Add retries to demos in case of a failure. (#435)

FreeRTOS-Plus/Demo/AWS/Device_Defender_Windows_Simulator/Device_Defender_Demo/DemoTasks/DefenderDemoExample.c

@@ -107,6 +107,22 @@
  */
 #define DEFENDER_RESPONSE_REPORT_ID_FIELD_LENGTH    ( sizeof( DEFENDER_RESPONSE_REPORT_ID_FIELD ) - 1 )
 
+/**
+ * @brief The maximum number of times to run the loop in this demo.
+ *
+ * @note The demo loop is attempted to re-run only if it fails in an iteration.
+ * Once the demo loop succeeds in an iteration, the demo exits successfully.
+ */
+#ifndef DEFENDER_MAX_DEMO_LOOP_COUNT
+    #define DEFENDER_MAX_DEMO_LOOP_COUNT    ( 3 )
+#endif
+
+/**
+ * @brief Time in ticks to wait between retries of the demo loop if
+ * demo loop fails.
+ */
+#define DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS    ( pdMS_TO_TICKS( 5000U ) )
+
 /**
  * @brief Status values of the device defender report.
  */
@@ -633,6 +649,7 @@ void prvDefenderDemoTask( void * pvParameters )
     bool xStatus = false;
     BaseType_t xExitStatus = EXIT_FAILURE;
     uint32_t ulReportLength = 0UL, i, ulMqttSessionEstablished = 0UL;
+    UBaseType_t uxDemoRunCount = 0UL;
 
     /* Remove compiler warnings about unused parameters. */
     ( void ) pvParameters;
@@ -643,6 +660,11 @@ void prvDefenderDemoTask( void * pvParameters )
     /* Start with report not received. */
     xReportStatus = ReportStatusNotReceived;
 
+    /* This demo runs a single loop unless there are failures in the demo execution.
+     * In case of failures in the demo execution, demo loop will be retried for up to
+     * DEFENDER_MAX_DEMO_LOOP_COUNT times. */
+    do
+    {
         /* Set a report Id to be used.
          *
          * !!!NOTE!!!
@@ -789,7 +811,7 @@ void prvDefenderDemoTask( void * pvParameters )
                 }
 
                 /* Wait for sometime between consecutive executions of ProcessLoop. */
-            vTaskDelay( 1000 / portTICK_PERIOD_MS );
+                vTaskDelay( pdMS_TO_TICKS( 1000U ) );
             }
         }
 
@@ -820,11 +842,38 @@ void prvDefenderDemoTask( void * pvParameters )
                                              &xNetworkContext );
         }
 
-    /****************************** Finish. ******************************/
-
         if( ( xStatus == true ) && ( xReportStatus == ReportStatusAccepted ) )
         {
             xExitStatus = EXIT_SUCCESS;
+        }
+
+        /*********************** Retry in case of failure. ************************/
+
+        /* Increment the demo run count. */
+        uxDemoRunCount++;
+
+        if( xExitStatus == EXIT_SUCCESS )
+        {
+            LogInfo( ( "Demo iteration %lu is successful.", uxDemoRunCount ) );
+        }
+        /* Attempt to retry a failed iteration of demo for up to #DEFENDER_MAX_DEMO_LOOP_COUNT times. */
+        else if( uxDemoRunCount < DEFENDER_MAX_DEMO_LOOP_COUNT )
+        {
+            LogWarn( ( "Demo iteration %lu failed. Retrying...", uxDemoRunCount ) );
+            vTaskDelay( DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS );
+        }
+        /* Failed all #DEFENDER_MAX_DEMO_LOOP_COUNT demo iterations. */
+        else
+        {
+            LogError( ( "All %d demo iterations failed.", DEFENDER_MAX_DEMO_LOOP_COUNT ) );
+            break;
+        }
+    } while( xExitStatus != EXIT_SUCCESS );
+
+    /****************************** Finish. ******************************/
+
+    if( xExitStatus == EXIT_SUCCESS )
+    {
         LogInfo( ( "Demo completed successfully." ) );
     }
     else

FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c

@@ -148,6 +148,55 @@
  */
 #define SHADOW_REPORTED_JSON_LENGTH    ( sizeof( SHADOW_REPORTED_JSON ) - 3 )
 
