Changes to prepare for Jobs Library Demo (#401)

* Add submodule pointer to the aws/jobs-for-aws-iot-embedded-sdk repository for the Jobs library
* Commonize the MQTT helper functions used by the Device Shadow demo by re-locating them to FreeRTOS-Plus/Demo/AWS/MQTT_Demo_Helpers and updating the Device Shadow demo to use the new files

5 files changed, 186 insertions, 158 deletions

diff --git a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c
index 5547a4db2..7fde51167 100644..100755
--- a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c
+++ b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/ShadowDemoMainExample.c
@@ -62,10 +62,10 @@
 /* JSON library includes. */
 #include "core_json.h"
 
-/* Shadow demo helpers header. */
-#include "shadow_demo_helpers.h"
+/* Include MQTT demo helpers header. */
+#include "mqtt_demo_helpers.h"
 
-/* Demo Specific configs. */
+/* Demo Specific config file. */
 #include "demo_config.h"
 
 
@@ -148,24 +148,42 @@
  */
 #define SHADOW_REPORTED_JSON_LENGTH    ( sizeof( SHADOW_REPORTED_JSON ) - 3 )
 
-#ifndef THING_NAME
+/*------------- Demo configurations -------------------------*/
+
+#ifndef democonfigTHING_NAME
+    #define democonfigTHING_NAME    democonfigCLIENT_IDENTIFIER
+#endif
 
 /**
- * @brief Predefined thing name.
- *
- * This is the example predefine thing name and could be compiled in ROM code.
+ * @brief The length of #democonfigTHING_NAME.
  */
-    #define THING_NAME    democonfigCLIENT_IDENTIFIER
-#endif
+#define THING_NAME_LENGTH    ( ( uint16_t ) ( sizeof( democonfigTHING_NAME ) - 1 ) )
+
+/*-----------------------------------------------------------*/
 
 /**
- * @brief The length of #THING_NAME.
+ * @brief The MQTT context used for MQTT operation.
  */
-#define THING_NAME_LENGTH    ( ( uint16_t ) ( sizeof( THING_NAME ) - 1 ) )
+static MQTTContext_t xMqttContext;
 
+/**
+ * @brief The network context used for mbedTLS operation.
+ */
+static NetworkContext_t xNetworkContext;
 
+/**
+ * @brief Static buffer used to hold MQTT messages being sent and received.
+ */
+static uint8_t ucSharedBuffer[ democonfigNETWORK_BUFFER_SIZE ];
 
-/*-----------------------------------------------------------*/
+/**
+ * @brief Static buffer used to hold MQTT messages being sent and received.
+ */
+static MQTTFixedBuffer_t xBuffer =
+{
+    .pBuffer = ucSharedBuffer,
+    .size    = democonfigNETWORK_BUFFER_SIZE
+};
 
 /**
  * @brief The simulated device current power on state.
@@ -523,14 +541,15 @@ static void prvEventCallback( MQTTContext_t * pxMqttContext,
 /*-----------------------------------------------------------*/
 
 /*
- * @brief Create the task that demonstrates the Shadow API Demo via a
- * MQTT mutually authenticated network connection with MQTT broker.
+ * @brief Create the task that demonstrates the Device Shadow library API via a
+ * MQTT mutually authenticated network connection with the AWS IoT broker.
  */
 void vStartShadowDemo( void )
 {
     /* This example uses a single application task, which shows that how to
-     * use Device Shadow library to get shadow topics and validate shadow topics
-     * via MQTT APIs communicating with the MQTT broker. */
+     * use Device Shadow library to generate and validate AWS IoT Device Shadow
+     * MQTT topics, and use the coreMQTT library to communicate with the AWS IoT
+     * Device Shadow service. */
     xTaskCreate( prvShadowDemoTask,        /* Function that implements the task. */
                  "DemoTask",               /* Text name for the task - only used for debugging. */
                  democonfigDEMO_STACKSIZE, /* Size of stack (in words, not bytes) to allocate for the task. */
@@ -538,7 +557,6 @@ void vStartShadowDemo( void )
                  tskIDLE_PRIORITY,         /* Task priority, must be between 0 and configMAX_PRIORITIES - 1. */
                  NULL );                   /* Used to pass out a handle to the created task - not used in this case. */
 }
-
 /*-----------------------------------------------------------*/
 
 /**
@@ -564,14 +582,17 @@ void prvShadowDemoTask( void * pvParameters )
 {
     BaseType_t demoStatus = pdPASS;
 
-    /* Remove compiler warnings about unused parameters. */
-    ( void ) pvParameters;
-
     /* A buffer containing the update document. It has static duration to prevent
      * it from being placed on the call stack. */
     static char pcUpdateDocument[ SHADOW_REPORTED_JSON_LENGTH + 1 ] = { 0 };
 
