Implementare l'API del Gioco e il server MCP dell'Inventario

Task 1: Implementare la Game API

Implementeremo le seguenti API in questa sezione:

1. saveGame - crea o aggiorna un gioco.
2. queryGames - restituisce una lista paginata di giochi salvati precedentemente.
3. queryInventory - restituisce una lista paginata degli oggetti nell’inventario di un giocatore.
4. queryActions - restituisce la cronologia delle conversazioni per un dato gioco.

Dove risiede ogni pezzo di stato

• games e inventory sono in DynamoDB (tramite ElectroDB) — le lambda della Game API e il server MCP dell’Inventario li leggono/scrivono.
• actions (trascrizione della chat) è in S3 — l’S3SessionManager dello Story Agent scrive un blob JSON per turno, e queryActions nella Game API li legge in modo che l’UI possa riprodurre la cronologia al ricaricamento della pagina. Non esiste una procedura saveAction; l’agente è l’unico scrittore.

Schema dell’API

Per definire gli input e gli output della nostra API, creiamo il nostro schema utilizzando Zod nel file packages/game-api/src/schema/index.ts come segue:

+

import { z } from 'zod';

export const QueryInputSchema = z.object({
  cursor: z.string().optional(),
  limit: z.number().optional().default(100),
});
export type IQueryInput = z.TypeOf<typeof QueryInputSchema>;

export const ActionSchema = z.object({
  role: z.enum(['user', 'assistant']),
  content: z.string(),
  messageId: z.number(),
});
export type IAction = z.TypeOf<typeof ActionSchema>;

export const GameSchema = z.object({
  playerName: z.string(),
  genre: z.enum(['zombie', 'superhero', 'medieval']),
  lastUpdated: z.iso.datetime(),
});
export type IGame = z.TypeOf<typeof GameSchema>;

export const ItemSchema = z.object({
  playerName: z.string(),
  itemName: z.string(),
  emoji: z.string().optional(),
  lastUpdated: z.iso.datetime(),
  quantity: z.number(),
});
export type IItem = z.TypeOf<typeof ItemSchema>;

export const createPaginatedQueryOutput = <ItemType extends z.ZodTypeAny>(
  itemSchema: ItemType,
) => {
  return z.object({
    items: z.array(itemSchema),
    cursor: z.string().nullable(),
  });
};

+-

export * from './echo.js'
import { z } from 'zod';

export const QueryInputSchema = z.object({
  cursor: z.string().optional(),
  limit: z.number().optional().default(100),
});
export type IQueryInput = z.TypeOf<typeof QueryInputSchema>;

export const ActionSchema = z.object({
  role: z.enum(['user', 'assistant']),
  content: z.string(),
  messageId: z.number(),
});
export type IAction = z.TypeOf<typeof ActionSchema>;

export const GameSchema = z.object({
  playerName: z.string(),
  genre: z.enum(['zombie', 'superhero', 'medieval']),
  lastUpdated: z.iso.datetime(),
});
export type IGame = z.TypeOf<typeof GameSchema>;

export const ItemSchema = z.object({
  playerName: z.string(),
  itemName: z.string(),
  emoji: z.string().optional(),
  lastUpdated: z.iso.datetime(),
  quantity: z.number(),
});
export type IItem = z.TypeOf<typeof ItemSchema>;

export const createPaginatedQueryOutput = <ItemType extends z.ZodTypeAny>(
  itemSchema: ItemType,
) => {
  return z.object({
    items: z.array(itemSchema),
    cursor: z.string().nullable(),
  });
};

Elimina il file packages/game-api/src/schema/echo.ts poiché non lo utilizzeremo in questo progetto.

Inferenza automatica dei tipi

Per ognuno degli schemi che definiamo in Zod, esportiamo anche un’interfaccia utilizzando la sintassi z.TypeOf. Questo converte la nostra definizione Zod in un’interfaccia TypeScript senza duplicare gli sforzi.

Modellazione delle entità

Questo è il diagramma ER per la nostra applicazione.

