Doc:latest/evalguide/csa104m - Revision history

Stone: /* The Code */

2013-01-15T16:16:41Z

‎The Code

Stone at 20:17, 11 January 2013

2013-01-11T20:17:10Z

Stone at 20:11, 11 January 2013

2013-01-11T20:11:45Z

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Stone: /* How to Run csa104 and What to Observe */

2013-01-11T20:09:42Z

‎How to Run csa104 and What to Observe

Stone: /* How to Run csa103 and What to Observe */

2013-01-11T19:49:59Z

‎How to Run csa103 and What to Observe

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Stone: /* Putting it all Together */

2013-01-11T19:25:25Z

‎Putting it all Together

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Stone: /* The Code */

2013-01-11T18:46:18Z

‎The Code

Stone: /* The Code */

2013-01-11T18:23:36Z

‎The Code

Stone: Created page with "==csa104 Messaging== Messaging refers to communications between components within the cluster. SAFplus provides a SA-Forum compliant implementation of the messaging service. I…"

2013-01-11T16:44:07Z

Created page with "==csa104 Messaging== Messaging refers to communications between components within the cluster. SAFplus provides a SA-Forum compliant implementation of the messaging service. I…"

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@@ Line 20: / Line 20: @@
   <SAFplus_installation_dir>/src/examples/eval/src/app/csa104Comp
-All messaging code has been isolated into a single module that consists of 2 files: msgFns.c and msgFns.h to increase readability.  These files provide the following APIs.
+To increase readability, all messaging code has been isolated into a single module that consists of 2 files: msgFns.c and msgFns.h.  These files provide the following APIs.
@@ Line 34: / Line 34: @@
 |}
-These APIs constitute the basic operations of any messaging library; initialize, open, send and receive.
+These APIs constitute the basic operations required by any application that uses messaging; initialize, open, send and receive.
 The following constants are also defined:

← Older revision		Revision as of 20:17, 11 January 2013
Line 566:		Line 566:
	And message passing resumes!		And message passing resumes!

		+	===Further Investigation===
		+
		+	The following are a few changes that you can make to continue investigating the message service:
		+
		+	* Add a new "reply" queue so the active can send the standby messages.
		+	* Use the saMsgMessageSendReceive and saMsgMessageReply functions to implement send/reply semantics.
		+	* Using the IDE, change the component's fault escalation behavior so that it fails over the first time the process is killed rather then restarting.
		+	* Investigate message queue groups.

	===Summary and References===		===Summary and References===

@@ Line 421: / Line 421: @@
 # kill 3301
 </pre></code>
 After killing the active component you should see lines in the log files like the following:
@@ Line 474: / Line 472: @@
 ==> var/log/csa104CompI1Log.latest <==
 Fri Jan 11 14:43:27.403 2013 (SCNodeI0.3302 : csa104Comp.---.---.00156 :   INFO) csa104: Sending Message: Msg  142 from csa104CompI1
    </pre></code>
 |}
 ===csa203===

