Add current master host:port to server read only error when available

Summary:
When a server is in read_only, we append the current master_host and
master_port to the error message, if the server is a slave. The master_host
could be either hostname or ip address, depending on how a slave is connected
to the master.

A new generic error code `ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO` is added, so
that we can append any additional info to the fixed error message.

Test Plan:
Updated rpl.rpl_read_only. Master_port is non-deterministic in the test, so I
masked in the test result.

Will update any test that comes up in the sandcastle if needed.

Reviewers: santoshb

Reviewed By: santoshb

Subscribers: webscalesql-eng, ebergen

Differential Revision: https://reviews.facebook.net/D61383

Author: tianx

mysql-test/suite/rpl/r/rpl_read_only.result

@@ -118,9 +118,9 @@ a
 2004
 2005
 insert into t1 values(1006);
-ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement
+ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement. Current master_host: 127.0.0.1, master_port: MASTER_PORT
 insert into t2 values(2006);
-ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement
+ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement. Current master_host: 127.0.0.1, master_port: MASTER_PORT
 drop user test;
 drop table t1;
 drop table t2;

mysql-test/suite/rpl/t/rpl_read_only.test

@@ -113,9 +113,11 @@ select * from t2;
 
 # Non root user can not write on the slave
 connection slave2;
---error ER_OPTION_PREVENTS_STATEMENT
+--replace_result $MASTER_MYPORT MASTER_PORT
+--error ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO
 insert into t1 values(1006);
---error ER_OPTION_PREVENTS_STATEMENT
+--replace_result $MASTER_MYPORT MASTER_PORT
+--error ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO
 insert into t2 values(2006);
 
 # Verify read_only cannot be disabled on slave

sql/handler.cc

@@ -32,6 +32,7 @@
 #include "discover.h"           // writefrm
 #include "log_event.h"          // *_rows_log_event
 #include "rpl_filter.h"
+#include "rpl_slave.h"
 #include <myisampack.h>
 #include "transaction.h"
 #include <errno.h>
@@ -1493,13 +1494,15 @@ int ha_commit_trans(THD *thd, bool all, bool async,
     // repository tables.
     if (rw_trans && check_ro(thd) && !ignore_global_read_lock)
     {
+      std::string extra_info;
+      int nr = get_active_master_info(&extra_info);
       if (opt_super_readonly)
       {
-        my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only (super)");
+        my_error(nr, MYF(0), "--read-only (super)", extra_info.c_str());
       }
       else
       {
-        my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only");
+        my_error(nr, MYF(0), "--read-only", extra_info.c_str());
       }
       ha_rollback_trans(thd, all);
       error= 1;

sql/share/errmsg-utf8.txt

@@ -7227,6 +7227,8 @@ ER_GIT_HASH
 ER_CONNECTION_TIMEOUT
   eng "Closed connection: idle timeout after %us"
 
+ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO
+  eng "The MySQL server is running with the %s option so it cannot execute this statement. %s"
 #
 #  End of 5.6 error messages.
 #

sql/sql_parse.cc

@@ -3137,13 +3137,15 @@ mysql_execute_command(THD *thd,
     */
     if (deny_updates_if_read_only_option(thd, all_tables))
     {
+      std::string extra_info;
+      int nr = get_active_master_info(&extra_info);
       if (opt_super_readonly)
       {
-        my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only (super)");
+        my_error(nr, MYF(0), "--read-only (super)", extra_info.c_str());
       }
       else
       {
-        my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only");
+        my_error(nr, MYF(0), "--read-only", extra_info.c_str());
       }
       DBUG_RETURN(-1);
     }
@@ -4132,13 +4134,15 @@ case SQLCOM_PREPARE:
         break;
       if (check_ro(thd) && some_non_temp_table_to_be_updated(thd, all_tables))
       {
+        std::string extra_info;
+        int nr = get_active_master_info(&extra_info);
         if (opt_super_readonly)
         {
-          my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only (super)");
+          my_error(nr, MYF(0), "--read-only (super)", extra_info.c_str());
         }
         else
         {
-          my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only");
+          my_error(nr, MYF(0), "--read-only", extra_info.c_str());
         }
 	break;
       }
@@ -9900,3 +9904,24 @@ THD* get_opt_thread_with_data_lock(THD *thd, ulong thread_id)
 
   return ret_thd;
 }
+
+// This function will generate the string containing current master host and
+// port info if available.
+//
+// Return value:
+//   ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO, if master info is available.
+//   ER_OPTION_PREVENTS_STATEMENT, if master info is not available.
+int get_active_master_info(std::string *str_ptr)
+{
+#ifdef HAVE_REPLICATION
+    if (str_ptr && active_mi && active_mi->host && active_mi->host[0])
+    {
+      *str_ptr = "Current master_host: ";
+      *str_ptr += active_mi->host;
+      *str_ptr += ", master_port: ";
+      *str_ptr += std::to_string(active_mi->port);
+      return ER_OPTION_PREVENTS_STATEMENT_EXTRA_INFO;
+    }
+#endif
+    return ER_OPTION_PREVENTS_STATEMENT;
+}

sql/sql_parse.h

@@ -263,4 +263,6 @@ inline bool is_supported_parser_charset(const CHARSET_INFO *cs)
 
 extern "C" bool sqlcom_can_generate_row_events(const THD *thd);
 
+int get_active_master_info(std::string *str);
+
 #endif /* SQL_PARSE_INCLUDED */