AWS IoT Android application over MQTT throws MqttE

I am trying to use 'Authenticate using Cognito-Identity with Cognito user pool' in my Android application. My Cognito user pool authentication works well, when I run that separately and I had seen a JWTToken as well. When I run the the 'PubSub' sample application with Unauthenticated role, it worked as expected. When I integrate these two features in one application, the application threw following error.

W/System.err: MqttException (0) - java.io.IOException: Already connected
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:38)
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:664)
W/System.err:     at java.lang.Thread.run(Thread.java:761)
W/System.err: Caused by: java.io.IOException: Already connected
W/System.err:     at java.io.PipedOutputStream.connect(PipedOutputStream.java:100)
W/System.err:     at java.io.PipedInputStream.connect(PipedInputStream.java:195)
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketReceiver.<init>(WebSocketReceiver.java:42)
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketSecureNetworkModule.start(WebSocketSecureNetworkModule.java:78)
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:650)
W/System.err:   ... 1 more

I have been trying to resolve this issue since last Thursday and still stuck at the same place. Really No idea where should i check.!

I am adding my Authentication(Cognito user pool authentication) activity and Connect activity.

AmazonCognitoIdentityProviderClient identityProviderClient = new 
AmazonCognitoIdentityProviderClient(new AnonymousAWSCredentials(), new ClientConfiguration());
identityProviderClient.setRegion(Region.getRegion(Regions.US_WEST_2));
CognitoUserPool userPool = new CognitoUserPool(getApplicationContext(), "us-west-2_ghtcc6ho9", "4t0mk45hNso69dp2j4jvel5ghm", "1jmq0lhhq721oif9k6nug31c29i760vihua8hvrgu5umfr2a1vd7", identityProviderClient);
cogUser = userPool.getUser();
authenticationHandler = new AuthenticationHandler() {



        @Override
        public void onSuccess(CognitoUserSession userSession, CognitoDevice newDevice) {
            String ids = userSession.getIdToken().getJWTToken();
            Log.d("MyToken","session id___"+userSession.getIdToken().getExpiration()+"___"+userSession.getIdToken().getIssuedAt());
            Intent pubSub = new Intent(MainActivity.this, PubSubActivity.class);
            pubSub.putExtra("token",""+ids);
            startActivity(pubSub);
            //MainActivity.this.finish();

        }

        @Override
        public void getAuthenticationDetails(AuthenticationContinuation authenticationContinuation, String userId) {
            Log.d("MyToken","getAuthenticationDetails");
            AuthenticationDetails authenticationDetails = new AuthenticationDetails("shone", "172737", null);
            authenticationContinuation.setAuthenticationDetails(authenticationDetails);
            // Allow the sign-in to continue
            authenticationContinuation.continueTask();
        }

        @Override
        public void getMFACode(MultiFactorAuthenticationContinuation multiFactorAuthenticationContinuation) {
            Log.d("MyToken","getMFACode");
            multiFactorAuthenticationContinuation.continueTask();
        }

        @Override
        public void authenticationChallenge(ChallengeContinuation continuation) {
            Log.d("MyToken","authenticationChallenge"+continuation.getChallengeName());
            newPasswordContinuation.continueTask();
        }

        @Override
        public void onFailure(Exception exception) {
            exception.printStackTrace();
            Log.d("MyToken","onFailure");
        }
    };
     cogUser.getSessionInBackground(authenticationHandler);

When It reaches 'OnSuccess' I am launching my connect activity and passing my session token along with the Intent. Moving to the next activity