-    demoStatus = xEstablishMqttSession( prvEventCallback );
+    /* Remove compiler warnings about unused parameters. */
+    ( void ) pvParameters;
+
+    demoStatus = xEstablishMqttSession( &xMqttContext,
+                                        &xNetworkContext,
+                                        &xBuffer,
+                                        prvEventCallback );
 
     if( pdFAIL == demoStatus )
     {
@@ -581,7 +602,8 @@ void prvShadowDemoTask( void * pvParameters )
     else
     {
         /* First of all, try to delete any Shadow document in the cloud. */
-        demoStatus = xPublishToTopic( SHADOW_TOPIC_STRING_DELETE( THING_NAME ),
+        demoStatus = xPublishToTopic( &xMqttContext,
+                                      SHADOW_TOPIC_STRING_DELETE( democonfigTHING_NAME ),
                                       SHADOW_TOPIC_LENGTH_DELETE( THING_NAME_LENGTH ),
                                       pcUpdateDocument,
                                       0U );
@@ -589,23 +611,26 @@ void prvShadowDemoTask( void * pvParameters )
         /* Then try to subscribe shadow topics. */
         if( demoStatus == pdPASS )
         {
-            demoStatus = xSubscribeToTopic( SHADOW_TOPIC_STRING_UPDATE_DELTA( THING_NAME ),
+            demoStatus = xSubscribeToTopic( &xMqttContext,
+                                            SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ),
                                             SHADOW_TOPIC_LENGTH_UPDATE_DELTA( THING_NAME_LENGTH ) );
         }
 
         if( demoStatus == pdPASS )
         {
-            demoStatus = xSubscribeToTopic( SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( THING_NAME ),
+            demoStatus = xSubscribeToTopic( &xMqttContext,
+                                            SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ),
                                             SHADOW_TOPIC_LENGTH_UPDATE_ACCEPTED( THING_NAME_LENGTH ) );
         }
 
         if( demoStatus == pdPASS )
         {
-            demoStatus = xSubscribeToTopic( SHADOW_TOPIC_STRING_UPDATE_REJECTED( THING_NAME ),
+            demoStatus = xSubscribeToTopic( &xMqttContext,
+                                            SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ),
                                             SHADOW_TOPIC_LENGTH_UPDATE_REJECTED( THING_NAME_LENGTH ) );
         }
 
-        /* This demo uses a constant #THING_NAME known at compile time therefore we can use macros to
+        /* This demo uses a constant #democonfigTHING_NAME known at compile time therefore we can use macros to
          * assemble shadow topic strings.
          * If the thing name is known at run time, then we could use the API #Shadow_GetTopicString to
          * assemble shadow topic strings, here is the example for /update/delta:
@@ -651,7 +676,8 @@ void prvShadowDemoTask( void * pvParameters )
                       ( int ) 1,
                       ( long unsigned ) ( xTaskGetTickCount() % 1000000 ) );
 
-            demoStatus = xPublishToTopic( SHADOW_TOPIC_STRING_UPDATE( THING_NAME ),
+            demoStatus = xPublishToTopic( &xMqttContext,
+                                          SHADOW_TOPIC_STRING_UPDATE( democonfigTHING_NAME ),
                                           SHADOW_TOPIC_LENGTH_UPDATE( THING_NAME_LENGTH ),
                                           pcUpdateDocument,
                                           ( SHADOW_DESIRED_JSON_LENGTH + 1 ) );
@@ -683,7 +709,8 @@ void prvShadowDemoTask( void * pvParameters )
                           ( int ) ulCurrentPowerOnState,
                           ( long unsigned ) ulClientToken );
 
-                demoStatus = xPublishToTopic( SHADOW_TOPIC_STRING_UPDATE( THING_NAME ),
+                demoStatus = xPublishToTopic( &xMqttContext,
+                                              SHADOW_TOPIC_STRING_UPDATE( democonfigTHING_NAME ),
                                               SHADOW_TOPIC_LENGTH_UPDATE( THING_NAME_LENGTH ),
                                               pcUpdateDocument,
                                               ( SHADOW_DESIRED_JSON_LENGTH + 1 ) );
@@ -698,42 +725,45 @@ void prvShadowDemoTask( void * pvParameters )
         {
             LogInfo( ( "Start to unsubscribe shadow topics and disconnect from MQTT. \r\n" ) );
 
-            demoStatus = xUnsubscribeFromTopic( SHADOW_TOPIC_STRING_UPDATE_DELTA( THING_NAME ),
+            demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+                                                SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ),
                                                 SHADOW_TOPIC_LENGTH_UPDATE_DELTA( THING_NAME_LENGTH ) );
 
             if( demoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
-                            SHADOW_TOPIC_STRING_UPDATE_DELTA( THING_NAME ) ) );
+                            SHADOW_TOPIC_STRING_UPDATE_DELTA( democonfigTHING_NAME ) ) );
             }
         }
 
         if( demoStatus == pdPASS )
         {
-            demoStatus = xUnsubscribeFromTopic( SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( THING_NAME ),
+            demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+                                                SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ),
                                                 SHADOW_TOPIC_LENGTH_UPDATE_ACCEPTED( THING_NAME_LENGTH ) );
 
             if( demoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
-                            SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( THING_NAME ) ) );
+                            SHADOW_TOPIC_STRING_UPDATE_ACCEPTED( democonfigTHING_NAME ) ) );
             }
         }
 
         if( demoStatus == pdPASS )
         {
-            demoStatus = xUnsubscribeFromTopic( SHADOW_TOPIC_STRING_UPDATE_REJECTED( THING_NAME ),
+            demoStatus = xUnsubscribeFromTopic( &xMqttContext,
+                                                SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ),
                                                 SHADOW_TOPIC_LENGTH_UPDATE_REJECTED( THING_NAME_LENGTH ) );
 
             if( demoStatus != pdPASS )
             {
                 LogError( ( "Failed to unsubscribe the topic %s",
-                            SHADOW_TOPIC_STRING_UPDATE_REJECTED( THING_NAME ) ) );
+                            SHADOW_TOPIC_STRING_UPDATE_REJECTED( democonfigTHING_NAME ) ) );
             }
         }
 
