Queued mutations are lost on network exception

[chorniyn]

Description
It turns out that AppSync on Android "looses" the mutations after the network exception.

To Reproduce

1. A couple of mutations were successfully queued while device had no connection to any network
2. Device was connected to the wifi network with no internet connection
3. AppSync SDK detected the connection and tried to synchronize the mutations and that expectedly failed
4. Wifi was turned off and mobile internet (cellular connection) was turned on

Result: none of the queued (and failed on step 3) mutations were executed after that, the data was lost.

Expected behavior

1. Events are stored in the way they are queued. If mutations A, B and C are queued and mutation A fails to be synced, mutation B synchronization should not even start (but it did actually)
2. Failed mutations should not be lost (they have to be retried)

Logs

Mutation failure (step 3)

2018-12-14 15:05:16.939 5692-18037/com.ehawk.ehawktracker E/SaveEventOperations_AS: Mutation CreateEvent failed, op id: 49d603320ce837d012619193ffb100e60bb4a6fd0e66345e8cd2341ac729b185, input: {id=afe67eb2-e0ed-4064-bfdd-afd3b09a852b, caseId=5678-chorniy-11635e63-5674-4018-a08d-aad42fd9f02e, offenderId=5678-chorniy-b49b6766-9da0-4d03-bea5-72e9188a8e3d, time=1.544792706797E9, type=ServiceStateChange, agencyId=agency, serviceName=LocationService, enabledProviders=["GPS","NETWORK"]}
    com.apollographql.apollo.exception.ApolloNetworkException: Failed to execute http call
        at com.apollographql.apollo.internal.interceptor.ApolloServerInterceptor$1$1.onFailure(ApolloServerInterceptor.java:105)
        at okhttp3.RealCall$AsyncCall.execute(RealCall.java:148)
        at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:760)
     Caused by: java.net.SocketTimeoutException: timeout
        at okhttp3.internal.http2.Http2Stream$StreamTimeout.newTimeoutException(Http2Stream.java:593)
        at okhttp3.internal.http2.Http2Stream$StreamTimeout.exitAndThrowIfTimedOut(Http2Stream.java:601)
        at okhttp3.internal.http2.Http2Stream.takeResponseHeaders(Http2Stream.java:146)
        at okhttp3.internal.http2.Http2Codec.readResponseHeaders(Http2Codec.java:120)
        at okhttp3.internal.http.CallServerInterceptor.intercept(CallServerInterceptor.java:75)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:45)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:120)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at com.amazonaws.mobileconnectors.appsync.sigv4.AppSyncSigV4SignerInterceptor.intercept(AppSyncSigV4SignerInterceptor.java:181)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at com.amazonaws.mobileconnectors.appsync.retry.RetryInterceptor.intercept(RetryInterceptor.java:50)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:185)
        at okhttp3.RealCall$AsyncCall.execute(RealCall.java:135)
        at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
        at java.lang.Thread.run(Thread.java:760) 

Environment:

• AppSync SDK was built from branch https://github.com/awslabs/aws-mobile-appsync-sdk-android/tree/bug-fixes, this commit 71c091c

Device Information:

• Device: Xiaomi MI5s
• Android Version: 7.0

[scb01]

@nchorniy

Thank you for reporting this issue. I am working on a solution for this and am targeting it to be included in the next version.

[scb01]

@nchorniy

Version 2.7.1 of the SDK contains network error handling and queuing logic to address the issue that you reported. Please upgrade to this version and let us know how you fare.

[chorniyn]

@cbommas thanks, it seems the issue is fully fixed. Both things work :

• data was not lost
• and it was stored in the correct order

The testing was conducted on another device this time: Samsung J7 (2016) running on Android 7. Testing scenario was the same.

[frankmuellr]

Hello @nchorniy,

that's great news! Thank you for testing and providing a detailed update. I am going ahead and closing this issue. If you encounter any other problems, please open a new issue.