New feature: write header message at start of logging (both file and socket) or file flush. Includes configuration parameter: audit_header_msg to control if header message enabled/disabled (default enabled).

include/audit_handler.h

@@ -12,6 +12,7 @@
 #include <yajl/yajl_gen.h>
 
 #define AUDIT_LOG_PREFIX "Audit Plugin:"
+#define AUDIT_PROTOCOL_VERSION "1.0"
 
 class THD;
 
@@ -267,13 +268,20 @@ public:
 
     static const char * DEF_MSG_DELIMITER;
 
-    Audit_json_formatter(): m_msg_delimiter(NULL)
+    Audit_json_formatter(): m_msg_delimiter(NULL), m_write_start_msg(true)
     {
         config.beautify = 0;
         config.indentString = NULL;
     }
     virtual ~Audit_json_formatter() {}
     virtual ssize_t event_format(ThdSesData *pThdData, IWriter * writer);
+	virtual ssize_t start_msg_format(IWriter * writer);
+
+	/**
+	 * Boolean indicating if to log start msg.
+	 * Public so sysvar can update.
+	 */
+	my_bool m_write_start_msg;
 
     /**
      * Message delimiter. Should point to a valid json string (supporting the json escapping format).

src/audit_handler.cc

@@ -389,6 +389,45 @@ static const char * thd_query_str(THD * thd, size_t * len)
 }
 #endif
 
+ssize_t Audit_json_formatter::start_msg_format(IWriter * writer)
+{
+    if(!m_write_start_msg) //disabled
+    {
+        return 0;
+    }
+	//initialize yajl
+    yajl_gen gen = yajl_gen_alloc(&config, NULL);
+    yajl_gen_map_open(gen);
+    yajl_add_string_val(gen, "msg-type", "header");
+	uint64 ts = my_getsystime() / (10000);
+	yajl_add_uint64(gen, "date", ts);
+	yajl_add_string_val(gen, "audit-version", MYSQL_AUDIT_PLUGIN_VERSION"-"MYSQL_AUDIT_PLUGIN_REVISION);
+	yajl_add_string_val(gen, "audit-protocol-version", AUDIT_PROTOCOL_VERSION);	
+	yajl_add_string_val(gen, "hostname", glob_hostname);
+	yajl_add_string_val(gen, "mysql-version", server_version);	
+	yajl_add_string_val(gen, "mysql-program", my_progname);	
+	yajl_add_string_val(gen, "mysql-socket", mysqld_unix_port);	
+	yajl_add_uint64(gen, "mysql-port", mysqld_port);	
+	ssize_t res = -2;
+	yajl_gen_status stat = yajl_gen_map_close(gen); //close the object
+    if(stat == yajl_gen_status_ok) //all is good write the buffer out
+    {
+        const unsigned char * text = NULL;
+        unsigned int len = 0;
+        yajl_gen_get_buf(gen, &text, &len);
+        //print the json
+        res = writer->write((const char *)text, len);
+        if(res >= 0)
+        {
+            //TODO: use the msg_delimiter
+            res = writer->write("\n", 1);
+        }
+        //my_fwrite(log_file, (uchar *) b.data, json_size(&b), MYF(0));
+    }
+    yajl_gen_free(gen); //free the generator
+    return res;
+	
+}
 
 ssize_t Audit_json_formatter::event_format(ThdSesData* pThdData, IWriter * writer)
 {

src/audit_plugin.cc

@@ -2089,7 +2089,7 @@ static struct st_mysql_show_var audit_status[] =
         (char *) MYSQL_AUDIT_PLUGIN_VERSION "-" MYSQL_AUDIT_PLUGIN_REVISION,
         SHOW_CHAR },
 { "Audit_protocol_version",
-		(char *) "1.0",
+		(char *) AUDIT_PROTOCOL_VERSION,
 		SHOW_CHAR },
 //{"called",     (char *)&number_of_calls, SHOW_LONG},
         { 0, 0, (enum_mysql_show_type) 0 } };
@@ -2134,6 +2134,9 @@ static void json_log_socket_enable(THD *thd, struct st_mysql_sys_var *var,
 
 //setup sysvars which update directly the relevant plugins
 
+static MYSQL_SYSVAR_BOOL(header_msg, json_formatter.m_write_start_msg,
+             PLUGIN_VAR_RQCMDARG,
+        "AUDIT write header message at start of logging or file flush Enable|Disable. Default enabled.", NULL, NULL, 1);
 
 static MYSQL_SYSVAR_STR(json_log_file, json_file_handler.m_filename,
         PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
@@ -2218,6 +2221,7 @@ static MYSQL_SYSVAR_STR(record_objs, record_objs_string,
  */
 static struct st_mysql_sys_var* audit_system_variables[] =
 {
+        MYSQL_SYSVAR(header_msg),
         MYSQL_SYSVAR(json_log_file),
         MYSQL_SYSVAR(json_file_sync),
         MYSQL_SYSVAR(json_file),