         /* The MQTT session is always disconnected, even there were prior failures. */
-        demoStatus = xDisconnectMqttSession();
+        demoStatus = 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,
diff --git a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/WIN32.vcxproj b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/WIN32.vcxproj
index b8940c63b..456d99a37 100644
--- a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/WIN32.vcxproj
+++ b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/WIN32.vcxproj
@@ -58,7 +58,7 @@
     </Midl>

     <ClCompile>

       <Optimization>Disabled</Optimization>

-      <AdditionalIncludeDirectories>..\..\..\..\..\Source\FreeRTOS-Plus-Trace\Include;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\include;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\portable\BufferManagement;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\portable\Compiler\MSVC;..\..\..\..\..\FreeRTOS-Plus\Source\Utilities\logging;..\common\WinPCap;..\..\..\..\..\FreeRTOS\Source\include;..\..\..\..\..\FreeRTOS\Source\portable\MSVC-MingW;..\..\..\..\Source\Application-Protocols\coreMQTT\source\include;..\..\..\..\Source\Application-Protocols\coreMQTT\source\interface;..\..\..\..\Source\Utilities\exponential_backoff;..\..\..\..\Source\Application-Protocols\network_transport\freertos_plus_tcp;..\..\..\..\Source\Application-Protocols\network_transport\freertos_plus_tcp\using_mbedtls;..\..\..\..\Source\Utilities\mbedtls_freertos;..\..\..\..\..\Source\mbedtls_utils;..\..\..\..\ThirdParty\mbedtls\include;..\..\..\..\Source\AWS\device-shadow\source\include;..\..\..\..\Source\coreJSON\source\include;.;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>

+      <AdditionalIncludeDirectories>..\..\..\..\..\Source\FreeRTOS-Plus-Trace\Include;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\include;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\portable\BufferManagement;..\..\..\..\..\FreeRTOS-Plus\Source\FreeRTOS-Plus-TCP\portable\Compiler\MSVC;..\..\..\..\..\FreeRTOS-Plus\Source\Utilities\logging;..\common\WinPCap;..\..\..\..\..\FreeRTOS\Source\include;..\..\..\..\..\FreeRTOS\Source\portable\MSVC-MingW;..\..\..\..\Source\Application-Protocols\coreMQTT\source\include;..\..\..\..\Source\Application-Protocols\coreMQTT\source\interface;..\..\..\..\Source\Utilities\exponential_backoff;..\..\..\..\Source\Application-Protocols\network_transport\freertos_plus_tcp;..\..\..\..\Source\Application-Protocols\network_transport\freertos_plus_tcp\using_mbedtls;..\..\..\..\Source\Utilities\mbedtls_freertos;..\..\..\..\..\Source\mbedtls_utils;..\..\..\..\ThirdParty\mbedtls\include;..\..\..\..\Source\AWS\device-shadow\source\include;..\..\..\..\Source\coreJSON\source\include;..\..\Mqtt_Demo_Helpers;.;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>

       <PreprocessorDefinitions>MBEDTLS_CONFIG_FILE="mbedtls_config.h";WIN32;_DEBUG;_CONSOLE;_WIN32_WINNT=0x0500;WINVER=0x400;_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>

       <MinimalRebuild>false</MinimalRebuild>

       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>

@@ -490,7 +490,7 @@
     <ClCompile Include="..\..\..\..\..\FreeRTOS-Plus\Demo\Common\Logging\windows\Logging_WinSim.c" />

     <ClCompile Include="..\Common\main.c" />

     <ClCompile Include="DemoTasks\ShadowDemoMainExample.c" />

-    <ClCompile Include="DemoTasks\shadow_demo_helpers.c" />

+    <ClCompile Include="..\..\Mqtt_Demo_Helpers\mqtt_demo_helpers.c" />

   </ItemGroup>

   <ItemGroup>

     <ClInclude Include="..\..\..\..\..\FreeRTOS\Source\include\event_groups.h" />

diff --git a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/demo_config.h b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/demo_config.h
index c0b6ec636..f20a12cb2 100644
--- a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/demo_config.h
+++ b/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/demo_config.h
@@ -67,6 +67,17 @@ extern void vLoggingPrintf( const char * pcFormatString,
 
 /************ End of logging configuration ****************/
 
+/**
+ * @brief The Thing resource registered on your AWS IoT account to use in the demo.
+ * A Thing resource is required to communicate with the AWS IoT Device Shadow service.
+ *
+ * @note The Things associated with your AWS account can be found in the
+ * AWS IoT console under Manage/Things, or using the ListThings REST API (that can
+ * be called with the AWS CLI command line tool).
+ *
+ * #define democonfigTHING_NAME    "...insert here..."
+ */
+
 #ifndef democonfigCLIENT_IDENTIFIER
 