Il generatore ts#dynamodb ha configurato ElectroDB, che utilizzeremo per modellare i nostri dati. Persisteremo la cronologia delle conversazioni in S3, quindi aggiungiamo una dipendenza sul client S3:

pnpm

pnpm add -w @aws-sdk/client-s3@3.1075.0

yarn

yarn add @aws-sdk/client-s3@3.1075.0

npm

npm install --legacy-peer-deps @aws-sdk/client-s3@3.1075.0

bun

bun install @aws-sdk/client-s3@3.1075.0

Dipendenze root

Tutte le dipendenze vengono aggiunte al file package.json principale poiché @aws/nx-plugin segue il principio della single version policy. Per maggiori informazioni, consulta la guida ts#project.

Sostituisci l’entità di esempio generata in packages/dungeon-db/src/entities/index.ts con le nostre entità Game e Inventory, ed elimina packages/dungeon-db/src/entities/example.ts:

import { Entity } from 'electrodb';
import { getDynamoDBClient, resolveTableName } from '../client.js';

export const createGameEntity = async () =>
  new Entity(
    {
      model: {
        entity: 'Game',
        version: '1',
        service: 'game',
      },
      attributes: {
        playerName: { type: 'string', required: true, readOnly: true },
        genre: { type: 'string', required: true, readOnly: true },
        lastUpdated: {
          type: 'string',
          required: true,
          default: () => new Date().toISOString(),
        },
      },
      indexes: {
        primary: {
          pk: { field: 'pk', composite: ['playerName'] },
          sk: { field: 'sk', composite: [] },
        },
      },
    },
    { client: getDynamoDBClient(), table: await resolveTableName() },
  );

export const createInventoryEntity = async () =>
  new Entity(
    {
      model: {
        entity: 'Inventory',
        version: '1',
        service: 'game',
      },
      attributes: {
        playerName: { type: 'string', required: true, readOnly: true },
        lastUpdated: {
          type: 'string',
          required: true,
          default: () => new Date().toISOString(),
        },
        itemName: {
          type: 'string',
          required: true,
        },
        emoji: {
          type: 'string',
          required: false,
        },
        quantity: {
          type: 'number',
          required: true,
        },
      },
      indexes: {
        primary: {
          pk: { field: 'pk', composite: ['playerName'] },
          sk: { field: 'sk', composite: ['itemName'] },
        },
      },
    },
    { client: getDynamoDBClient(), table: await resolveTableName() },
  );

ElectroDB ci permette non solo di definire i nostri tipi, ma può anche fornire valori predefiniti per certi campi come i timestamp. Inoltre, ElectroDB segue il single-table design, che è la best practice quando si utilizza DynamoDB.

Collezioni ElectroDB

Sebbene ElectroDB supporti le collections, in questo tutorial abbiamo scelto di non utilizzarle per semplicità.

Definizione delle procedure

Per implementare i metodi dell’API, apporta le seguenti modifiche in packages/game-api/src/procedures:

games.ts

import { createGameEntity } from ':dungeon-adventure/dungeon-db';
import {
  GameSchema,
  IGame,
  QueryInputSchema,
  createPaginatedQueryOutput,
} from '../schema/index.js';
import { publicProcedure } from '../init.js';

export const queryGames = publicProcedure
  .input(QueryInputSchema)
  .output(createPaginatedQueryOutput(GameSchema))
  .query(async ({ input }) => {
    const gameEntity = await createGameEntity();
    const result = await gameEntity.scan.go({
      cursor: input.cursor,
      count: input.limit,
    });

    return {
      items: result.data as IGame[],
      cursor: result.cursor,
    };
  });

export const saveGame = publicProcedure
  .input(GameSchema.omit({ lastUpdated: true }))
  .output(GameSchema)
  .mutation(async ({ input }) => {
    const gameEntity = await createGameEntity();

    const result = await gameEntity.put(input).go();
    return result.data as IGame;
  });

