MXS-936: add shutdown hooks

First part: add shutdown hooks for routers.

Binlog is the first one with a  destroyInstance() routine

include/maxscale/router.h

@@ -24,6 +24,7 @@
  * 16/07/2013   Massimiliano Pinto  Added router commands values
  * 22/10/2013   Massimiliano Pinto  Added router errorReply entry point
  * 27/10/2015   Martin Brampton     Add RCAP_TYPE_NO_RSESSION
+ * 08/11/2016   Massimiliano Pinto  Add destroyInstance() entry point
  *
  */
 
@@ -82,6 +83,7 @@ typedef struct router_object
                            error_action_t action,
                            bool*          succp);
     uint64_t (*getCapabilities)(void);
+    void    (*destroyInstance)(SERVICE *service);
 } ROUTER_OBJECT;
 
 /**

server/core/service.c

@@ -34,6 +34,7 @@
  * 03/03/15     Massimiliano Pinto      Added config_enable_feedback_task() call in serviceStartAll
  * 19/06/15     Martin Brampton         More meaningful names for temp variables
  * 31/05/16     Martin Brampton         Implement connection throttling
+ * 08/11/16     Massimiliano Pinto      Added: service_shutdown() calls destroyInstance() hoosk for routers
  *
  * @endverbatim
  */
@@ -1827,6 +1828,11 @@ void service_shutdown()
     while (svc != NULL)
     {
         svc->svc_do_shutdown = true;
+        /* Call destroyInstance hook for routers */
+        if (svc->router->destroyInstance)
+        {
+           svc->router->destroyInstance(svc);
+        }
         svc = svc->next;
     }
     spinlock_release(&service_spin);

server/modules/routing/avro/avro.c

@@ -105,7 +105,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     clientReply,
     errorReply,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 static SPINLOCK instlock;

server/modules/routing/binlog/blr.c

@@ -50,6 +50,7 @@
  *                                  for connection error and authentication failure.
  * 11/07/2016   Massimiliano Pinto  Added SSL backend support
  * 22/07/2016   Massimiliano Pinto  Added semi_sync replication support
+ * 08/11/2016   Massimiliano Pinto  Added destroyInstance()
  *
  * @endverbatim
  */
@@ -108,6 +109,7 @@ static int blr_check_binlog(ROUTER_INSTANCE *router);
 int blr_read_events_all_events(ROUTER_INSTANCE *router, int fix, int debug);
 void blr_master_close(ROUTER_INSTANCE *);
 void blr_free_ssl_data(ROUTER_INSTANCE *inst);
+static void destroyInstance(SERVICE *service);
 
 /** The module object definition */
 static ROUTER_OBJECT MyObject =
@@ -120,7 +122,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     clientReply,
     errorReply,
-    getCapabilities
+    getCapabilities,
+    destroyInstance
 };
 
 static void stats_func(void *);
@@ -2291,3 +2294,65 @@ blr_free_ssl_data(ROUTER_INSTANCE *inst)
         inst->service->dbref->server->server_ssl = NULL;
     }
 }
+
+/**
+ * destroy binlog server instance
+ *
+ * @param service   The service this router instance belongs to
+ */
+static void
+destroyInstance(SERVICE *service)
+{
+    ROUTER_INSTANCE *inst = (ROUTER_INSTANCE *) service->router_instance;
+
+    MXS_DEBUG("Destroying instance of router %s for service %s",
+              service->routerModule, service->name);
+
+    /* Check whether master connection is active */
+    if (inst->master)
+    {
+        if (inst->master->fd != -1 && inst->master->state == DCB_STATE_POLLING)
+        {
+            blr_master_close(inst);
+        }
+    }
+
+    spinlock_acquire(&inst->lock);
+
+    if (inst->master_state != BLRM_UNCONFIGURED)
+    {
+        inst->master_state = BLRM_SLAVE_STOPPED;
+    }
+
+    if (inst->client)
+    {
+        if (inst->client->state == DCB_STATE_POLLING)
+        {
+            dcb_close(inst->client);
+            inst->client = NULL;
+        }
+    }
+
+    /* Discard the queued residual data */
+    while (inst->residual)
+    {
+        inst->residual = gwbuf_consume(inst->residual, GWBUF_LENGTH(inst->residual));
+    }
+    inst->residual = NULL;
+
+    MXS_NOTICE("%s is being stopped by MaxScale shudown. Disconnecting from master %s:%d, "
+               "read up to log %s, pos %lu, transaction safe pos %lu",
+               service->name,
+               service->dbref->server->name,
+               service->dbref->server->port,
+               inst->binlog_name, inst->current_pos, inst->binlog_position);
+
+    if (inst->trx_safe && inst->pending_transaction)
+    {
+        MXS_WARNING("%s stopped by shutdown: detected mid-transaction in binlog file %s, "
+                    "pos %lu, incomplete transaction starts at pos %lu",
+                    service->name, inst->binlog_name, inst->current_pos, inst->binlog_position);
+    }
+
+    spinlock_release(&inst->lock);
+}

server/modules/routing/cli/cli.c

@@ -71,7 +71,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     NULL,
     NULL,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 extern int execute_cmd(CLI_SESSION *cli);

server/modules/routing/debugcli/debugcli.c

@@ -70,7 +70,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     NULL,
     NULL,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 extern int execute_cmd(CLI_SESSION *cli);

server/modules/routing/maxinfo/maxinfo.c

@@ -96,7 +96,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     NULL,
     handleError,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 static SPINLOCK     instlock;

server/modules/routing/readconnroute/readconnroute.c

@@ -125,7 +125,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     clientReply,
     handleError,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 static bool rses_begin_locked_router_action(ROUTER_CLIENT_SES* rses);

server/modules/routing/readwritesplit/readwritesplit.c

@@ -101,7 +101,8 @@ static ROUTER_OBJECT MyObject =
     diagnostics,
     clientReply,
     handleError,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 /*

server/modules/routing/schemarouter/schemarouter.c

@@ -113,7 +113,8 @@ static ROUTER_OBJECT MyObject =
     diagnostic,
     clientReply,
     handleError,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 static bool rses_begin_locked_router_action(ROUTER_CLIENT_SES* rses);

server/modules/routing/testroute/testroute.c

@@ -50,7 +50,8 @@ static ROUTER_OBJECT MyObject =
     diagnostic,
     clientReply,
     handleError,
-    getCapabilities
+    getCapabilities,
+    NULL
 };
 
 typedef struct

server/modules/routing/webserver/webserver.c

@@ -64,7 +64,8 @@ static ROUTER_OBJECT MyObject =
     diagnostic,
     NULL,
     NULL,
-    getCapabilities
+    getCapabilities,
+    NULL
 };