Setting a DocumentReference in Document on Firesto

问题:

I am trying to create a doc with a reference on Firestore with NodeJS v8.6.0. Like this

const admin = require('firebase-admin')
admin.initializeApp({ credential: MY_CREDENTIAL, databaseURL: MY_DB_URL })
const db = admin.firestore()

const ref = db.doc('foo/someDoc')
db.doc('bar/targetDoc').set({ link: ref })

Although ref is a DocumentReference, it results

Error: Argument "data" is not a valid Document. Input object is deeper than 20 levels or contains a cycle.

Is there anyway to do it on NodeJS (Admin)SDK?

---

In addition, the package used in the code is

"firebase-admin": "^5.4.1"

and

console.log(ref)

outputs

DocumentReference {
  _firestore: 
   Firestore {
     makeAuthenticatedRequest: 
      { [Function: makeAuthenticatedRequest]
        getCredentials: [Function: bound getCredentials],
        authClient: [Object] },
     authClient: 
      Auth {
        authClientPromise: null,
        authClient: null,
        config: [Object],
        environment: {} },
     baseUrl: undefined,
     getCredentials: [Function: bound getCredentials],
     globalInterceptors: [],
     interceptors: [],
     packageJson: 
      { name: '@google-cloud/firestore',
        version: '0.8.1',
        author: 'Google Inc.',
        description: 'Firestore Client Library for Node.js',
        contributors: [Array],
        main: './src/index.js',
        files: [Array],
        repository: 'googleapis/nodejs-firestore',
        keywords: [Array],
        dependencies: [Object],
        devDependencies: [Object],
        scripts: [Object],
        license: 'Apache-2.0',
        engines: [Object],
        types: './types/firestore.d.ts' },
     projectId: 'MY_PROJECT',
     projectIdRequired: true,
     Promise: [Function: Promise],
     grpcMetadata: Metadata { _internal_repr: [Object] },
     maxRetries: undefined,
     userAgent: 'gcloud-node-firestore/0.8.1',
     activeServiceMap_: Map {},
     protos: {},
     _preferTransactions: false,
     _lastSuccessfulRequest: null,
     api: { Firestore: [Object] },
     _referencePath: 
      ResourcePath {
        segments: [],
        _formattedName: undefined,
        _projectId: 'dewpod-dev',
        _databaseId: '(default)' },
     app: 
      FirebaseApp {
        firebaseInternals_: [Object],
        services_: [Object],
        isDeleted_: false,
        name_: '[DEFAULT]',
        options_: [Object],
        database: [Function: bound ],
        auth: [Function: bound ],
        messaging: [Function: bound ],
        storage: [Function: bound ],
        firestore: [Function: bound ],
        INTERNAL: [Object] },
     INTERNAL: FirestoreInternals {} },
  _referencePath: 
   ResourcePath {
     segments: [ 'orgs', 'fooOrg' ],
     _formattedName: undefined,
     _projectId: 'dewpod-dev',
     _databaseId: '(default)' } }

and the full error message is

/SOME_PATH/node_modules/@google-cloud/firestore/src/validate.js:86
        throw new Error(message);
        ^

Error: Argument "data" is not a valid Document. Input object is deeper than 20 levels or contains a cycle.
    at Object.exports.(anonymous function) [as isDocument] (/SOME_PATH/node_modules/@google-cloud/firestore/src/validate.js:86:15)
    at WriteBatch.set (/SOME_PATH/node_modules/@google-cloud/firestore/src/write-batch.js:251:14)
    at DocumentReference.set (/SOME_PATH/node_modules/@google-cloud/firestore/src/reference.js:416:8)
    at Object.<anonymous> (/SOME_PATH/fstest.js:17:20)
    at Module._compile (module.js:624:30)
    at Object.Module._extensions..js (module.js:635:10)
    at Module.load (module.js:545:32)
    at tryModuleLoad (module.js:508:12)
    at Function.Module._load (module.js:500:3)
    at Function.Module.runMain (module.js:665:10)

回答1:

This was a bug in an interaction between the admin SDK and the regular node SDK for Firestore.

An update to @google-cloud/firestore 0.8.2 should fix this issue.

You can update your project with npm update to get this change.

回答2:

I encountered a similar error when implementing background functions to handle document update events. As the docs suggest, it is important to avoid infinite loops by checking that you do not inadvertently end up re-triggering the same function:

Any time you write to the same document that triggered a function, you are at risk of creating an infinite loop. Use caution and ensure that you safely exit the function when no change is needed

And also from here:

Caution: Be careful to avoid any situation in which the function's result actually retriggers the function, creating an infinite loop — for example, a function triggered by writes to a specific Cloud Firestore document that terminates by writing to that same path. Also make sure to write functions in an idempotent way, so that they produce the same result if they run multiple times for a single event.