inventory.ts

import {
  ItemSchema,
  QueryInputSchema,
  createPaginatedQueryOutput,
} from '../schema/index.js';
import { publicProcedure } from '../init.js';
import { z } from 'zod';
import { createInventoryEntity } from ':dungeon-adventure/dungeon-db';

export const queryInventory = publicProcedure
  .input(QueryInputSchema.extend({ playerName: z.string() }))
  .output(createPaginatedQueryOutput(ItemSchema))
  .query(async ({ input }) => {
    const inventoryEntity = await createInventoryEntity();
    const result = await inventoryEntity.query
      .primary({ playerName: input.playerName })
      .go({ cursor: input.cursor, count: input.limit });

    return {
      items: result.data,
      cursor: result.cursor,
    };
  });

actions.ts

import { publicProcedure } from '../init.js';
import { ActionSchema, IAction } from '../schema/index.js';
import { z } from 'zod';
import {
  S3Client,
  ListObjectsV2Command,
  GetObjectCommand,
} from '@aws-sdk/client-s3';
import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';
import { readFile, readdir } from 'node:fs/promises';
import { join, resolve } from 'node:path';

const resolveSessionsBucket = async (): Promise<string> => {
  const buckets = await getAppConfig('buckets', {
    application: process.env.RUNTIME_CONFIG_APP_ID!,
    environment: 'default',
    transform: 'json',
  });
  const bucket = (buckets as Record<string, any>).StorySessions?.bucketName;
  if (!bucket)
    throw new Error('StorySessions bucket not found in runtime config');
  return bucket;
};

const s3 = new S3Client();
const LOCAL_SESSION_STORAGE_DIR = '/tmp/strands-sessions';

// Matches ``session_<sessionId>/agents/agent_<agentId>/messages/message_<idx>.json``
// written by ``strands.session.S3SessionManager`` on the agent side. We only
// ever care about the default agent id ``default`` that Strands uses when
// none is set explicitly, so hard-code the path prefix the UI needs to list.
const messagesPrefix = (sessionId: string) =>
  `session_${sessionId}/agents/agent_default/messages/`;

const messageIndex = (pathOrKey: string): number => {
  const match = pathOrKey.match(/message_(\d+)\.json$/);
  return match ? Number(match[1]) : Number.MAX_SAFE_INTEGER;
};

const toAction = (body: any): IAction | undefined => {
  const message = body.redact_message ?? body.message;
  const role = message?.role;
  if (role !== 'user' && role !== 'assistant') return undefined;
  const text = Array.isArray(message.content)
    ? message.content
        .filter((b: any) => typeof b?.text === 'string')
        .map((b: any) => b.text)
        .join('')
    : String(message.content ?? '');
  if (!text) return undefined;
  return { role, content: text, messageId: body.message_id };
};

const readLocalActions = async (sessionId: string): Promise<IAction[]> => {
  const baseDir = resolve(LOCAL_SESSION_STORAGE_DIR);
  const messagesDir = resolve(baseDir, messagesPrefix(sessionId));
  if (!messagesDir.startsWith(`${baseDir}/`)) {
    throw new Error('Invalid session id');
  }

  let files: string[];
  try {
    files = await readdir(messagesDir);
  } catch (error: any) {
    if (error?.code === 'ENOENT') return [];
    throw error;
  }

  const actions: IAction[] = [];
  for (const file of files
    .filter((f) => f.endsWith('.json'))
    .sort((a, b) => messageIndex(a) - messageIndex(b))) {
    const body = JSON.parse(await readFile(join(messagesDir, file), 'utf8'));
    const action = toAction(body);
    if (action) actions.push(action);
  }
  return actions;
};

const readS3Actions = async (sessionId: string): Promise<IAction[]> => {
  const bucket = await resolveSessionsBucket();
  const list = await s3.send(
    new ListObjectsV2Command({
      Bucket: bucket,
      Prefix: messagesPrefix(sessionId),
    }),
  );
  const keys = (list.Contents ?? [])
    .map((o) => o.Key!)
    .filter((k) => k.endsWith('.json'))
    .sort((a, b) => messageIndex(a) - messageIndex(b));