+/**
+ * @brief The maximum number of times to run the loop in this demo.
+ *
+ * @note The demo loop is attempted to re-run only if it fails in an iteration.
+ * Once the demo loop succeeds in an iteration, the demo exits successfully.
+ */
+#ifndef SHADOW_MAX_DEMO_LOOP_COUNT
+    #define SHADOW_MAX_DEMO_LOOP_COUNT    ( 3 )
+#endif
+
+/**
+ * @brief Time in ticks to wait between retries of the demo loop if
+ * demo loop fails.
+ */
+#define DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS       ( pdMS_TO_TICKS( 5000U ) )
+
+/**
+ * @brief The maximum number of times to call MQTT_ProcessLoop() when waiting
+ * for a response for Shadow delete operation.
+ */
+#define MQTT_PROCESS_LOOP_DELETE_RESPONSE_COUNT_MAX     ( 30U )
+
+/**
+ * @brief Timeout for MQTT_ProcessLoop in milliseconds.
+ */
+#define MQTT_PROCESS_LOOP_TIMEOUT_MS                    ( 700U )
+
+/**
+ * @brief JSON key for response code that indicates the type of error in
+ * the error document received on topic `/delete/rejected`.
+ */
+#define SHADOW_DELETE_REJECTED_ERROR_CODE_KEY           "code"
+
+/**
+ * @brief Length of #SHADOW_DELETE_REJECTED_ERROR_CODE_KEY.
+ */
+#define SHADOW_DELETE_REJECTED_ERROR_CODE_KEY_LENGTH    ( ( uint16_t ) ( sizeof( SHADOW_DELETE_REJECTED_ERROR_CODE_KEY ) - 1 ) )
+
+/**
+ * @brief Error response code sent from AWS IoT Shadow service when an attempt
+ * is made to delete a Shadow document that doesn't exist.
+ */
+#define SHADOW_NO_SHADOW_EXISTS_ERROR_CODE              "404"
+
+/**
+ * @brief Length of #SHADOW_NO_SHADOW_EXISTS_ERROR_CODE.
+ */
+#define SHADOW_NO_SHADOW_EXISTS_ERROR_CODE_LENGTH       ( ( uint16_t ) ( sizeof( SHADOW_NO_SHADOW_EXISTS_ERROR_CODE ) - 1 ) )
+
 /*------------- Demo configurations -------------------------*/
 
 #ifndef democonfigTHING_NAME
@@ -225,6 +274,24 @@ static BaseType_t xUpdateDeltaReturn = pdPASS;
  */
 static BaseType_t xUpdateAcceptedReturn = pdPASS;
 
+/**
+ * @brief Status of the response of Shadow delete operation from AWS IoT
+ * message broker.
+ */
+static BaseType_t xDeleteResponseReceived = pdFALSE;
+
+/**
+ * @brief Status of the Shadow delete operation.
+ *
+ * The Shadow delete status will be updated by the incoming publishes on the
+ * MQTT topics for delete acknowledgement from AWS IoT message broker
+ * (accepted/rejected). Shadow document is considered to be deleted if an
+ * incoming publish is received on `/delete/accepted` topic or an incoming
+ * publish is received on `/delete/rejected` topic with error code 404. Code 404
+ * indicates that the Shadow document does not exist for the Thing yet.
+ */
+static BaseType_t xShadowDeleted = pdFALSE;
+
 /*-----------------------------------------------------------*/
 
 /**
@@ -271,6 +338,126 @@ static void prvUpdateAcceptedHandler( MQTTPublishInfo_t * pxPublishInfo );
  */
 static void prvShadowDemoTask( void * pvParameters );
 
