),
      completed: z.boolean(),
      createdAt: z.string(),
      updatedAt: z.string(),
    }),
  },
};
 
// ハンドラ関数は実際のリクエスト処理を行う
export const handler: Handlers["CreateTodoAPI"] = async (
  req,
  { logger }
) => {
  // エラーハンドリングは省略
  const data = createTodoRequestSchema.parse(req);
  const todo = todoStore.addTodo(data);
 
  logger.info("New TODO item created", { todoId: todo.id });
 
  return {
    status: 201,
    body: todo,
  };
};

[
  {
    "id": "todo-creation-flow",
    "config": {
      "src/todos/create-todo.step.ts": {
        "x": 0,
        "y": 0
      }
    }
  }
]

import type { ApiRouteConfig, Handlers } from "motia";
import { z } from "zod";
import { todoStore } from "./store";
 
const createTodoRequestSchema = z.object({
  body: z.object({
    title: z.string().min(1).max(255),
  }),
});
 
export const config: ApiRouteConfig = {
  name: "CreateTodoAPI",
  type: "api",
  path: "/todos",
  method: "POST",
  description:
    "Receives a request to create a new TODO item and emits an event for processing",
  flows: ["todo-creation-flow"],
  emits: ["todo-created"],
  responseSchema: {
    201: z.object({
      id: z.string(),
      title: z.string(),
      completed: z.boolean(),
      createdAt: z.string(),
      updatedAt: z.string(),
    }),
  },
};
 
export const handler: Handlers["CreateTodoAPI"] = async (
  req,
  { emit, logger }
) => {
  const data = createTodoRequestSchema.parse(req);
  const todo = todoStore.addTodo(data);
 
  logger.info("New TODO item created", { todoId: todo.id });
 
  await emit({
    topic: "todo-created",
    data: {
      id: todo.id,
      title: todo.title,
    },
  });
 
  logger.info("Emitted 'todo-created' event", { todoId: todo.id });
 
  return {
    status: 201,
    body: todo,
  };
};

import { EventConfig, Handlers } from "motia";
 
export const config: EventConfig = {
  type: "event",
  name: "SendTodoCreationEmail",
  description:
    "Background job that sends an email notification when a new TODO item is created",
  subscribes: ["todo-created"],
  emits: [],
  flows: ["todo-creation-flow"],
};
 
export const handler: Handlers["SendTodoCreationEmail"] = async (
  input,
  { logger }
) => {
  const { id, title } = input;
 
  // 時間がかかる処理をシミュレート
  await new Promise((resolve) => setTimeout(resolve, 2000));
 
  // メール送信ロジックをここに実装する
  logger.info(
    `Sending email notification for new TODO item: [ID: ${id}, Title: ${title}]`
  );
};

motia-developer サブエージェントを使用して、GET /todos エンドポイントを実装してください。すべての TODO アイテムを返す API エンドポイントを作成します。レスポンスは JSON 形式で、各 TODO アイテムには id, title, completed, createdAt, updatedAt フィールドが含まれます。TODO アイテムは src/todos/store.ts の todoStore から取得してください。

import type { ApiRouteConfig, Handlers } from "motia";
import { z } from "zod";
import { todoStore } from "./store.js";
 
export const config: ApiRouteConfig = {
  name: "GetTodosAPI",
  type: "api",
  path: "/todos",
  method: "GET",
  description: "Returns all TODO items from the store",
  flows: ["todo-management"],
  emits: [],
  responseSchema: {
    200: z.array(
      z.object({
        id: z.string(),
        title: z.string(),
        completed: z.boolean(),
        createdAt: z.string(),
        updatedAt: z.string(),
      }),
    ),
  },
};
 
export const handler: Handlers["GetTodosAPI"] = async (req, { logger }) => {
  logger.info("Fetching all TODO items");
 
  const todos = todoStore.getTodos();
 
  logger.info("Retrieved TODO items", { count: todos.length });
 
  return {
    status: 200,
    body: todos.map((todo) => ({
      id: todo.id,
      title: todo.title,
      completed: todo.completed,
      createdAt: todo.createdAt.toISOString(),
      updatedAt: todo.updatedAt.toISOString(),
    })),
  };
};

npx motia rules pull

npm install --save-dev @motiadev/test vitest

"scripts": {
  "test": "vitest"
},

import { createMotiaTester } from "@motiadev/test";
import { describe, it, expect, afterAll } from "vitest";
 
describe("CreateTodo", () => {
  // アプリのテストバージョンを作成
  const tester = createMotiaTester();
 
  afterAll(async () => {
    await tester.close();
  });
 
  it("should create a new todo item", async () => {
    // /todos エンドポイントにPOSTリクエストを送信
    const response = await tester.post("/todos", {
      body: { title: "New Todo Item" },
    });
 
    // レスポンスを検証
    expect(response.status).toBe(201);
    const data = await response.json();
    expect(data).toHaveProperty("id");
    expect(data.title).toBe("New Todo Item");
    expect(data.completed).toBe(false);
  });
 
  it("should emit 'todo-created' event upon creation", async () => {
    // todo-created イベントを監視
    const watcher = await tester.watch("todoCreated");
 
    await tester.post("/todos", {
      body: { title: "Another Todo Item" },
    });
 
    // イベントが発火するのを待つ
    await tester.waitEvents();
 
    // 発火したイベントを検証
    const events = watcher.getCapturedEvents();
    expect(events).toHaveLength(1);
    expect(events[0].data).toMatchObject({
      id: expect.any(String),
      title: "Another Todo Item",
    });
  });
});

import { createMockContext } from "@motiadev/test";
import { handler } from "./send-todo-creation-email.step";
import { describe, it, expect } from "vitest";
 
describe("CreateTodoAPI Handler", () => {
  it("should create a new todo item", async () => {
    const input = {
      id: "test-todo-id",
      title: "Unit Test Todo Item",
    };
 
    const mockContext = createMockContext();
 
    await handler(input, mockContext);
 
    expect(mockContext.logger.info).toHaveBeenCalledWith(
      `Sending email notification for new TODO item: [ID: ${input.id}, Title: ${input.title}]`
    );
  });
});