  const actions: IAction[] = [];
  for (const key of keys) {
    const obj = await s3.send(
      new GetObjectCommand({ Bucket: bucket, Key: key }),
    );
    const body = JSON.parse(await obj.Body!.transformToString());
    const action = toAction(body);
    if (action) actions.push(action);
  }
  return actions;
};

export const queryActions = publicProcedure
  .input(z.object({ sessionId: z.string() }))
  .output(z.object({ items: z.array(ActionSchema) }))
  .query(async ({ input }) => {
    const actions =
      process.env.LOCAL_DEV === 'true'
        ? await readLocalActions(input.sessionId)
        : await readS3Actions(input.sessionId);
    return { items: actions };
  });

Elimina il file echo.ts (da packages/game-api/src/procedures) poiché non lo utilizzeremo in questo progetto.

Configurazione del router

Dopo aver definito le nostre procedure, per collegarle alla nostra API, aggiorna il seguente file:

packages/game-api/src/router.ts

+

import { t } from './init.js';
import { queryActions } from './procedures/actions.js';
import { queryGames, saveGame } from './procedures/games.js';
import { queryInventory } from './procedures/inventory.js';

export const router = t.router;

export const appRouter = router({
  actions: router({
    query: queryActions,
  }),
  games: router({
    query: queryGames,
    save: saveGame,
  }),
  inventory: router({
    query: queryInventory,
  }),
});

export type AppRouter = typeof appRouter;

+-

import { echo } from './procedures/echo.js';
import { t } from './init.js';
import { queryActions } from './procedures/actions.js';
import { queryGames, saveGame } from './procedures/games.js';
import { queryInventory } from './procedures/inventory.js';

export const router = t.router;

export const appRouter = router({
  echo,
  actions: router({
    query: queryActions,
  }),
  games: router({
    query: queryGames,
    save: saveGame,
  }),
  inventory: router({
    query: queryInventory,
  }),
});

export type AppRouter = typeof appRouter;

Task 2: Creare un server MCP per l’inventario

Creiamo un server MCP che permetterà al nostro agente di gestire gli oggetti nell’inventario di un giocatore.

Definiremo i seguenti strumenti per il nostro agente:

• list-inventory-items per recuperare gli oggetti correnti nell’inventario del giocatore
• add-to-inventory per aggiungere oggetti all’inventario del giocatore
• remove-from-inventory per rimuovere oggetti dall’inventario del giocatore

Per risparmiare tempo, definiremo tutti gli strumenti inline:

packages/inventory/src/mcp-server/server.ts

+

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import z from 'zod';
import { createInventoryEntity } from ':dungeon-adventure/dungeon-db';

/**
 * Create the MCP Server
 */
export const createServer = async () => {
  const server = new McpServer({
    name: 'inventory-mcp-server',
    version: '1.0.0',
  });

  server.registerTool(
    'list-inventory-items',
    {
      description: "List items in the player's inventory. Leave cursor blank unless you are requesting subsequent pages",
      inputSchema: {
        playerName: z.string(),
        cursor: z.string().optional(),
      },
    },
    async ({ playerName }) => {
      const inventory = await createInventoryEntity();
      const results = await inventory.query
        .primary({
          playerName,
        })
        .go();

      return {
        content: [{ type: 'text' as const, text: JSON.stringify(results) }],
      };
    },
  );

  server.registerTool(
    'add-to-inventory',
    {
      description: "Add an item to the player's inventory. Quantity defaults to 1 if omitted.",
      inputSchema: {
        playerName: z.string(),
        itemName: z.string(),
        emoji: z.string(),
        quantity: z.number().optional().default(1),
      },
    },
    async ({ playerName, itemName, emoji, quantity = 1 }) => {
      const inventory = await createInventoryEntity();
      await inventory
        .put({
          playerName,
          itemName,
          quantity,
          emoji,
        })
        .go();

      return {
        content: [
          {
            type: 'text' as const,
            text: `Added ${itemName} (x${quantity}) to inventory`,
          },
        ],
      };
    },
  );

  server.registerTool(
    'remove-from-inventory',
    {
      description: "Remove an item from the player's inventory. If quantity is omitted, all items are removed.",
      inputSchema: {
        playerName: z.string(),
        itemName: z.string(),
        quantity: z.number().optional(),
      },
    },
    async ({ playerName, itemName, quantity }) => {
      const inventory = await createInventoryEntity();