+/**
+ * @brief Process payload from `/delete/rejected` topic.
+ *
+ * This handler examines the rejected message to look for the reject reason code.
+ * If the reject reason code is `404`, an attempt was made to delete a shadow
+ * document which was not present yet. This is considered to be success for this
+ * demo application.
+ *
+ * @param[in] pxPublishInfo Deserialized publish info pointer for the incoming
+ * packet.
+ */
+static void prvDeleteRejectedHandler( MQTTPublishInfo_t * pxPublishInfo );
+
+/**
+ * @brief Helper function to wait for a response for Shadow delete operation.
+ *
+ * @param[in] pxMQTTContext MQTT context pointer.
+ *
+ * @return pdPASS if successfully received a response for Shadow delete
+ * operation; pdFAIL otherwise.
+ */
+static BaseType_t prvWaitForDeleteResponse( MQTTContext_t * pxMQTTContext );
+
+/*-----------------------------------------------------------*/
+
+static BaseType_t prvWaitForDeleteResponse( MQTTContext_t * pxMQTTContext )
+{
+    uint8_t ucCount = 0U;
+    MQTTStatus_t xMQTTStatus = MQTTSuccess;
+    BaseType_t xReturnStatus = pdPASS;
+
+    configASSERT( pxMQTTContext != NULL );
+
+    while( ( xDeleteResponseReceived != pdTRUE ) &&
+           ( ucCount++ < MQTT_PROCESS_LOOP_DELETE_RESPONSE_COUNT_MAX ) &&
+           ( xMQTTStatus == MQTTSuccess ) )
+    {
+        /* Event callback will set #xDeleteResponseReceived when receiving an
+         * incoming publish on either `/delete/accepted` or `/delete/rejected`
+         * Shadow topics. */
+        xMQTTStatus = MQTT_ProcessLoop( pxMQTTContext, MQTT_PROCESS_LOOP_TIMEOUT_MS );
+    }
+
+    if( ( xMQTTStatus != MQTTSuccess ) || ( xDeleteResponseReceived != pdTRUE ) )
+    {
+        LogError( ( "MQTT_ProcessLoop failed to receive a response for Shadow delete operation:"
+                    " LoopDuration=%u, MQTT Status=%s.",
+                    ( MQTT_PROCESS_LOOP_TIMEOUT_MS * ucCount ),
+                    MQTT_Status_strerror( xMQTTStatus ) ) );
+        xReturnStatus = pdFAIL;
+    }
+
+    return xReturnStatus;
+}
+
+/*-----------------------------------------------------------*/
+
+static void prvDeleteRejectedHandler( MQTTPublishInfo_t * pxPublishInfo )
+{
+    JSONStatus_t result = JSONSuccess;
+    char * pcOutValue = NULL;
+    uint32_t ulOutValueLength = 0UL;
+
+    configASSERT( pxPublishInfo != NULL );
+    configASSERT( pxPublishInfo->pPayload != NULL );
+
+    LogInfo( ( "/delete/rejected json payload:%s.", ( const char * ) pxPublishInfo->pPayload ) );
+
+    /* The payload will look similar to this:
+     * {
+     *    "code": error-code,
+     *    "message": "error-message",
+     *    "timestamp": timestamp,
+     *    "clientToken": "token"
+     * }
+     */
+
+    /* Make sure the payload is a valid json document. */
+    result = JSON_Validate( pxPublishInfo->pPayload,
+                            pxPublishInfo->payloadLength );
+
+    if( result == JSONSuccess )
+    {
+        /* Then we start to get the version value by JSON keyword "version". */
+        result = JSON_SearchConst( pxPublishInfo->pPayload,
+                                   pxPublishInfo->payloadLength,
+                                   SHADOW_DELETE_REJECTED_ERROR_CODE_KEY,
+                                   SHADOW_DELETE_REJECTED_ERROR_CODE_KEY_LENGTH,
+                                   &pcOutValue,
+                                   ( size_t * ) &ulOutValueLength,
+                                   NULL );
+    }
+    else
+    {
+        LogError( ( "The json document is invalid!!" ) );
+    }
+
+    if( result == JSONSuccess )
+    {
+        LogInfo( ( "Error code is: %.*s.",
+                   ulOutValueLength,
+                   pcOutValue ) );
+
+        /* Check if error code is `404`. An error code `404` indicates that an
+         * attempt was made to delete a Shadow document that didn't exist. */
+        if( ulOutValueLength == SHADOW_NO_SHADOW_EXISTS_ERROR_CODE_LENGTH )
+        {
+            if( strncmp( pcOutValue, SHADOW_NO_SHADOW_EXISTS_ERROR_CODE,
+                         SHADOW_NO_SHADOW_EXISTS_ERROR_CODE_LENGTH ) == 0 )
+            {
+                xShadowDeleted = pdTRUE;
+            }
+        }
+    }
+    else
+    {
+        LogError( ( "No error code in json document!!" ) );
+    }
+}
+
 /*-----------------------------------------------------------*/
 
 static void prvUpdateDeltaHandler( MQTTPublishInfo_t * pxPublishInfo )
@@ -536,6 +723,18 @@ static void prvEventCallback( MQTTContext_t * pxMqttContext,
             {
                 LogInfo( ( "/update/rejected json payload:%s.", ( const char * ) pxDeserializedInfo->pPublishInfo->pPayload ) );
             }
+            else if( messageType == ShadowMessageTypeDeleteAccepted )
+            {
+                LogInfo( ( "Received an MQTT incoming publish on /delete/accepted topic." ) );
+                xShadowDeleted = pdTRUE;
+                xDeleteResponseReceived = pdTRUE;
+            }
+            else if( messageType == ShadowMessageTypeDeleteRejected )
+            {
+                /* Handler function to process payload. */
+                prvDeleteRejectedHandler( pxDeserializedInfo->pPublishInfo );
+                xDeleteResponseReceived = pdTRUE;
+            }
             else
             {
                 LogInfo( ( "Other message type:%d !!", messageType ) );
@@ -593,7 +792,8 @@ void vStartShadowDemo( void )
  */
 void prvShadowDemoTask( void * pvParameters )
 {
-    BaseType_t demoStatus = pdPASS;
+    BaseType_t xDemoStatus = pdPASS;
+    UBaseType_t uxDemoRunCount = 0UL;
 