 /**
@@ -83,16 +94,11 @@ extern void vLoggingPrintf( const char * pcFormatString,
 #endif
 
 /**
- * @brief Endpoint of the MQTT broker to connect to.
- *
- * This demo application can be run with any MQTT broker, that supports mutual
- * authentication.
- *
- * For AWS IoT MQTT broker, this is the Thing's REST API Endpoint.
+ * @brief The AWS IoT broker endpoint to connect to in the demo.
  *
  * @note Your AWS IoT Core endpoint can be found in the AWS IoT console under
- * Settings/Custom Endpoint, or using the describe-endpoint REST API (with
- * AWS CLI command line tool).
+ * Settings/Custom Endpoint, or using the DescribeEndpoint REST API (that can
+ * be called with AWS CLI command line tool).
  *
  * #define democonfigMQTT_BROKER_ENDPOINT    "...insert here..."
  */
@@ -113,8 +119,8 @@ extern void vLoggingPrintf( const char * pcFormatString,
 /**
  * @brief AWS root CA certificate.
  *
- * For AWS IoT MQTT broker, this certificate is used to identify the AWS IoT
- * server and is publicly available. Refer to the link below.
+ * This certificate is used to identify the AWS IoT server and is publicly available.
+ * Refer to the link below.
  * https://www.amazontrust.com/repository/AmazonRootCA1.pem
  *
  * @note This certificate should be PEM-encoded.
@@ -124,7 +130,6 @@ extern void vLoggingPrintf( const char * pcFormatString,
  * "...base64 data...\n"\
  * "-----END CERTIFICATE-----\n"
  *
- * #define democonfigROOT_CA_PEM    "...insert here..."
  */
 
 #define democonfigROOT_CA_PEM                                            \
@@ -152,7 +157,7 @@ extern void vLoggingPrintf( const char * pcFormatString,
 /**
  * @brief Client certificate.
  *
- * For AWS IoT MQTT broker, refer to the AWS documentation below for details
+ * Please refer to the AWS documentation below for details
  * regarding client authentication.
  * https://docs.aws.amazon.com/iot/latest/developerguide/client-authentication.html
  *
@@ -169,7 +174,7 @@ extern void vLoggingPrintf( const char * pcFormatString,
 /**
  * @brief Client's private key.
  *
- * For AWS IoT MQTT broker, refer to the AWS documentation below for details
+ * Please refer to the AWS documentation below for details
  * regarding clientauthentication.
  * https://docs.aws.amazon.com/iot/latest/developerguide/client-authentication.html
  *
@@ -187,7 +192,7 @@ extern void vLoggingPrintf( const char * pcFormatString,
  * @brief The username value for authenticating client to the MQTT broker when
  * username/password based client authentication is used.
  *
- * For AWS IoT MQTT broker, refer to the AWS IoT documentation below for
+ * Please refer to the AWS IoT documentation below for
  * details regarding client authentication with a username and password.
  * https://docs.aws.amazon.com/iot/latest/developerguide/custom-authentication.html
  * An authorizer setup needs to be done, as mentioned in the above link, to use
@@ -200,7 +205,7 @@ extern void vLoggingPrintf( const char * pcFormatString,
  * @brief The password value for authenticating client to the MQTT broker when
  * username/password based client authentication is used.
  *
- * For AWS IoT MQTT broker, refer to the AWS IoT documentation below for
+ * Please refer to the AWS IoT documentation below for
  * details regarding client authentication with a username and password.
  * https://docs.aws.amazon.com/iot/latest/developerguide/custom-authentication.html
  * An authorizer setup needs to be done, as mentioned in the above link, to use
diff --git a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/shadow_demo_helpers.c b/FreeRTOS-Plus/Demo/AWS/Mqtt_Demo_Helpers/mqtt_demo_helpers.c
index 4345ac90d..465d0eb08 100644..100755
--- a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/shadow_demo_helpers.c
+++ b/FreeRTOS-Plus/Demo/AWS/Mqtt_Demo_Helpers/mqtt_demo_helpers.c
@@ -41,10 +41,7 @@
 #include "task.h"
 
 /* Shadow includes */
-#include "shadow_demo_helpers.h"
-
-/* Demo Specific configs. */
-#include "demo_config.h"
+#include "mqtt_demo_helpers.h"
 
 /* MQTT library includes. */
 #include "core_mqtt.h"
@@ -55,32 +52,32 @@
 /* Transport interface implementation include header for TLS. */
 #include "using_mbedtls.h"
 
+/* Demo specific config. */
+#include "demo_config.h"
+
 /*------------- Demo configurations -------------------------*/
 
-/** Note: The device client certificate and private key credentials are
- * obtained by the TLS transport interface implementation from the
+/**
+ * Note: The TLS connection credentials for the server root CA certificate,
+ * and device client certificate and private key should be defined in the
  * demo_config.h file.
  */
 
+#ifndef democonfigROOT_CA_PEM
+    #error "Please define the AWS Root CA certificate (democonfigROOT_CA_PEM) in demo_config.h."
+#endif
 #ifndef democonfigCLIENT_PRIVATE_KEY_PEM
-    #error "Please define client private key(democonfigCLIENT_PRIVATE_KEY_PEM) in demo_config.h."
+    #error "Please define client private key (democonfigCLIENT_PRIVATE_KEY_PEM) in demo_config.h."
 #endif
 
