Firestore JS on Android fails to recover connection when returning from background

[mydoal]

[REQUIRED] Describe your environment

• Operating System version: Android 7.1.1
• Android SDK: 26.0.2
• Browser version: Chrome
• Firebase SDK version: 4.12.1
• Firebase Product: Firestore
• Ionic version: 3.19.1
• Ionic Angular version: 3.9.2
• Cordova Android: 6.4.0
• AngularFire version: 5.0.0-rc.5-next

[REQUIRED] Describe the problem

Cordova Ionic app running Firestore JS fails to recover connection when returning form background.
The console shows retries of attempts to re-establish connection.
Only restarting the app resolves the problem.

This problem started a week ago after starting testing app on Android 7.1.1.
The test used to run on Android 6.0 without any problems with the same version of all packages.

Steps to reproduce:

Open Cordova Android app running Angular+Firebase and do email authorization
Move app to the background (pressing the Android home button)
Wait a few minuts
Reopen the app (we are still logged in)
Open an angular page that uses Firestore api to retrieve a document

e.g.:

firebase.firestore().collection("profiles").doc(profileId).get()

The console shows multiple errors:

 {code: "auth/network-request-failed", message: "A network error (such as timeout, interrupted connection or unreachable host) has occurred."}

vendor.js:1 ERROR Error: Uncaught (in promise): FirebaseError: [code=aborted]: Failed to get document because the client is offline.
FirebaseError: Failed to get document because the client is offline.

ERROR Error: Uncaught (in promise): FirebaseError: [code=aborted]: Failed to get document because the client is offline.
FirebaseError: Failed to get document because the client is offline.

And fails to re-establish connection to Firestore:

vendor.js:1 ERROR nn
(anonymous) @ vendor.js:1
vendor.js:1 ERROR nn
(anonymous) @ vendor.js:1
vendor.js:1 ERROR nn
(anonymous) @ vendor.js:1
vendor.js:1 ERROR nn
(anonymous) @ vendor.js:1
vendor.js:1 ERROR nn

When turning on the log at debug level:

firebase.firestore().setLogLevel('debug')

We get some more information:

vendor.js:1 [2018-07-28T09:36:40.634Z]  @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unknown]: Fetching auth token failed: A network error (such as timeout, interrupted connection or unreachable host) has occurred.
vendor.js:1 [2018-07-28T09:36:40.636Z]  @firebase/firestore: Firestore (4.10.1) [ExponentialBackoff]: Backing off for 2212.7402860971715 ms (base delay: 1500 ms)
...
vendor.js:1 [2018-07-28T09:37:43.017Z]  @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unknown]: Fetching auth token failed: A network error (such as timeout, interrupted connection or unreachable host) has occurred.
vendor.js:1 [2018-07-28T09:37:43.018Z]  @firebase/firestore: Firestore (4.10.1) [ExponentialBackoff]: Backing off for 1865.6266004521462 ms (base delay: 2250 ms)
vendor.js:1 ERROR nn
...
vendor.js:1 [2018-07-28T09:39:52.641Z]  @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unknown]: Fetching auth token failed: A network error (such as timeout, interrupted connection or unreachable host) has occurred.
vendor.js:1 [2018-07-28T09:39:52.644Z]  @firebase/firestore: Firestore (4.10.1) [ExponentialBackoff]: Backing off for 3589.0911531043184 ms (base delay: 5062.5 ms)
vendor.js:1 ERROR nn
...
vendor.js:1 [2018-07-28T09:43:24.775Z]  @firebase/firestore: Firestore (4.10.1) [Connection]: Creating WebChannel: https://firestore.googleapis.com/google.firestore.v1beta1.Firestore/Listen/channel [object Object]
vendor.js:1 [2018-07-28T09:43:25.632Z]  @firebase/firestore: Firestore (4.10.1) [Connection]: Opening WebChannel transport.
vendor.js:1 [2018-07-28T09:43:25.634Z]  @firebase/firestore: Firestore (4.10.1) [Connection]: WebChannel sending: {"database":"projects/xxx/(default)","addTarget":{"documents":{"documents":["projects/xxx/(default)/documents/profilesBadges/jRpVDzeqilsxbFRrCLBX"]},"targetId":16,"resumeToken":"CgkI0f6y0r7B3AI="}}
vendor.js:1 [2018-07-28T09:44:12.635Z]  @firebase/firestore: Firestore (4.10.1) [Connection]: WebChannel transport errored: Te
vendor.js:1 [2018-07-28T09:44:12.635Z]  @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unavailable]: The operation could not be completed
...
vendor.js:1 [2018-07-28T09:56:15.635Z]  @firebase/firestore: Firestore (4.10.1) [Connection]: WebChannel transport errored: Te
vendor.js:1 [2018-07-28T09:56:15.636Z]  @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unavailable]: The operation could not be completed
vendor.js:1 [2018-07-28T09:56:15.637Z]  @firebase/firestore: Firestore (4.10.1) [ExponentialBackoff]: Backing off for 64064.01037516744 ms (base delay: 60000 ms)
www.google.com/images/cleardot.gif?zx=dzwv0lyag6eu:1 Failed to load resource: net::ERR_CONNECTION_TIMED_OUT
...