     /* A buffer containing the update document. It has static duration to prevent
      * it from being placed on the call stack. */
@@ -607,50 +807,113 @@ void prvShadowDemoTask( void * pvParameters )
 
     /****************************** Connect. ******************************/
 
-    demoStatus = xEstablishMqttSession( &xMqttContext,
+    /* This demo runs a single loop unless there are failures in the demo execution.
+     * In case of failures in the demo execution, demo loop will be retried for up to
+     * SHADOW_MAX_DEMO_LOOP_COUNT times. */
+    do
+    {
+        /****************************** Connect. ******************************/
+
+        xDemoStatus = xEstablishMqttSession( &xMqttContext,
                                              &xNetworkContext,
                                              &xBuffer,
                                              prvEventCallback );
 
-    if( demoStatus == pdFAIL )
+        if( xDemoStatus == pdFAIL )
         {
             /* Log error to indicate connection failure. */
             LogError( ( "Failed to connect to MQTT broker." ) );
         }
 
-    if( demoStatus == pdPASS )
+        /**************** Attempt to delete Shadow document. ******************/
+
+        if( xDemoStatus == pdPASS )
         {
-        /* Try to delete any Shadow document in the cloud. This is done to
+            /* Reset the shadow delete status flags. */
-         * ensure possbile previous Shadow documents do not affect the state
+            xDeleteResponseReceived = pdFALSE;
-         * expected in the current demo. */
+            xShadowDeleted = pdFALSE;
-        demoStatus = xPublishToTopic( &xMqttContext,
+
+            /* First of all, try to delete any Shadow document in the cloud.
+             * Try to subscribe to `/delete/accepted` and `/delete/rejected` topics. */
+            xDemoStatus = xSubscribeToTopic( &xMqttContext,
+                                             SHADOW_TOPIC_STRING_DELETE_ACCEPTED( democonfigTHING_NAME ),
+                                             SHADOW_TOPIC_LENGTH_DELETE_ACCEPTED( THING_NAME_LENGTH ) );
+        }
+
+        if( xDemoStatus == pdPASS )
+        {
+            /* Try to subscribe to `/delete/rejected` topic. */
+            xDemoStatus = xSubscribeToTopic( &xMqttContext,
+                                             SHADOW_TOPIC_STRING_DELETE_REJECTED( democonfigTHING_NAME ),
+                                             SHADOW_TOPIC_LENGTH_DELETE_REJECTED( THING_NAME_LENGTH ) );
+        }
+
+        if( xDemoStatus == pdPASS )
+        {
+            /* Publish to Shadow `delete` topic to attempt to delete the
+             * Shadow document if exists. */
+            xDemoStatus = xPublishToTopic( &xMqttContext,
                                            SHADOW_TOPIC_STRING_DELETE( democonfigTHING_NAME ),
                                            SHADOW_TOPIC_LENGTH_DELETE( THING_NAME_LENGTH ),
                                            pcUpdateDocument,
                                            0U );
         }
 
+        /* Wait for an incoming publish on `/delete/accepted` or `/delete/rejected`
+         * topics, if not already received a publish. */
+        if( ( xDemoStatus == pdPASS ) && ( xDeleteResponseReceived != pdTRUE ) )
+        {
+            xDemoStatus = prvWaitForDeleteResponse( &xMqttContext );
+        }
+
+        /* Unsubscribe from the `/delete/accepted` and 'delete/rejected` topics.*/
+        if( xDemoStatus == pdPASS )
+        {
+            xDemoStatus = xUnsubscribeFromTopic( &xMqttContext,
+                                                 SHADOW_TOPIC_STRING_DELETE_ACCEPTED( democonfigTHING_NAME ),
+                                                 SHADOW_TOPIC_LENGTH_DELETE_ACCEPTED( THING_NAME_LENGTH ) );
+        }
+
+        if( xDemoStatus == pdPASS )
+        {
+            xDemoStatus = xUnsubscribeFromTopic( &xMqttContext,
+                                                 SHADOW_TOPIC_STRING_DELETE_REJECTED( democonfigTHING_NAME ),
+                                                 SHADOW_TOPIC_LENGTH_DELETE_REJECTED( THING_NAME_LENGTH ) );
+        }
+
+        /* Check if Shadow document delete was successful. A delete can be
+         * successful in cases listed below.
+         *  1. If an incoming publish is received on `/delete/accepted` topic.
+         *  2. If an incoming publish is received on `/delete/rejected` topic
+         *     with error code 404. This indicates that a Shadow document was
+         *     not present for the Thing. */
+        if( xShadowDeleted == pdFALSE )
+        {
+            LogError( ( "Shadow delete operation failed." ) );
+            xDemoStatus = pdFAIL;
+        }
+
         /********************* Subscribe to Shadow topics. ************************/
 