      // If quantity is omitted, remove the entire item
      if (quantity === undefined) {
        try {
          await inventory.delete({ playerName, itemName }).go();
          return {
            content: [
              { type: 'text' as const, text: `${itemName} removed from inventory.` },
            ],
          };
        } catch {
          return {
            content: [
              { type: 'text' as const, text: `${itemName} not found in inventory` },
            ],
          };
        }
      }

      // If quantity is specified, fetch current quantity and update
      const item = await inventory.get({ playerName, itemName }).go();

      if (!item.data) {
        return {
          content: [
            { type: 'text' as const, text: `${itemName} not found in inventory` },
          ],
        };
      }

      const newQuantity = item.data.quantity - quantity;

      if (newQuantity <= 0) {
        await inventory.delete({ playerName, itemName }).go();
        return {
          content: [
            { type: 'text' as const, text: `${itemName} removed from inventory.` },
          ],
        };
      }

      await inventory
        .put({
          playerName,
          itemName,
          quantity: newQuantity,
          emoji: item.data.emoji,
        })
        .go();

      return {
        content: [
          {
            type: 'text' as const,
            text: `Removed ${itemName} (x${quantity}) from inventory. ${newQuantity} remaining.`,
          },
        ],
      };
    },
  );

  return server;
};

+-

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { registerDivideTool } from './tools/divide.js';
import { registerSampleGuidanceResource } from './resources/sample-guidance.js';
import z from 'zod';
import { createInventoryEntity } from ':dungeon-adventure/dungeon-db';

/**
 * Create the MCP Server
 */
export const createServer = async () => {
  const server = new McpServer({
    name: 'inventory-mcp-server',
    version: '1.0.0',
  });

  registerDivideTool(server);
  registerSampleGuidanceResource(server);
  server.registerTool(
    'list-inventory-items',
    {
      description: "List items in the player's inventory. Leave cursor blank unless you are requesting subsequent pages",
      inputSchema: {
        playerName: z.string(),
        cursor: z.string().optional(),
      },
    },
    async ({ playerName }) => {
      const inventory = await createInventoryEntity();
      const results = await inventory.query
        .primary({
          playerName,
        })
        .go();

      return {
        content: [{ type: 'text' as const, text: JSON.stringify(results) }],
      };
    },
  );

  server.registerTool(
    'add-to-inventory',
    {
      description: "Add an item to the player's inventory. Quantity defaults to 1 if omitted.",
      inputSchema: {
        playerName: z.string(),
        itemName: z.string(),
        emoji: z.string(),
        quantity: z.number().optional().default(1),
      },
    },
    async ({ playerName, itemName, emoji, quantity = 1 }) => {
      const inventory = await createInventoryEntity();
      await inventory
        .put({
          playerName,
          itemName,
          quantity,
          emoji,
        })
        .go();

      return {
        content: [
          {
            type: 'text' as const,
            text: `Added ${itemName} (x${quantity}) to inventory`,
          },
        ],
      };
    },
  );

  server.registerTool(
    'remove-from-inventory',
    {
      description: "Remove an item from the player's inventory. If quantity is omitted, all items are removed.",
      inputSchema: {
        playerName: z.string(),
        itemName: z.string(),
        quantity: z.number().optional(),
      },
    },
    async ({ playerName, itemName, quantity }) => {
      const inventory = await createInventoryEntity();

      // If quantity is omitted, remove the entire item
      if (quantity === undefined) {
        try {
          await inventory.delete({ playerName, itemName }).go();
          return {
            content: [
              { type: 'text' as const, text: `${itemName} removed from inventory.` },
            ],
          };
        } catch {
          return {
            content: [
              { type: 'text' as const, text: `${itemName} not found in inventory` },
            ],
          };
        }
      }