private static final String COGNITO_POOL_ID = "us-west-2:a153a090-508c-44c0-a9dd-efd450298c4b";
private static final Regions MY_REGION = Regions.US_WEST_2;
AWSIotMqttManager mqttManager;
String clientId;
AWSCredentials awsCredentials;
CognitoCachingCredentialsProvider credentialsProvider;
 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent intent = getIntent();
if(null == intent){
    Toast.makeText(getApplicationContext(), "Token is null", Toast.LENGTH_SHORT).show();
}else {
    token = intent.getStringExtra("token");
}
 clientId = UUID.randomUUID().toString();
    credentialsProvider = new CognitoCachingCredentialsProvider(
            getApplicationContext(), 
            COGNITO_POOL_ID, 
            MY_REGION 
    );
mqttManager = new AWSIotMqttManager(clientId, CUSTOMER_SPECIFIC_ENDPOINT);
 Map loginsMap = new HashMap();
    loginsMap.put("cognito-idp.us-west-2.amazonaws.com/us-west-2_ghtcc6ho9", token);
    credentialsProvider.setLogins(loginsMap);
    Log.d("SESSION_ID", ""+token);
    new Thread(new Runnable() {
        @Override
        public void run() {
            credentialsProvider.refresh();
            awsCredentials = credentialsProvider.getCredentials();
            Log.d("SESSION_ID B: ", ""+awsCredentials.getAWSAccessKeyId());
            Log.d("SESSION_ID C: ", ""+awsCredentials.getAWSSecretKey());
        }
    }).start();
}

 View.OnClickListener connectClick = new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        Log.d(LOG_TAG, "clientId = " + clientId);

        try {
            mqttManager.connect(credentialsProvider, new AWSIotMqttClientStatusCallback() {
                @Override
                public void onStatusChanged(final AWSIotMqttClientStatus status,
                        final Throwable throwable) {
                    Log.d(LOG_TAG, "Status = " + String.valueOf(status)+"______"+((null !=throwable)?throwable.getMessage():""));

                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            if (status == AWSIotMqttClientStatus.Connecting) {
                                tvStatus.setText("Connecting...");

                            } else if (status == AWSIotMqttClientStatus.Connected) {
                                tvStatus.setText("Connected");

                            } else if (status == AWSIotMqttClientStatus.Reconnecting) {
                                if (throwable != null) {
                                    Log.e(LOG_TAG, "Connection error.", throwable);
                                }
                                tvStatus.setText("Reconnecting");
                            } else if (status == AWSIotMqttClientStatus.ConnectionLost) {
                                if (throwable != null) {
                                    Log.e(LOG_TAG, "Connection error.", throwable);
                                    throwable.printStackTrace();
                                }
                                tvStatus.setText("Disconnected");
                            } else {
                                tvStatus.setText("Disconnected");

                            }
                        }
                    });
                }
            });
        } catch (final Exception e) {
            Log.e(LOG_TAG, "Connection error.", e);
        }
    }
};

What is wrong in my code? Why it throws exception when the MQTT connect is being invoked? Any help would be appreciated.

回答1:

I beat my head up with this almost a week.

Full course of action -> After succesfull login you will have a jwt token

String idToken = cognitoUserSession.getIdToken().getJWTToken();

put it into a map

Map<String, String> logins = new HashMap<String, String>(); 
//fill it with Cognito User token
logins.put("cognito-idp.<REGION>.amazonaws.com/<COGNITO_USER_POOL_ID>", idToken);

then use it to set in two places (not stated in any documentation!)

CognitoCachingCredentialsProvider credentialsProvider = new 
CognitoCachingCredentialsProvider(context, IDENTITY_POOL_ID, REGION);
credentialsProvider.setLogins(logins);

and

AmazonCognitoIdentity cognitoIdentity = new AmazonCognitoIdentityClient(credentialsProvider);
GetIdRequest getIdReq = new GetIdRequest();
getIdReq.setLogins(logins); //or if you have already set provider logins just use credentialsProvider.getLogins()
getIdReq.setIdentityPoolId(COGNITO_POOL_ID);
GetIdResult getIdRes = cognitoIdentity.getId(getIdReq);

after that you still nedd to make some call

AttachPrincipalPolicyRequest attachPolicyReq = new AttachPrincipalPolicyRequest(); //in docs it called AttachPolicyRequest but it`s wrong
attachPolicyReq.setPolicyName("allAllowed"); //name of your IOTAWS policy
attachPolicyReq.setPrincipal(getIdRes.getIdentityId());
new AWSIotClient(credentialsProvider).attachPrincipalPolicy(attachPolicyReq);

and only after that you can enable connect button and continue like that

mqttManager.connect(credentialsProvider, new AWSIotMqttClientStatusCallback() {

Really for this small piece of code i spent a lot of time...

回答2:

When a client connected to broker it has a unique client ID. If clients tried to connect with same client id then this error occur. Use different client IDs like foo1, foo2, foo3, etc.