         /* Then try to subscribe the Shadow topics. */
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
-        demoStatus = xSubscribeToTopic( &xMqttContext,
+            xDemoStatus = xSubscribeToTopic( &xMqttContext,
                                              SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ),
                                              SHADOW_TOPIC_LENGTH_UPDATE_DELTA( THING_NAME_LENGTH ) );
         }
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
-        demoStatus = xSubscribeToTopic( &xMqttContext,
+            xDemoStatus = xSubscribeToTopic( &xMqttContext,
                                              SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ),
                                              SHADOW_TOPIC_LENGTH_UPDATE_ACCEPTED( THING_NAME_LENGTH ) );
         }
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
-        demoStatus = xSubscribeToTopic( &xMqttContext,
+            xDemoStatus = xSubscribeToTopic( &xMqttContext,
                                              SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ),
                                              SHADOW_TOPIC_LENGTH_UPDATE_REJECTED( THING_NAME_LENGTH ) );
         }
@@ -689,7 +952,7 @@ void prvShadowDemoTask( void * pvParameters )
          * the device itself. But for the purpose of making this demo self-contained,
          * we publish one here so that we can receive a delta message later.
          */
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
             /* Desired power on state . */
             LogInfo( ( "Send desired power state with 1." ) );
@@ -704,14 +967,14 @@ void prvShadowDemoTask( void * pvParameters )
                       ( int ) 1,
                       ( long unsigned ) ( xTaskGetTickCount() % 1000000 ) );
 
-        demoStatus = xPublishToTopic( &xMqttContext,
+            xDemoStatus = xPublishToTopic( &xMqttContext,
                                            SHADOW_TOPIC_STRING_UPDATE( democonfigTHING_NAME ),
                                            SHADOW_TOPIC_LENGTH_UPDATE( THING_NAME_LENGTH ),
                                            pcUpdateDocument,
                                            ( SHADOW_DESIRED_JSON_LENGTH + 1 ) );
         }
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
             /* Note that PublishToTopic already called MQTT_ProcessLoop,
              * therefore responses may have been received and the prvEventCallback
@@ -737,7 +1000,7 @@ void prvShadowDemoTask( void * pvParameters )
                           ( int ) ulCurrentPowerOnState,
                           ( long unsigned ) ulClientToken );
 
-            demoStatus = xPublishToTopic( &xMqttContext,
+                xDemoStatus = xPublishToTopic( &xMqttContext,
                                                SHADOW_TOPIC_STRING_UPDATE( democonfigTHING_NAME ),
                                                SHADOW_TOPIC_LENGTH_UPDATE( THING_NAME_LENGTH ),
                                                pcUpdateDocument,
@@ -751,41 +1014,41 @@ void prvShadowDemoTask( void * pvParameters )
 
         /****************** Unsubscribe from Shadow topics. *******************/
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
             LogInfo( ( "Start to unsubscribe shadow topics and disconnect from MQTT. \r\n" ) );
 
-        demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+            xDemoStatus = xUnsubscribeFromTopic( &xMqttContext,
                                                  SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ),
                                                  SHADOW_TOPIC_LENGTH_UPDATE_DELTA( THING_NAME_LENGTH ) );
 
-        if( demoStatus != pdPASS )
+            if( xDemoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
                             SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ) ) );
             }
         }
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
-        demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+            xDemoStatus = xUnsubscribeFromTopic( &xMqttContext,
                                                  SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ),
                                                  SHADOW_TOPIC_LENGTH_UPDATE_ACCEPTED( THING_NAME_LENGTH ) );
 
-        if( demoStatus != pdPASS )
+            if( xDemoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
                             SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ) ) );
             }
         }
 
-    if( demoStatus == pdPASS )
+        if( xDemoStatus == pdPASS )
         {
-        demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+            xDemoStatus = xUnsubscribeFromTopic( &xMqttContext,
                                                  SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ),
                                                  SHADOW_TOPIC_LENGTH_UPDATE_REJECTED( THING_NAME_LENGTH ) );
 