After restarting the app everything continues to work,

** While the console shows the errors, the app manages to make other RETS api calls via the network - there is a working internet connection **

[mydoal]

Update:

1. Adding the SHA-1 key to Firebase Console does not help.

2. The problem has gotten worse:

When reloading the JS code, you cannot login to Firebase anymore:

{code: "auth/network-request-failed", message: "A network error (such as timeout, interrupted connection or unreachable host) has occurred."}

Only restarting the Android app running the JS in a webview manages to reset the problem.

[mydoal]

Update:

This issue is not happening on Android 6.0.
Started happening on Android 7.1.1
Can this be related to the Doze and Background Optimizations introduced in Android 7.0?

https://developer.android.com/about/versions/nougat/android-7.0-changes

[wilhuff]

Unfortunately, this specific problem has nothing to do with Firestore. Firestore isn't even trying to connect: it's failing to get a token from Firebase Auth and not even trying to connect to its own backend:

vendor.js:1 [2018-07-28T09:36:40.634Z] @firebase/firestore: Firestore (4.10.1) [PersistentStream]: close with error: FirebaseError: [code=unknown]: Fetching auth token failed: A network error (such as timeout, interrupted connection or unreachable host) has occurred.

Firebase Auth, in turn is just doing basic XHRs to its backend. I strongly suspect something's up with Cordova + Android 7.1.1 but I don't know enough about it.

How are you signing in (if at all)?

[mydoal]

Thanks @wilhuff for your reply.
I am signing in using firebase.auth.Auth.signInWithEmailAndPassword via AngularFire2.

** The network is connected. I am able to make a rest api call in Angular from the same page while Firebase insists there in no connection **

• The same apk works perfectly on Android 6.0.
• If I turn Wi-Fi on, or the data on and off then Firebase manages to connect.
• If I reload the Angular app, Firebase auth will fail to login stating it cannot connect, you have to close and restart the Android app.

[wti806]

@mydoal I cannot replicate the issue using android@7.1.1 and cordova@6.4.0. I tried to signInWithEmailAndPassword and pressed the home button. They reopened the app to make other rpc calls. It works fine for me. I did test on a emulator though. Does this issue only occur on real device?

[mydoal]

Thanks for your reply @wti806 .
The problem occurs on a new LG Q6 Android 7.1.1 device.
Same apk has been working fine on LG G4 Android 6 device for the past months.
The problem occurs after the app is in the background for a few minutes (sometimes up to an hour) and then reopened. It seems as if Firestore is not aware that the network is back (probably after doze or standby). Network connection is definitely working. While Firestore keeps trying to connect and fail, other non Firebase Rest API calls are successful.

[wti806]

@mydoal Can you replicate the issue on a 7.1.1 emulator before you deploy it to real device? The error is thrown from Auth component. I did try to move the app to background and then re-open. Didn't wait for an hour though. After that, I called a few Auth APIs to trigger REST calls and it works fine.

[mydoal]

@wti806 it works for me also if I wait for a few minutes. The device does not go into doze / standby mode in that timeframe. Only after > 30 min this happens. I will run it in an emulator and update here. I am not sure the emulator really emulates the doze / standby of a real device though.