 #ifndef democonfigCLIENT_CERTIFICATE_PEM
-    #error "Please define client certificate(democonfigCLIENT_CERTIFICATE_PEM) in demo_config.h."
+    #error "Please define client certificate (democonfigCLIENT_CERTIFICATE_PEM) in demo_config.h."
 #endif
 
 #ifndef democonfigMQTT_BROKER_ENDPOINT
-    #error "Please define democonfigMQTT_BROKER_ENDPOINT in demo_config.h."
+    #error "Please define the AWS IoT broker endpoint (democonfigMQTT_BROKER_ENDPOINT) in demo_config.h."
 #endif
 
-#ifndef democonfigMQTT_BROKER_PORT
-
-/**
- * @brief The port to use for the demo.
- */
-    #define democonfigMQTT_BROKER_PORT    ( 8883 )
-#endif
 /*-----------------------------------------------------------*/
 
 /**
@@ -162,6 +159,7 @@
  */
 #define AWS_IOT_MQTT_ALPN                "\x0ex-amzn-mqtt-ca"
 
+
 /*-----------------------------------------------------------*/
 
 /**
@@ -181,6 +179,8 @@ typedef struct PublishPackets
     MQTTPublishInfo_t pubInfo;
 } PublishPackets_t;
 
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Global entry time into the application to use as a reference timestamp
  * in the #prvGetTimeMs function. #prvGetTimeMs will always return the difference
@@ -189,7 +189,10 @@ typedef struct PublishPackets
  */
 static uint32_t ulGlobalEntryTimeMs;
 
-/*-----------------------------------------------------------*/
+/**
+ * @brief The flag to indicate the mqtt session changed.
+ */
+static BaseType_t xMqttSessionEstablished = pdFALSE;
 
 /**
  * @brief Packet Identifier generated when Subscribe request was sent to the broker;
@@ -211,35 +214,6 @@ static uint16_t globalUnsubscribePacketIdentifier = 0U;
  */
 static PublishPackets_t outgoingPublishPackets[ MAX_OUTGOING_PUBLISHES ] = { 0 };
 
-/**
- * @brief Static buffer used to hold MQTT messages being sent and received.
- */
-static uint8_t ucSharedBuffer[ democonfigNETWORK_BUFFER_SIZE ];
-
-/**
- * @brief The MQTT context used for MQTT operation.
- */
-static MQTTContext_t mqttContext = { 0 };
-
-/**
- * @brief The network context used for Openssl operation.
- */
-static NetworkContext_t networkContext = { 0 };
-
-/**
- * @brief The flag to indicate the mqtt session changed.
- */
-static bool mqttSessionEstablished = false;
-
-/**
- * @brief Static buffer used to hold MQTT messages being sent and received.
- */
-static MQTTFixedBuffer_t xBuffer =
-{
-    .pBuffer = ucSharedBuffer,
-    .size    = democonfigNETWORK_BUFFER_SIZE
-};
-
 /*-----------------------------------------------------------*/
 
 /**
@@ -319,6 +293,8 @@ static TlsTransportStatus_t prvConnectToServerWithBackoffRetries( NetworkContext
      * second entry must remain NULL. */
     char * pcAlpnProtocols[] = { NULL, NULL };
 
+    configASSERT( pxNetworkContext != NULL );
+
     /* Set the credentials for establishing a TLS connection. */
     xNetworkCredentials.pRootCa = ( const unsigned char * ) democonfigROOT_CA_PEM;
     xNetworkCredentials.rootCaSize = sizeof( democonfigROOT_CA_PEM );
@@ -381,7 +357,7 @@ static TlsTransportStatus_t prvConnectToServerWithBackoffRetries( NetworkContext
 
 static BaseType_t prvGetNextFreeIndexForOutgoingPublishes( uint8_t * pucIndex )
 {
-    BaseType_t returnStatus = pdFAIL;
+    BaseType_t xReturnStatus = pdFAIL;
     uint8_t ucIndex = 0;
 
     configASSERT( outgoingPublishPackets != NULL );
@@ -393,7 +369,7 @@ static BaseType_t prvGetNextFreeIndexForOutgoingPublishes( uint8_t * pucIndex )
          * Check if the the ucIndex has a free slot. */
         if( outgoingPublishPackets[ ucIndex ].packetId == MQTT_PACKET_ID_INVALID )
         {
-            returnStatus = pdPASS;
+            xReturnStatus = pdPASS;
             break;
         }
     }
@@ -401,7 +377,7 @@ static BaseType_t prvGetNextFreeIndexForOutgoingPublishes( uint8_t * pucIndex )
     /* Copy the available ucIndex into the output param. */
     *pucIndex = ucIndex;
 
-    return returnStatus;
+    return xReturnStatus;
 }
 /*-----------------------------------------------------------*/
 
@@ -494,7 +470,7 @@ void vHandleOtherIncomingPacket( MQTTPacketInfo_t * pxPacketInfo,
 
 static BaseType_t xHandlePublishResend( MQTTContext_t * pxMqttContext )
 {
-    BaseType_t returnStatus = pdTRUE;
+    BaseType_t xReturnStatus = pdTRUE;
     MQTTStatus_t xMQTTStatus = MQTTSuccess;
     uint8_t ucIndex = 0U;
 