-        if( demoStatus != pdPASS )
+            if( xDemoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
                             SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ) ) );
@@ -795,7 +1058,7 @@ void prvShadowDemoTask( void * pvParameters )
         /****************************** Disconnect. *******************************/
 
         /* The MQTT session is always disconnected, even if there were prior failures. */
-    demoStatus = xDisconnectMqttSession( &xMqttContext, &xNetworkContext );
+        xDemoStatus = xDisconnectMqttSession( &xMqttContext, &xNetworkContext );
 
         /* This demo performs only Device Shadow operations. If matching the Shadow
          * MQTT topic fails or there are failure in parsing the received JSON document,
@@ -805,7 +1068,30 @@ void prvShadowDemoTask( void * pvParameters )
             LogError( ( "Callback function failed." ) );
         }
 
-    if( demoStatus == pdPASS )
+        /*********************** Retry in case of failure. ************************/
+
+        /* Increment the demo run count. */
+        uxDemoRunCount++;
+
+        if( xDemoStatus == pdPASS )
+        {
+            LogInfo( ( "Demo iteration %lu is successful.", uxDemoRunCount ) );
+        }
+        /* Attempt to retry a failed iteration of demo for up to #SHADOW_MAX_DEMO_LOOP_COUNT times. */
+        else if( uxDemoRunCount < SHADOW_MAX_DEMO_LOOP_COUNT )
+        {
+            LogWarn( ( "Demo iteration %lu failed. Retrying...", uxDemoRunCount ) );
+            vTaskDelay( DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS );
+        }
+        /* Failed all #SHADOW_MAX_DEMO_LOOP_COUNT demo iterations. */
+        else
+        {
+            LogError( ( "All %d demo iterations failed.", SHADOW_MAX_DEMO_LOOP_COUNT ) );
+            break;
+        }
+    } while( xDemoStatus != pdPASS );
+
+    if( xDemoStatus == pdPASS )
     {
         LogInfo( ( "Demo completed successfully." ) );
     }

FreeRTOS-Plus/Demo/AWS/Jobs_Windows_Simulator/Jobs_Demo/DemoTasks/JobsDemoExample.c

@@ -208,6 +208,22 @@
  */
 #define MAKE_STATUS_REPORT( x )    "{\"status\":\"" x "\"}"
 
+/**
+ * @brief The maximum number of times to run the loop in this demo.
+ *
+ * @note The demo loop is attempted to re-run only if it fails in an iteration.
+ * Once the demo loop succeeds in an iteration, the demo exits successfully.
+ */
+#ifndef JOBS_MAX_DEMO_LOOP_COUNT
+    #define JOBS_MAX_DEMO_LOOP_COUNT    ( 3 )
+#endif
+
+/**
+ * @brief Time in ticks to wait between retries of the demo loop if
+ * demo loop fails.
+ */
+#define DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS    ( pdMS_TO_TICKS( 5000U ) )
+
 /*-----------------------------------------------------------*/
 
 /**
@@ -735,6 +751,8 @@ void vStartJobsDemo( void )
 void prvJobsDemoTask( void * pvParameters )
 {
     BaseType_t xDemoStatus = pdPASS;
+    UBaseType_t uxDemoRunCount = 0UL;
+    BaseType_t retryDemoLoop = pdFALSE;
 
     /* Remove compiler warnings about unused parameters. */
     ( void ) pvParameters;
@@ -742,6 +760,11 @@ void prvJobsDemoTask( void * pvParameters )
     /* Set the pParams member of the network context with desired transport. */
     xNetworkContext.pParams = &xTlsTransportParams;
 
+    /* This demo runs a single loop unless there are failures in the demo execution.
+     * In case of failures in the demo execution, demo loop will be retried for up to
+     * JOBS_MAX_DEMO_LOOP_COUNT times. */
+    do
+    {
         /* Establish an MQTT connection with AWS IoT over a mutually authenticated TLS session. */
         xDemoStatus = xEstablishMqttSession( &xMqttContext,
                                              &xNetworkContext,
@@ -839,12 +862,39 @@ void prvJobsDemoTask( void * pvParameters )
             }
         }
 
