我希望在NodeJS中的GraphQl Apollo服务器中的头值，为此我在其中使用了上下文函数，但它运行了无限次。
在控制台中无限打印“abcd”。
控制台：

代码：

const server = new ApolloServer({
  schema: buildSubgraphSchema([{ typeDefs, resolvers }]),
  context:((req)=>{
    // some code
    console.log("abcd");
    return "hello"
  })
});

整个服务器文件：

const dotenv = require('dotenv')
dotenv.config({ path: './.env' })
const mongoose = require("mongoose");
const { typeDefs } = require("./schema/user");
const { resolvers } = require("./resolvers/resolver");
const { ApolloServer } = require("apollo-server");
const {buildSubgraphSchema} = require('@apollo/subgraph')

const server = new ApolloServer({
  schema: buildSubgraphSchema([{ typeDefs, resolvers }]),
  context:((req)=>{
    // some code
    console.log("abcd");
    return "hello"
  })
});

const PORT = process.env.PORT || 5000;
mongoose.connect(
  process.env.MONGO_URI,
  { useNewUrlParser: true }
);
const db = mongoose.connection;
db.on("error", console.error.bind(console, "connection error:"));
db.once("open", function () {
  console.log("Connected to MongoDB");
  server.listen(PORT, () => console.log(`Server started on port ${PORT}`));
});