@@ -521,7 +497,7 @@ static BaseType_t xHandlePublishResend( MQTTContext_t * pxMqttContext )
                             " failed with status %u.",
                             outgoingPublishPackets[ ucIndex ].packetId,
                             xMQTTStatus ) );
-                returnStatus = pdFAIL;
+                xReturnStatus = pdFAIL;
                 break;
             }
             else
@@ -532,19 +508,20 @@ static BaseType_t xHandlePublishResend( MQTTContext_t * pxMqttContext )
         }
     }
 
-    return returnStatus;
+    return xReturnStatus;
 }
 
 /*-----------------------------------------------------------*/
 
-BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
+BaseType_t xEstablishMqttSession( MQTTContext_t * pxMqttContext,
+                                  NetworkContext_t * pxNetworkContext,
+                                  MQTTFixedBuffer_t * pxNetworkBuffer,
+                                  MQTTEventCallback_t eventCallback )
 {
-    BaseType_t returnStatus = pdTRUE;
+    BaseType_t xReturnStatus = pdTRUE;
     MQTTStatus_t xMQTTStatus;
     MQTTConnectInfo_t xConnectInfo;
     TransportInterface_t xTransport;
-    MQTTContext_t * pxMqttContext = &mqttContext;
-    NetworkContext_t * pxNetworkContext = &networkContext;
     bool sessionPresent = false;
 
     configASSERT( pxMqttContext != NULL );
@@ -561,7 +538,7 @@ BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
         LogError( ( "Failed to connect to MQTT broker %.*s.",
                     strlen( democonfigMQTT_BROKER_ENDPOINT ),
                     democonfigMQTT_BROKER_ENDPOINT ) );
-        returnStatus = pdFAIL;
+        xReturnStatus = pdFAIL;
     }
     else
     {
@@ -575,11 +552,11 @@ BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
                                  &xTransport,
                                  prvGetTimeMs,
                                  eventCallback,
-                                 &xBuffer );
+                                 pxNetworkBuffer );
 
         if( xMQTTStatus != MQTTSuccess )
         {
-            returnStatus = pdFAIL;
+            xReturnStatus = pdFAIL;
             LogError( ( "MQTT init failed with status %u.", xMQTTStatus ) );
         }
         else
@@ -632,7 +609,7 @@ BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
 
             if( xMQTTStatus != MQTTSuccess )
             {
-                returnStatus = pdFAIL;
+                xReturnStatus = pdFAIL;
                 LogError( ( "Connection with MQTT broker failed with status %u.", xMQTTStatus ) );
             }
             else
@@ -641,15 +618,15 @@ BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
             }
         }
 
-        if( returnStatus == pdFAIL )
+        if( xReturnStatus == pdFAIL )
         {
             /* Keep a flag for indicating if MQTT session is established. This
              * flag will mark that an MQTT DISCONNECT has to be sent at the end
              * of the demo even if there are intermediate failures. */
-            mqttSessionEstablished = true;
+            xMqttSessionEstablished = true;
         }
 
-        if( returnStatus == pdFAIL )
+        if( xReturnStatus == pdFAIL )
         {
             /* Check if session is present and if there are any outgoing publishes
              * that need to resend. This is only valid if the broker is
@@ -674,23 +651,22 @@ BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback )
         }
     }
 
-    return returnStatus;
+    return xReturnStatus;
 }
 
 /*-----------------------------------------------------------*/
 
-BaseType_t xDisconnectMqttSession( void )
+BaseType_t xDisconnectMqttSession( MQTTContext_t * pxMqttContext,
+                                   NetworkContext_t * pxNetworkContext )
 {
     MQTTStatus_t xMQTTStatus = MQTTSuccess;
-    BaseType_t returnStatus = pdTRUE;
+    BaseType_t xReturnStatus = pdTRUE;
     TlsTransportStatus_t xNetworkStatus;
-    MQTTContext_t * pxMqttContext = &mqttContext;
-    NetworkContext_t * pxNetworkContext = &networkContext;
 
     configASSERT( pxMqttContext != NULL );
     configASSERT( pxNetworkContext != NULL );
 
-    if( mqttSessionEstablished == true )
+    if( xMqttSessionEstablished == true )
     {
         /* Send DISCONNECT. */
         xMQTTStatus = MQTT_Disconnect( pxMqttContext );
@@ -699,24 +675,24 @@ BaseType_t xDisconnectMqttSession( void )
         {
             LogError( ( "Sending MQTT DISCONNECT failed with status=%u.",
                         xMQTTStatus ) );
-            returnStatus = pdFAIL;
+            xReturnStatus = pdFAIL;
         }
     }
 
     /* Close the network connection.  */
     TLS_FreeRTOS_Disconnect( pxNetworkContext );
 