+        /* Increment the demo run count. */
+        uxDemoRunCount++;
+
+        /* Retry demo loop only if there is a failure before completing
+         * the processing of any pending jobs. Any failure in MQTT unsubscribe
+         * or disconnect is considered a failure in demo execution and retry
+         * will not be attempted since a retry without any pending jobs will
+         * make this demo indefinitely wait. */
+        if( ( xDemoStatus == pdFAIL ) || ( xDemoEncounteredError == pdTRUE ) )
+        {
+            if( uxDemoRunCount < JOBS_MAX_DEMO_LOOP_COUNT )
+            {
+                LogWarn( ( "Demo iteration %lu failed. Retrying...", uxDemoRunCount ) );
+                retryDemoLoop = pdTRUE;
+            }
+            else
+            {
+                LogError( ( "All %d demo iterations failed.", JOBS_MAX_DEMO_LOOP_COUNT ) );
+                retryDemoLoop = pdFALSE;
+            }
+        }
+        else
+        {
+            /* Reset the flag for demo retry. */
+            retryDemoLoop = pdFALSE;
+        }
+
         /* Unsubscribe from the NextJobExecutionChanged API topic. */
         if( xUnsubscribeFromTopic( &xMqttContext,
                                    NEXT_JOB_EXECUTION_CHANGED_TOPIC( democonfigTHING_NAME ),
                                    sizeof( NEXT_JOB_EXECUTION_CHANGED_TOPIC( democonfigTHING_NAME ) ) - 1 ) != pdPASS )
         {
-        xDemoStatus == pdFAIL;
+            xDemoStatus = pdFAIL;
             LogError( ( "Failed to subscribe unsubscribe from the NextJobExecutionChanged API of AWS IoT Jobs service: "
                         "Topic=%s", NEXT_JOB_EXECUTION_CHANGED_TOPIC( democonfigTHING_NAME ) ) );
         }
@@ -852,10 +902,22 @@ void prvJobsDemoTask( void * pvParameters )
         /* Disconnect the MQTT and network connections with AWS IoT. */
         if( xDisconnectMqttSession( &xMqttContext, &xNetworkContext ) != pdPASS )
         {
-        xDemoStatus == pdFAIL;
+            xDemoStatus = pdFAIL;
-        LogError( ( "Disconnection from AWS Iot failed..." ) );
+            LogError( ( "Disconnection from AWS IoT failed..." ) );
         }
 
+        /* Add a delay if a retry is required. */
+        if( retryDemoLoop == pdTRUE )
+        {
+            /* Clear the flag that indicates that indicates the demo error
+             * before attempting a retry. */
+            xDemoEncounteredError = pdFALSE;
+
+            LogInfo( ( "A short delay before the next demo iteration." ) );
+            vTaskDelay( DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS );
+        }
+    } while( retryDemoLoop == pdTRUE );
+
     if( ( xDemoEncounteredError == pdFALSE ) && ( xDemoStatus == pdPASS ) )
     {
         LogInfo( ( "Demo completed successfully." ) );

FreeRTOS-Plus/Demo/coreHTTP_Windows_Simulator/HTTP_Mutual_Auth/DemoTasks/MutualAuthHTTPExample.c

@@ -128,6 +128,22 @@ struct NetworkContext
     TlsTransportParams_t * pParams;
 };
 
+/**
+ * @brief The maximum number of times to run the loop in this demo.
+ *
+ * @note The demo loop is attempted to re-run only if it fails in an iteration.
+ * Once the demo loop succeeds in an iteration, the demo exits successfully.
+ */
+#ifndef HTTP_MAX_DEMO_LOOP_COUNT
+    #define HTTP_MAX_DEMO_LOOP_COUNT    ( 3 )
+#endif
+
+/**
+ * @brief Time in ticks to wait between retries of the demo loop if
+ * demo loop fails.
+ */
+#define DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS    ( pdMS_TO_TICKS( 5000U ) )
+
 /**
  * @brief A buffer used in the demo for storing HTTP request headers and
  * HTTP response headers and body.
@@ -215,6 +231,7 @@ static void prvHTTPDemoTask( void * pvParameters )
     NetworkContext_t xNetworkContext = { 0 };
     TlsTransportParams_t xTlsTransportParams = { 0 };
     BaseType_t xIsConnectionEstablished = pdFALSE;
+    UBaseType_t uxDemoRunCount = 0UL;
 
     /* The user of this demo must check the logs for any failure codes. */
     BaseType_t xDemoStatus = pdPASS;
@@ -225,6 +242,11 @@ static void prvHTTPDemoTask( void * pvParameters )
     /* Set the pParams member of the network context with desired transport. */
     xNetworkContext.pParams = &xTlsTransportParams;
 
+    /* This demo runs a single loop unless there are failures in the demo execution.
+     * In case of failures in the demo execution, demo loop will be retried for up to
+     * HTTP_MAX_DEMO_LOOP_COUNT times. */
+    do
+    {
         /**************************** Connect. ******************************/
 
         /* Attempt to connect to the HTTP server. If connection fails, retry after a
@@ -275,6 +297,29 @@ static void prvHTTPDemoTask( void * pvParameters )
             TLS_FreeRTOS_Disconnect( &xNetworkContext );
         }
 