      // If quantity is specified, fetch current quantity and update
      const item = await inventory.get({ playerName, itemName }).go();

      if (!item.data) {
        return {
          content: [
            { type: 'text' as const, text: `${itemName} not found in inventory` },
          ],
        };
      }

      const newQuantity = item.data.quantity - quantity;

      if (newQuantity <= 0) {
        await inventory.delete({ playerName, itemName }).go();
        return {
          content: [
            { type: 'text' as const, text: `${itemName} removed from inventory.` },
          ],
        };
      }

      await inventory
        .put({
          playerName,
          itemName,
          quantity: newQuantity,
          emoji: item.data.emoji,
        })
        .go();

      return {
        content: [
          {
            type: 'text' as const,
            text: `Removed ${itemName} (x${quantity}) from inventory. ${newQuantity} remaining.`,
          },
        ],
      };
    },
  );

  return server;
};

Man mano che il numero di strumenti cresce, puoi eventualmente rifattorizzarli in file separati.

Elimina le directory tools e resources in packages/inventory/src/mcp-server poiché non verranno utilizzate.

Task 3: Aggiornare l’infrastruttura

Il costrutto DungeonDb generato da ts#dynamodb fornisce già la nostra tabella, quindi dobbiamo solo istanziarlo nel nostro stack e concedere alla Game API e al server MCP dell’Inventario i permessi di cui hanno bisogno. Aggiorna packages/infra/src/stacks/application-stack.ts come segue:

+

import {
  DungeonDb,
  GameApi,
  GameUI,
  InventoryMcpServer,
  RuntimeConfig,
  StoryAgent,
  UserIdentity,
  suppressRules,
} from ':dungeon-adventure/common-constructs';
import { Stack, StackProps, CfnOutput, RemovalPolicy } from 'aws-cdk-lib';
import {
  BlockPublicAccess,
  Bucket,
  BucketEncryption,
} from 'aws-cdk-lib/aws-s3';
import { Construct } from 'constructs';

export class ApplicationStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);

    const rc = RuntimeConfig.ensure(this);

    const userIdentity = new UserIdentity(this, 'UserIdentity');

    // Sandbox-friendly: allow the table to be deleted with the stack.
    const dungeonDb = new DungeonDb(this, 'DungeonDb', {
      deletionProtection: false,
      removalPolicy: RemovalPolicy.DESTROY,
    });

    // S3 bucket for Strands conversation history. The Story Agent writes each
    // turn via ``S3SessionManager``; the Game API reads them back for replay.
    const storySessions = new Bucket(this, 'StorySessions', {
      encryption: BucketEncryption.S3_MANAGED,
      blockPublicAccess: BlockPublicAccess.BLOCK_ALL,
      enforceSSL: true,
      removalPolicy: RemovalPolicy.DESTROY,
      autoDeleteObjects: true,
    });
    suppressRules(
      storySessions,
      ['CKV_AWS_18', 'CKV_AWS_21'],
      'Access logging and object versioning are unnecessary for ephemeral chat transcripts',
    );
    rc.set('buckets', 'StorySessions', {
      bucketName: storySessions.bucketName,
    });

    const gameApi = new GameApi(this, 'GameApi', {
      integrations: GameApi.defaultIntegrations(this).build(),
    });

    dungeonDb.grantReadData(gameApi.integrations['games.query'].handler);
    dungeonDb.grantReadData(gameApi.integrations['inventory.query'].handler);
    dungeonDb.grantReadWriteData(gameApi.integrations['games.save'].handler);
    storySessions.grantRead(gameApi.integrations['actions.query'].handler);

    const mcpServer = new InventoryMcpServer(this, 'InventoryMcpServer');
    dungeonDb.grantReadWriteData(mcpServer.agentCoreRuntime);