-    return returnStatus;
+    return xReturnStatus;
 }
 
 /*-----------------------------------------------------------*/
 
-BaseType_t xSubscribeToTopic( const char * pcTopicFilter,
+BaseType_t xSubscribeToTopic( MQTTContext_t * pxMqttContext,
+                              const char * pcTopicFilter,
                               uint16_t usTopicFilterLength )
 {
-    BaseType_t returnStatus = pdTRUE;
+    BaseType_t xReturnStatus = pdTRUE;
     MQTTStatus_t xMQTTStatus;
-    MQTTContext_t * pxMqttContext = &mqttContext;
     MQTTSubscribeInfo_t pSubscriptionList[ mqttexampleTOPIC_COUNT ];
 
     configASSERT( pxMqttContext != NULL );
@@ -744,7 +720,7 @@ BaseType_t xSubscribeToTopic( const char * pcTopicFilter,
     {
         LogError( ( "Failed to send SUBSCRIBE packet to broker with error = %u.",
                     xMQTTStatus ) );
-        returnStatus = pdFAIL;
+        xReturnStatus = pdFAIL;
     }
     else
     {
@@ -763,23 +739,23 @@ BaseType_t xSubscribeToTopic( const char * pcTopicFilter,
 
         if( xMQTTStatus != MQTTSuccess )
         {
-            returnStatus = pdFAIL;
+            xReturnStatus = pdFAIL;
             LogError( ( "MQTT_ProcessLoop returned with status = %u.",
                         xMQTTStatus ) );
         }
     }
 
-    return returnStatus;
+    return xReturnStatus;
 }
 
 /*-----------------------------------------------------------*/
 
-BaseType_t xUnsubscribeFromTopic( const char * pcTopicFilter,
+BaseType_t xUnsubscribeFromTopic( MQTTContext_t * pxMqttContext,
+                                  const char * pcTopicFilter,
                                   uint16_t usTopicFilterLength )
 {
-    BaseType_t returnStatus = pdTRUE;
+    BaseType_t xReturnStatus = pdTRUE;
     MQTTStatus_t xMQTTStatus;
-    MQTTContext_t * pxMqttContext = &mqttContext;
     MQTTSubscribeInfo_t pSubscriptionList[ 1 ];
 
     configASSERT( pxMqttContext != NULL );
@@ -807,7 +783,7 @@ BaseType_t xUnsubscribeFromTopic( const char * pcTopicFilter,
     {
         LogError( ( "Failed to send UNSUBSCRIBE packet to broker with error = %u.",
                     xMQTTStatus ) );
-        returnStatus = pdFAIL;
+        xReturnStatus = pdFAIL;
     }
     else
     {
@@ -820,26 +796,26 @@ BaseType_t xUnsubscribeFromTopic( const char * pcTopicFilter,
 
         if( xMQTTStatus != MQTTSuccess )
         {
-            returnStatus = pdFAIL;
+            xReturnStatus = pdFAIL;
             LogError( ( "MQTT_ProcessLoop returned with status = %u.",
                         xMQTTStatus ) );
         }
     }
 
-    return returnStatus;
+    return xReturnStatus;
 }
 
 /*-----------------------------------------------------------*/
 
-BaseType_t xPublishToTopic( const char * pcTopicFilter,
+BaseType_t xPublishToTopic( MQTTContext_t * pxMqttContext,
+                            const char * pcTopicFilter,
                             int32_t topicFilterLength,
                             const char * pcPayload,
                             size_t payloadLength )
 {
-    BaseType_t returnStatus = pdPASS;
+    BaseType_t xReturnStatus = pdPASS;
     MQTTStatus_t xMQTTStatus = MQTTSuccess;
     uint8_t ucPublishIndex = MAX_OUTGOING_PUBLISHES;
-    MQTTContext_t * pxMqttContext = &mqttContext;
 
     configASSERT( pxMqttContext != NULL );
     configASSERT( pcTopicFilter != NULL );
@@ -849,9 +825,9 @@ BaseType_t xPublishToTopic( const char * pcTopicFilter,
      * publishes are stored until a PUBACK is received. These messages are
      * stored for supporting a resend if a network connection is broken before
      * receiving a PUBACK. */
-    returnStatus = prvGetNextFreeIndexForOutgoingPublishes( &ucPublishIndex );
+    xReturnStatus = prvGetNextFreeIndexForOutgoingPublishes( &ucPublishIndex );
 
-    if( returnStatus == pdFAIL )
+    if( xReturnStatus == pdFAIL )
     {
         LogError( ( "Unable to find a free spot for outgoing PUBLISH message.\n\n" ) );
     }
@@ -878,7 +854,7 @@ BaseType_t xPublishToTopic( const char * pcTopicFilter,
             LogError( ( "Failed to send PUBLISH packet to broker with error = %u.",
                         xMQTTStatus ) );
             vCleanupOutgoingPublishAt( ucPublishIndex );
-            returnStatus = pdFAIL;
+            xReturnStatus = pdFAIL;
         }
         else
         {
@@ -899,12 +875,12 @@ BaseType_t xPublishToTopic( const char * pcTopicFilter,
             {
                 LogWarn( ( "MQTT_ProcessLoop returned with status = %u.",
                            xMQTTStatus ) );
-                returnStatus = pdFAIL;
+                xReturnStatus = pdFAIL;
             }
         }
     }
 