+        /*********************** Retry in case of failure. ************************/
+
+        /* Increment the demo run count. */
+        uxDemoRunCount++;
+
+        if( xDemoStatus == pdPASS )
+        {
+            LogInfo( ( "Demo iteration %lu was successful.", uxDemoRunCount ) );
+        }
+        /* Attempt to retry a failed demo iteration for up to #HTTP_MAX_DEMO_LOOP_COUNT times. */
+        else if( uxDemoRunCount < HTTP_MAX_DEMO_LOOP_COUNT )
+        {
+            LogWarn( ( "Demo iteration %lu failed. Retrying...", uxDemoRunCount ) );
+            vTaskDelay( DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS );
+        }
+        /* Failed all #HTTP_MAX_DEMO_LOOP_COUNT demo iterations. */
+        else
+        {
+            LogError( ( "All %d demo iterations failed.", HTTP_MAX_DEMO_LOOP_COUNT ) );
+            break;
+        }
+    } while( xDemoStatus != pdPASS );
+
     if( xDemoStatus == pdPASS )
     {
         LogInfo( ( "prvHTTPDemoTask() completed successfully. "

FreeRTOS-Plus/Demo/coreHTTP_Windows_Simulator/HTTP_Plaintext/DemoTasks/PlainTextHTTPExample.c

@@ -170,6 +170,22 @@ struct NetworkContext
     PlaintextTransportParams_t * pParams;
 };
 
+/**
+ * @brief The maximum number of times to run the loop in this demo.
+ *
+ * @note The demo loop is attempted to re-run only if it fails in an iteration.
+ * Once the demo loop succeeds in an iteration, the demo exits successfully.
+ */
+#ifndef HTTP_MAX_DEMO_LOOP_COUNT
+    #define HTTP_MAX_DEMO_LOOP_COUNT    ( 3 )
+#endif
+
+/**
+ * @brief Time in ticks to wait between retries of the demo loop if
+ * demo loop fails.
+ */
+#define DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS    ( pdMS_TO_TICKS( 5000U ) )
+
 /**
  * @brief A pair containing a path string of the URI and its length.
  */
@@ -294,6 +310,7 @@ static void prvHTTPDemoTask( void * pvParameters )
     };
     BaseType_t xIsConnectionEstablished = pdFALSE;
     UBaseType_t uxHttpPathCount = 0U;
+    UBaseType_t uxDemoRunCount = 0UL;
 
     /* The user of this demo must check the logs for any failure codes. */
     BaseType_t xDemoStatus = pdPASS;
@@ -304,6 +321,11 @@ static void prvHTTPDemoTask( void * pvParameters )
     /* Set the pParams member of the network context with desired transport. */
     xNetworkContext.pParams = &xPlaintextTransportParams;
 
+    /* This demo runs a single loop unless there are failures in the demo execution.
+     * In case of failures in the demo execution, demo loop will be retried for up to
+     * HTTP_MAX_DEMO_LOOP_COUNT times. */
+    do
+    {
         /**************************** Connect. ******************************/
 
         /* Attempt to connect to the HTTP server. If connection fails, retry after a
@@ -361,6 +383,29 @@ static void prvHTTPDemoTask( void * pvParameters )
             Plaintext_FreeRTOS_Disconnect( &xNetworkContext );
         }
 
+        /*********************** Retry in case of failure. ************************/
+
+        /* Increment the demo run count. */
+        uxDemoRunCount++;
+
+        if( xDemoStatus == pdPASS )
+        {
+            LogInfo( ( "Demo iteration %lu was successful.", uxDemoRunCount ) );
+        }
+        /* Attempt to retry a failed demo iteration for up to #HTTP_MAX_DEMO_LOOP_COUNT times. */
+        else if( uxDemoRunCount < HTTP_MAX_DEMO_LOOP_COUNT )
+        {
+            LogWarn( ( "Demo iteration %lu failed. Retrying...", uxDemoRunCount ) );
+            vTaskDelay( DELAY_BETWEEN_DEMO_RETRY_ITERATIONS_TICKS );
+        }
+        /* Failed all #HTTP_MAX_DEMO_LOOP_COUNT demo iterations. */
+        else
+        {
+            LogError( ( "All %d demo iterations failed.", HTTP_MAX_DEMO_LOOP_COUNT ) );
+            break;
+        }
+    } while( xDemoStatus != pdPASS );
+
     if( xDemoStatus == pdPASS )
     {
         LogInfo( ( "prvHTTPDemoTask() completed successfully. "