Configurando Azure Functions para Acesso Eficiente a Filas do Azure com SOLID e Padrão Factory em TypeScript

Este é o terceiro artigo de uma série sobre como configurar Azure Functions para acesso a serviços do Azure utilizando os princípios SOLID (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion). Nos artigos anteriores, abordamos o acesso ao Azure Blob Storage e às tabelas do Azure. Neste artigo, focaremos no acesso a filas do Azure utilizando o Azure Storage Queue. Caso sinta vontade de entender como integrar o Azure Table Storage veja o artigo abaixo:

Configurando Azure Functions para Acesso a Tabelas do Azure com Padrão Factory e SOLID em…

Passo 1: Configuração do Ambiente

Antes de começar, certifique-se de ter as seguintes dependências instaladas:

npm install @azure/identity @azure/storage-queue

OBS: Caso precise ver os Passos 1 ao 3 veja o artigo anterior sobre o tema:

Como Configurar o Azure Blob Service Client Aplicando os Princípios SOLID em uma Azure Function…

Passo 4: Criando a Fábrica QueueServiceClientFactory

Implementaremos uma fábrica para criar instâncias de QueueServiceClient com base no provedor de credenciais selecionado.

import { QueueServiceClient } from "@azure/storage-queue";

/**
 * Factory for creating instances of QueueServiceClient.
 */
class QueueServiceClientFactory {
  private accountUrl: string;
  private credentialProvider: CredentialProvider;

  /**
   * Creates an instance of QueueServiceClientFactory.
   * @param {string} accountUrl - The account URL for the QueueServiceClient.
   * @param {CredentialProvider} credentialProvider - The provider for Azure credentials.
   */
  constructor(accountUrl: string, credentialProvider: CredentialProvider) {
    this.accountUrl = accountUrl;
    this.credentialProvider = credentialProvider;
  }

  /**
   * Creates a QueueServiceClient instance.
   * @returns {QueueServiceClient} The QueueServiceClient instance.
   */
  createQueueServiceClient(): QueueServiceClient {
    const credential = this.credentialProvider.getCredential();
    return new QueueServiceClient(this.accountUrl, credential);
  }
}

Passo 5: Utilizando a Fábrica em uma Azure Function

Vamos aplicar nossa fábrica dentro de Azure Functions para acesso seguro e eficiente às filas do Azure.

Exemplo 1: Azure Function com Managed Identity Atribuída ao Sistema

import { AzureFunction, Context, HttpRequest } from "@azure/functions";
import { QueueServiceClientFactory } from "./QueueServiceClientFactory";
import { SystemAssignedManagedIdentityCredentialProvider } from "./SystemAssignedManagedIdentityCredentialProvider";

/**
 * Azure Function triggered by an HTTP request.
 * @param {Context} context - The Azure Function context object.
 * @param {HttpRequest} req - The HTTP request object.
 */
const httpTrigger: AzureFunction = async function (context: Context, req: HttpRequest): Promise<void> {
  const accountUrl = process.env.AZURE_STORAGEQUEUE_RESOURCEENDPOINT;
  const credentialProvider = new SystemAssignedManagedIdentityCredentialProvider();
  const queueServiceClientFactory = new QueueServiceClientFactory(accountUrl, credentialProvider);
  
  const queueServiceClient = queueServiceClientFactory.createQueueServiceClient();
  const queueClient = queueServiceClient.getQueueClient(queueName);
  await queueClient.sendMessage("Hello World!");
  
  context.res = {
    status: 200,
    body: { text: "menssage sent" }
  };
};

export default httpTrigger;

Exemplo 2: Azure Function com Managed Identity Atribuída ao Usuário

import { AzureFunction, Context, HttpRequest } from "@azure/functions";
import { QueueServiceClientFactory } from "./QueueServiceClientFactory";
import { UserAssignedManagedIdentityCredentialProvider } from "./UserAssignedManagedIdentityCredentialProvider";

/**
 * Azure Function triggered by an HTTP request.
 * @param {Context} context - The Azure Function context object.
 * @param {HttpRequest} req - The HTTP request object.
 */
const httpTrigger: AzureFunction = async function (context: Context, req: HttpRequest): Promise<void> {
  const accountUrl = process.env.AZURE_STORAGEQUEUE_RESOURCEENDPOINT;
  const clientId = process.env.AZURE_STORAGEQUEUE_CLIENTID;
  const credentialProvider = new UserAssignedManagedIdentityCredentialProvider(clientId);
  const queueServiceClientFactory = new QueueServiceClientFactory(accountUrl, credentialProvider);
  
  const queueServiceClient = queueServiceClientFactory.createQueueServiceClient();
  const queueClient = queueServiceClient.getQueueClient(queueName);
  await queueClient.sendMessage("Hello World!");
  
  context.res = {
    status: 200,
    body: { text: "menssage sent" }
  };
};

export default httpTrigger;

Exemplo 3: Azure Function com Service Principal

import { AzureFunction, Context, HttpRequest } from "@azure/functions";
import { QueueServiceClientFactory } from "./QueueServiceClientFactory";
import { ServicePrincipalCredentialProvider } from "./ServicePrincipalCredentialProvider";

/**
 * Azure Function triggered by an HTTP request.
 * @param {Context} context - The Azure Function context object.
 * @param {HttpRequest} req - The HTTP request object.
 */
const httpTrigger: AzureFunction = async function (context: Context, req: HttpRequest): Promise<void> {
  const accountUrl = process.env.AZURE_STORAGEQUEUE_RESOURCEENDPOINT;
  const tenantId = process.env.AZURE_STORAGEQUEUE_TENANTID;
  const clientId = process.env.AZURE_STORAGEQUEUE_CLIENTID;
  const clientSecret = process.env.AZURE_STORAGEQUEUE_CLIENTSECRET;
  const credentialProvider = new ServicePrincipalCredentialProvider(tenantId, clientId, clientSecret);
  const queueServiceClientFactory = new QueueServiceClientFactory(accountUrl, credentialProvider);
  
  const queueServiceClient = queueServiceClientFactory.createQueueServiceClient();
  const queueClient = queueServiceClient.getQueueClient(queueName);
  await queueClient.sendMessage("Hello World!");
  
  context.res = {
    status: 200,
    body: { text: "menssage sent" }
  };
};

export default httpTrigger;

Conclusão

Neste artigo, discutimos como configurar e utilizar Azure Functions para interação com filas do Azure, seguindo os princípios SOLID utilizando Factory Pattern. Ao modularizar a obtenção de credenciais e a criação de clientes de serviço, facilitamos a manutenção e expansão do código em cenários de autenticação diversificados.

Referências

Início Rápido - Criar uma conexão de serviço no aplicativo de funções por meio do portal do Azure