Nest.js GraphQL Schema 在构建期间生成答案

【问题标题】：Nest.js GraphQL Schema generation during buildNest.js GraphQL Schema 在构建期间生成
【发布时间】：2021-07-21 16:50:27
【问题描述】：

我在 NestJS 中使用代码优先的 GraphQL 方法，并使用 Nx 设置了 monorepo。

schema.gql 仅在我运行服务器时生成，而在 CI 期间我无法执行此操作。将整个存储库复制到 docker 映像中并启动服务器对我来说是不切实际的。构建嵌套应用程序时不会生成schema.gql。

我还查看了 NestJS 网站上的 Generating the SDL manually 文档，但不确定如何集成该脚本。

只是想知道是否有人在不启动服务器的情况下设法生成了架构？

【问题讨论】：

标签： graphql nestjs

【解决方案1】：

设法弄清楚如何集成Generating the SDL manually。

只需在启动嵌套服务器之前执行生成 SDL 函数即可。

下面包含一个完整的示例。

const resolvers = [MyResolver]

/**
 * Generate GraphQL schema manually. NestJS does not generate the GraphQL schema
 * automatically during the build process and it doesn't generate the GraphQL
 * schema when starting the built app. This schema needs to be generated or
 * the GraphQL api would have nothing to use.
 *
 * @param {MyServices} serviceName - Name of the gavel service to generate a unique
 * schema.
 * @param {Function[]} resolvers - List of GraphQL resolvers being used in that app.
 * @returns {Promise<void>} Nothing gets returned. It will just write the schema and
 * throw an error if it fails.
 */
export async function generateGraphQLSchema(
  serviceName: MyServices,
  resolvers: Function[],
): Promise<void> {
  const app = await NestFactory.create(GraphQLSchemaBuilderModule)
  await app.init()

  const gqlSchemaFactory = app.get(GraphQLSchemaFactory)
  const schema = await gqlSchemaFactory.create(resolvers)

  writeFileSync(join(process.cwd(), `/${serviceName}-schema.gql`), printSchema(schema))
}

/**
 * Setup nest application.
 *
 * @param {string} port - Port the application should listen to.
 * @param {unknown} appModule - Main app module from a nest application.
 * @param {MyServices} serviceName - Name of the gavel service to generate a unique
 * schema.
 * @returns {Promise<void>}
 */
async function bootstrap(port: string, appModule: any, serviceName: MyServices): Promise<void> {
  const app = await NestFactory.create(appModule)

  // Endpoint prefix
  const globalPrefix = `${config.get(`env`)}/v1/${serviceName}`
  app.setGlobalPrefix(globalPrefix)

  // Start Server
  await app.listen(port, () => {
    Logger.log(`Listening at http://localhost:${port}/${globalPrefix}/graphql`)
  })
}

/**
 * Helper to crate standard Nest JS Server.
 *
 * @param {MyServices} serviceName - Name of service.
 * @param {unknown} appModule - Main app module from a nest application.
 */
export function initializeServer(serviceName: GavelService, appModule: any): void {
  const environment = config.get(`env`)
  const port = config.get(`port`)
  initializeElasticApm(`service-${serviceName}`, {
    framework: `nest`,
    environment,
    version: `${packageJson.version}`,
  })
  bootstrap(port, appModule, serviceName).catch((error) => {
    const logger = getElasticSearchLogger(serviceName)
    logger.error(
      { error, environment: config.get(`env`), applicationName: serviceName },
      error.message,
    )
  })
}

generateGraphQLSchema(MyServices.SERVICE_A, resolvers)
  .then(() => initializeServer(MyServices.SERVICE_A, AppModule))
  .catch((e) => console.error(e))

【讨论】：

【解决方案2】：

以下内容对我来说效果很好。我在这里的文档中发现了这一点：

https://docs.nestjs.com/graphql/quick-start#accessing-generated-schema

我添加了一个检查以查看 ENV 是否是生产环境，因为在开发模式下我希望文件生成的位置确实存在。

import { NestFactory } from '@nestjs/core';
import { GraphQLSchemaHost } from '@nestjs/graphql';
import { writeFileSync } from 'fs';
import { printSchema } from 'graphql';
import { join } from 'path';
import { ServerModule } from './server.module';

async function bootstrap() {
  const app = await NestFactory.create(ServerModule);
  await app.listen(process.env.PORT || 3001);

  if (process.env.NODE_ENV === 'production') {
    const { schema } = app.get(GraphQLSchemaHost);
    writeFileSync(join(process.cwd(), `/src/schema.gql`), printSchema(schema));
  }
}
bootstrap();

【讨论】：