Firebase Cloud Functions Firestore トリガーが次のエラーを出力します: エラー: 7 PERMISSION_DENIED: 権限が不足しているか不十分です 質問する

機能コード:

import * as functions from "firebase-functions";
import * as admin from "firebase-admin";

admin.initializeApp();
const settings = { timestampsInSnapshots: true };
admin.firestore().settings(settings);

export const onDocUpdate = functions.firestore
  .document("documents/{documentId}")
  .onUpdate((snapshot, context) => {
    console.log("onDocUpdate called ", context.params.documentId);
    const document = snapshot.after.data();
    console.log("Document: ", document);
    if (document.screw) {
      console.log("Document screw exists. ", document.screw);
      const docRef = admin
        .firestore()
        .collection("screws")
        .doc(document.screw);
      return docRef
        .get()
        .then(doc => {
          if (doc.exists) {
            console.log("Screw for document exists.");
          } else {
            console.error(
              "Screw for document not found! ",
              document.screw
            );
          }
        })
        .catch(error => {
          // Here I get the permission error :(
          console.error(
            "Screw for document doc load error!! ",
            error
          );
        });
    } else {
      console.error("Document is not bound to a screw! ", document.id);
    }
    return null;
  });

{
  "name": "functions",
  "scripts": {
    "lint": "tslint --project tsconfig.json",
    "build": "tsc",
    "serve": "npm run build && firebase serve --only functions",
    "shell": "npm run build && firebase functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "main": "lib/index.js",
  "dependencies": {
    "@google-cloud/firestore": "^0.16.0",
    "firebase-admin": "^6.0.0",
    "firebase-functions": "^2.0.4",
    "protobufjs": "^6.8.8"
  },
  "devDependencies": {
    "tslint": "~5.8.0",
    "typescript": "~2.8.3"
  },
  "private": true
}