    // Use Cognito for user authentication with the agent
    const storyAgent = new StoryAgent(this, 'StoryAgent', {
      identity: userIdentity,
    });
    storySessions.grantReadWrite(storyAgent);

    new CfnOutput(this, 'StoryAgentArn', {
      value: storyAgent.agentCoreRuntime.agentRuntimeArn,
    });
    new CfnOutput(this, 'InventoryMcpArn', {
      value: mcpServer.agentCoreRuntime.agentRuntimeArn,
    });

    // Grant the agent permissions to invoke our mcp server
    mcpServer.grantInvokeAccess(storyAgent);

    // Grant the authenticated role access to invoke the api
    gameApi.grantInvokeAccess(userIdentity.identityPool.authenticatedRole);

    new GameUI(this, 'GameUI');
  }
}

+-

import {
  DungeonDb,
  GameApi,
  GameUI,
  InventoryMcpServer,
  RuntimeConfig,
  StoryAgent,
  UserIdentity,
  suppressRules,
} from ':dungeon-adventure/common-constructs';
import { Stack, StackProps, CfnOutput } from 'aws-cdk-lib';
import { Stack, StackProps, CfnOutput, RemovalPolicy } from 'aws-cdk-lib';
import {
  BlockPublicAccess,
  Bucket,
  BucketEncryption,
} from 'aws-cdk-lib/aws-s3';
import { Construct } from 'constructs';

export class ApplicationStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);

    const rc = RuntimeConfig.ensure(this);

    const userIdentity = new UserIdentity(this, 'UserIdentity');

    // Sandbox-friendly: allow the table to be deleted with the stack.
    const dungeonDb = new DungeonDb(this, 'DungeonDb', {
      deletionProtection: false,
      removalPolicy: RemovalPolicy.DESTROY,
    });

    // S3 bucket for Strands conversation history. The Story Agent writes each
    // turn via ``S3SessionManager``; the Game API reads them back for replay.
    const storySessions = new Bucket(this, 'StorySessions', {
      encryption: BucketEncryption.S3_MANAGED,
      blockPublicAccess: BlockPublicAccess.BLOCK_ALL,
      enforceSSL: true,
      removalPolicy: RemovalPolicy.DESTROY,
      autoDeleteObjects: true,
    });
    suppressRules(
      storySessions,
      ['CKV_AWS_18', 'CKV_AWS_21'],
      'Access logging and object versioning are unnecessary for ephemeral chat transcripts',
    );
    rc.set('buckets', 'StorySessions', {
      bucketName: storySessions.bucketName,
    });

    const gameApi = new GameApi(this, 'GameApi', {
      integrations: GameApi.defaultIntegrations(this).build(),
    });

    dungeonDb.grantReadData(gameApi.integrations['games.query'].handler);
    dungeonDb.grantReadData(gameApi.integrations['inventory.query'].handler);
    dungeonDb.grantReadWriteData(gameApi.integrations['games.save'].handler);
    storySessions.grantRead(gameApi.integrations['actions.query'].handler);

    const mcpServer = new InventoryMcpServer(this, 'InventoryMcpServer');
    dungeonDb.grantReadWriteData(mcpServer.agentCoreRuntime);

    // Use Cognito for user authentication with the agent
    const storyAgent = new StoryAgent(this, 'StoryAgent', {
      identity: userIdentity,
    });
    storySessions.grantReadWrite(storyAgent);

    new CfnOutput(this, 'StoryAgentArn', {
      value: storyAgent.agentCoreRuntime.agentRuntimeArn,
    });
    new CfnOutput(this, 'InventoryMcpArn', {
      value: mcpServer.agentCoreRuntime.agentRuntimeArn,
    });

    // Grant the agent permissions to invoke our mcp server
    mcpServer.grantInvokeAccess(storyAgent);

    // Grant the authenticated role access to invoke the api
    gameApi.grantInvokeAccess(userIdentity.identityPool.authenticatedRole);

    new GameUI(this, 'GameUI');
  }
}

Procedure isolate

Nota qui che poiché ogni procedura è gestita da una singola funzione lambda, possiamo seguire il principio del minimo privilegio e assegnare solo i permessi di lettura/scrittura necessari in base all’implementazione della procedura.