-    return returnStatus;
+    return xReturnStatus;
 }
 /*-----------------------------------------------------------*/
 
diff --git a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/shadow_demo_helpers.h b/FreeRTOS-Plus/Demo/AWS/Mqtt_Demo_Helpers/mqtt_demo_helpers.h
index cf7ad1e91..b6f803263 100644
--- a/FreeRTOS-Plus/Demo/AWS/Device_Shadow_Windows_Simulator/Device_Shadow_Demo/DemoTasks/shadow_demo_helpers.h
+++ b/FreeRTOS-Plus/Demo/AWS/Mqtt_Demo_Helpers/mqtt_demo_helpers.h
@@ -20,8 +20,8 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-#ifndef SHADOW_DEMO_HELPERS_H
-#define SHADOW_DEMO_HELPERS_H
+#ifndef MQTT_DEMO_HELPERS_H
+#define MQTT_DEMO_HELPERS_H
 
 /* MQTT API header. */
 #include "core_mqtt.h"
@@ -29,17 +29,24 @@
 /* Transport interface implementation include header for TLS. */
 #include "using_mbedtls.h"
 
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Establish a MQTT connection.
  *
- * @param[in] eventCallback The callback function used to receive incoming
+ * @param[in, out] pxMqttContext The memory for the MQTTContext_t that will be used for the
+ * MQTT connection.
+ * @param[out] pxNetworkContext The memory for the NetworkContext_t required for the
+ * MQTT connection.
+ * @param[in] pxNetworkBuffer The buffer space for initializing the @p pxMqttContext MQTT
+ * context used in the MQTT connection.
+ * @param[in] appCallback The callback function used to receive incoming
  * publishes and incoming acks from MQTT library.
  *
  * @return The status of the final connection attempt.
  */
-BaseType_t xEstablishMqttSession( MQTTEventCallback_t eventCallback );
+BaseType_t xEstablishMqttSession( MQTTContext_t * pxMqttContext,
+                                  NetworkContext_t * pxNetworkContext,
+                                  MQTTFixedBuffer_t * pxNetworkBuffer,
+                                  MQTTEventCallback_t eventCallback );
 
 /**
  * @brief Handle the incoming packet if it's not related to the device shadow.
@@ -53,41 +60,50 @@ void vHandleOtherIncomingPacket( MQTTPacketInfo_t * pxPacketInfo,
 /**
  * @brief Close the MQTT connection.
  *
+ * @param[in, out] pxMqttContext The MQTT context for the MQTT connection to close.
+ * @param[in, out] pxNetworkContext The network context for the TLS session to
+ * terminate.
+ *
  * @return pdPASS if DISCONNECT was successfully sent;
  * pdFAIL otherwise.
  */
-BaseType_t xDisconnectMqttSession( void );
+BaseType_t xDisconnectMqttSession( MQTTContext_t * pxMqttContext,
+                                   NetworkContext_t * pxNetworkContext );
 
 /**
  * @brief Subscribe to a MQTT topic filter.
  *
+ * @param[in] pxMqttContext The MQTT context for the MQTT connection to close.
  * @param[in] pcTopicFilter Pointer to the shadow topic buffer.
  * @param[in] usTopicFilterLength Indicates the length of the shadow
- * topic filter.
+ * topic buffer.
  *
  * @return pdPASS if SUBSCRIBE was successfully sent;
  * pdFAIL otherwise.
  */
-BaseType_t xSubscribeToTopic( const char * pcTopicFilter,
+BaseType_t xSubscribeToTopic( MQTTContext_t * pxMqttContext,
+                              const char * pcTopicFilter,
                               uint16_t usTopicFilterLength );
 
 /**
  * @brief Sends an MQTT UNSUBSCRIBE to unsubscribe from the shadow
  * topic.
  *
- * @param[in] pcTopicFilter Pointer to the shadow topic buffer.
- * @param[in] usTopicFilterLength Indicates the length of the shadow
- * topic filter.
+ * @param[in] pxMqttContext The MQTT context for the MQTT connection.
+ * @param[in] pcTopicFilter Pointer to the MQTT topic filter.
+ * @param[in] usTopicFilterLength Indicates the length of the topic filter.
  *
  * @return pdPASS if UNSUBSCRIBE was successfully sent;
  * pdFAIL otherwise.
  */
-BaseType_t xUnsubscribeFromTopic( const char * pcTopicFilter,
+BaseType_t xUnsubscribeFromTopic( MQTTContext_t * pxMqttContext,
+                                  const char * pcTopicFilter,
                                   uint16_t usTopicFilterLength );
 
 /**
  * @brief Publish a message to a MQTT topic.
  *
+ * @param[in] pxMqttContext The MQTT context for the MQTT connection.
  * @param[in] pcTopicFilter Points to the topic.
  * @param[in] topicFilterLength The length of the topic.
  * @param[in] pcPayload Points to the payload.
@@ -96,9 +112,10 @@ BaseType_t xUnsubscribeFromTopic( const char * pcTopicFilter,
  * @return pdPASS if PUBLISH was successfully sent;
  * pdFAIL otherwise.
  */
-BaseType_t xPublishToTopic( const char * pcTopicFilter,
+BaseType_t xPublishToTopic( MQTTContext_t * pxMqttContext,
+                            const char * pcTopicFilter,
                             int32_t topicFilterLength,
                             const char * pcPayload,
                             size_t payloadLength );
 
-#endif /* ifndef SHADOW_DEMO_HELPERS_H */
+#endif /* ifndef MQTT_DEMO_HELPERS_H */