From 8e9b7fb26a307018063fbf261e5ee0ea9f2d3897 Mon Sep 17 00:00:00 2001
From: Massimiliano Pinto <massimiliano.pinto@skysql.com>
Date: Tue, 22 Oct 2013 10:30:16 +0200
Subject: [PATCH] Added new entry point in router: errorReply

The routine if called from backend will ido:

1 reply error messages to client closing or not the session
2 open a new backend connection

An action flag is passed to the routine.
---
 server/include/router.h                       |  4 ++
 server/modules/routing/debugcli.c             |  1 +
 server/modules/routing/readconnroute.c        | 39 ++++++++++++++++++-
 .../routing/readwritesplit/readwritesplit.c   |  3 +-
 server/modules/routing/testroute.c            |  1 +
 5 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/server/include/router.h b/server/include/router.h
index 208b2f5df..9c93f3271 100644
--- a/server/include/router.h
+++ b/server/include/router.h
@@ -29,6 +29,7 @@
  * 					and the diagnostic entry point
  * 15/07/2013	Massimiliano Pinto	Added clientReply entry point
  * 16/07/2013	Massimiliano Pinto	Added router commands values
+ * 22/10/2013	Massimiliano Pinto	Added router errorReply entry point
  *
  */
 #include <service.h>
@@ -57,6 +58,8 @@ typedef void *ROUTER;
  * 	diagnostics		Called to force the router to print
  * 				diagnostic output
  *	clientReply		Called to reply to client the data from one or all backends
+ *	errorReply		Called to reply to client errors with optional closeSession or
+ *				make a request for a new backend connection
  *
  * @endverbatim
  *
@@ -70,6 +73,7 @@ typedef struct router_object {
 	int	(*routeQuery)(ROUTER *instance, void *router_session, GWBUF *queue);
 	void	(*diagnostics)(ROUTER *instance, DCB *dcb);
 	void    (*clientReply)(ROUTER* instance, void* router_session, GWBUF* queue, DCB *backend_dcb);
+	void    (*errorReply)(ROUTER* instance, void* router_session, char* message, DCB *backend_dcb, int action);
 } ROUTER_OBJECT;
 
 /* Router commands */
diff --git a/server/modules/routing/debugcli.c b/server/modules/routing/debugcli.c
index 2b407b45c..c4dccb47d 100644
--- a/server/modules/routing/debugcli.c
+++ b/server/modules/routing/debugcli.c
@@ -61,6 +61,7 @@ static ROUTER_OBJECT MyObject = {
     freeSession,
     execute,
     diagnostics,
+    NULL,
     NULL
 };
 
diff --git a/server/modules/routing/readconnroute.c b/server/modules/routing/readconnroute.c
index 2c262f2d4..137c8d50a 100644
--- a/server/modules/routing/readconnroute.c
+++ b/server/modules/routing/readconnroute.c
@@ -61,6 +61,8 @@
  * 31/07/2013	Massimiliano Pinto	Added a check for candidate server, if NULL return
  * 12/08/2013	Mark Riddoch		Log unsupported router options
  * 04/09/2013	Massimiliano Pinto	Added client NULL check in clientReply
+ * 22/10/2013	Massimiliano Pinto	errorReply called from backend, for client error replyi
+ *					or take different actions such as open a new backend connection
  *
  * @endverbatim
  */
@@ -96,6 +98,12 @@ static  void    clientReply(
         void    *router_session,
         GWBUF   *queue,
         DCB     *backend_dcb);
+static  void    errorReply(
+        ROUTER  *instance,
+        void    *router_session,
+        char    *message,
+        DCB     *backend_dcb,
+        int     action);
 
 /** The module object definition */
 static ROUTER_OBJECT MyObject = {
@@ -105,7 +113,8 @@ static ROUTER_OBJECT MyObject = {
     freeSession,
     routeQuery,
     diagnostics,
-    clientReply
+    clientReply,
+    errorReply
 };
 
 static SPINLOCK	instlock;
@@ -584,3 +593,31 @@ clientReply(
 	client->func.write(client, queue);
 }
 
+/**
+ * Error Reply routine
+ *
+ * The routine will reply to client errors and/or closing the session
+ * or try to open a new backend connection.
+ *
+ * @param       instance        The router instance
+ * @param       router_session  The router session
+ * @param       message         The error message to reply
+ * @param       backend_dcb     The backend DCB
+ * @param       action     	The action: REPLY, REPLY_AND_CLOSE, NEW_CONNECTION
+ *
+ */
+static  void
+errorReply(
+        ROUTER *instance,
+        void   *router_session,
+        char  *message,
+        DCB    *backend_dcb,
+        int     action)
+{
+	DCB		*client = NULL;
+	ROUTER_OBJECT   *router = NULL;
+	SESSION         *session = backend_dcb->session;
+	client = backend_dcb->session->client;
+
+	ss_dassert(client != NULL);
+}
diff --git a/server/modules/routing/readwritesplit/readwritesplit.c b/server/modules/routing/readwritesplit/readwritesplit.c
index 53f398214..ee5993bac 100644
--- a/server/modules/routing/readwritesplit/readwritesplit.c
+++ b/server/modules/routing/readwritesplit/readwritesplit.c
@@ -77,7 +77,8 @@ static ROUTER_OBJECT MyObject = {
         freeSession,
         routeQuery,
         diagnostic,
-        clientReply
+        clientReply,
+	NULL
 };
 
 static SPINLOCK	        instlock;
diff --git a/server/modules/routing/testroute.c b/server/modules/routing/testroute.c
index d31ccac92..2e1615f25 100644
--- a/server/modules/routing/testroute.c
+++ b/server/modules/routing/testroute.c
@@ -35,6 +35,7 @@ static ROUTER_OBJECT MyObject = {
     freeSession,
     routeQuery,
     diagnostic,
+    NULL,
     NULL
 };