Configurazione Runtime

Il costrutto DungeonDb registra il nome della tabella deployata nella Configurazione Runtime sotto il namespace dynamodb, memorizzato in AWS AppConfig. La Game API e il server MCP dell’Inventario lo recuperano a runtime utilizzando Lambda Powertools, invece di doverlo passare come variabile d’ambiente. Un vantaggio di questo approccio è che man mano che il numero di tabelle o altri identificatori di infrastruttura cresce, hai bisogno solo di una singola variabile d’ambiente RUNTIME_CONFIG_APP_ID quando esegui contro l’infrastruttura deployata.

Task 4: Testare la Game API localmente

Non c’è bisogno di deployare su AWS per provare la nostra API — il target dev esegue la Game API contro DynamoDB Local. Poiché abbiamo collegato la Game API al progetto DungeonDb nel Modulo 1, questo target avvia anche DynamoDB Local automaticamente.

Prima, correggi eventuali problemi di linting:

pnpm

pnpm lint

yarn

yarn lint

npm

npm run lint

bun

bun lint

Poi compila la codebase:

pnpm

pnpm build

yarn

yarn build

npm

npm run build

bun

bun build

Avviare il server locale

Avvia la Game API localmente con il target dev, che avvia anche DynamoDB Local:

pnpm

pnpm nx dev game-api

yarn

yarn nx dev game-api

npm

npx nx dev game-api

bun

bunx nx dev game-api

Prima esecuzione

La prima esecuzione scarica l’immagine del container di DynamoDB Local, il che potrebbe richiedere un momento. Lascia il server in esecuzione in questo terminale e apri un secondo terminale per i comandi curl qui sotto.

Testare l’API

Una volta avviato il server, interroga la lista (vuota) dei giochi:

curl -X GET 'http://localhost:2022/games.query?input=%7B%7D'

Codifica URL

Il %7B%7D che passiamo per testare l’API è un oggetto JSON vuoto ({}) codificato in URI.

Vedrai una lista vuota:

{"result":{"data":{"items":[],"cursor":null}}}

Ora salva un gioco:

curl -X POST 'http://localhost:2022/games.save' \
  -H 'Content-Type: application/json' \
  -d '{"playerName":"Alice","genre":"zombie"}'

Il salvataggio restituisce il gioco persistito (con il timestamp lastUpdated che l’entità imposta per te):

{"result":{"data":{"playerName":"Alice","genre":"zombie","lastUpdated":"..."}}}

Interroga di nuovo per confermare che è stato persistito in DynamoDB Local:

curl -X GET 'http://localhost:2022/games.query?input=%7B%7D'

Questa risposta ora include il gioco salvato:

{"result":{"data":{"items":[{"playerName":"Alice","genre":"zombie","lastUpdated":"..."}],"cursor":null}}}

Puoi fermare il server locale (Ctrl+C) una volta terminato.

Task 5: Testare il server MCP dell’Inventario localmente

Possiamo provare gli strumenti del server MCP con l’MCP Inspector utilizzando il target mcp-server-inspect generato:

pnpm

pnpm nx mcp-server-inspect inventory

yarn

yarn nx mcp-server-inspect inventory

npm

npx nx mcp-server-inspect inventory

bun

bunx nx mcp-server-inspect inventory

Questo serve il server MCP localmente (avviando anche DynamoDB Local) e lancia l’MCP Inspector su http://localhost:6274 pre-configurato per connettersi ad esso. Fai clic su Connect, passa alla scheda Tools, fai clic su List Tools, e prova add-to-inventory (ad es. playerName: Alice, itemName: Rusty Sword, emoji: ⚔️) seguito da list-inventory-items per vederlo persistito in DynamoDB Local. Ferma il server (Ctrl+C) quando hai finito.

Complimenti, hai costruito e testato la tua prima API tRPC e il server MCP contro una tabella DynamoDB locale! 🎉🎉🎉🎉🎉