← Older revision		Revision as of 18:46, 11 January 2013
Line 119:		Line 119:
	</pre></code>		</pre></code>
	\|}		\|}
		+
		+
		+	====Transmission====
		+
		+	Message transmission uses the saMsgMessageSend API which allows the application to pass a message buffer and a bunch of meta-data (such as message version, sender's name, etc) that will be sent to the receiver:
		+
		+	{\| cellspacing="0" cellpadding = "0" border="0" align = "center" width="680"
		+	! style="color:black;background-color:#ffccaa;" align="center"\| msgFns.c
		+	\|-
		+	\|<code><pre>
		+	SaAisErrorT msgSend(const char* queuename, void* buffer, int length)
		+	{
		+	SaAisErrorT rc;
		+	SaNameT saQueueName;
		+	SaMsgMessageT message;
		+
		+	/* Load the SAF string */
		+	saQueueName.length=strlen(queuename);
		+	memcpy(saQueueName.value,queuename,saQueueName.length+1);
		+
		+	/* Load the SAF message structure */
		+	message.type = 0;
		+	message.version.releaseCode = 0;
		+	message.version.majorVersion=0;
		+	message.version.minorVersion=0;
		+	message.senderName = 0; /* You could put a SaNameT* in here if you wanted to pass a reply queue (for example) */
		+	message.size = length;
		+	message.data = buffer;
		+	message.priority = SA_MSG_MESSAGE_HIGHEST_PRIORITY;
		+	rc = saMsgMessageSend (msgLibraryHandle, &saQueueName, &message, SA_TIME_MAX);
		+	if (SA_AIS_OK != rc)
		+	{
		+	/* Error 0xC here means that the queue has not yet been created.
		+	That is, the receiver is not yet listening. */
		+	clprintf ( CL_LOG_SEV_ERROR, "Msg saMsgMessageSend to queue [%s] failed [0x%X]", saQueueName.value,rc );
		+	}
		+	return rc;
		+	}
		+	</pre></code>
		+	\|}
		+
		+	For simplicity, this example creates the destination SaNameT and the SaMsgMessageT structures each time a message is sent. However, for efficiency when sending multiple messages to the same destination it is preferred to pre-create and reuse these objects.
		+
		+	====Receipt====
		+
		+	This example will create a dedicated message receiver thread and run the following code within that thread:
		+
		+	{\| cellspacing="0" cellpadding = "0" border="0" align = "center" width="680"
		+	! style="color:black;background-color:#ffccaa;" align="center"\| msgFns.c
		+	\|-
		+	\|<code><pre>
		+	void* msgReceiverLoop(void * notused)
		+	{
		+	SaAisErrorT rc;
		+	SaNameT SenderName;
		+	char Data[1024];
		+	SaMsgSenderIdT SenderId;
		+	SaTimeT SendTime;
		+
		+	while(1)
		+	{
		+
		+	SaMsgMessageT message = {
		+	.size = 1024,
		+	.senderName = &SenderName,
		+	.data = Data,
		+	};
		+
		+	rc = saMsgMessageGet (msgQueueHandle, &message, & SendTime, & SenderId, SA_TIME_MAX);
		+	if (SA_AIS_OK != rc)
		+	{
		+	clprintf ( CL_LOG_SEV_ERROR, "Msg saMsgMessageGet failed [0x%X]\n\r", rc );
		+	break;
		+	}
		+
		+	if (message.senderName->length)
		+	{
		+	clprintf ( CL_LOG_SEV_INFO, "Sender Name : %s\n", message.senderName->value);
		+	}
		+	clprintf ( CL_LOG_SEV_INFO, "Received Message : %s\n", (char *)message.data);
		+
		+	}
		+
		+	rc = saMsgQueueClose (msgQueueHandle);
		+	if (SA_AIS_OK != rc)
		+	{
		+	clprintf ( CL_LOG_SEV_ERROR, "Msg Queue Close failed [0x%X]\n\r", rc );
		+	}
		+	return 0;
		+
		+	}
		+	</pre></code>
		+	\|}
		+
		+	This code simply loops "forever" receiving messages and printing the contents of the message. If anything goes wrong it kicks itself out of the message processing loop and closes the message queue. Closing the queue will allow some other application to open it, in effect "taking over" the queue. If an application is killed or disappears due to node death (or other events) the AMF will close all queues opened by the application. This allow the new active application to take control of the queue.
		+
		+
		+	====Putting it all Together====

@@ Line 20: / Line 20: @@
   <SAFplus_installation_dir>/src/examples/eval/src/app/csa104Comp
-All messaging APIs have been isolated into a single module that consists of 2 files: msgFns.c and msgFns.h.  These files provide the following APIs.
+All messaging code has been isolated into a single module that consists of 2 files: msgFns.c and msgFns.h to increase readability.  These files provide the following APIs.
@@ Line 34: / Line 34: @@
 |}
-And define the following constants:
+The following constants are also defined:
@@ Line 46: / Line 47: @@
    </pre></code>
 |}