a196420c2d
This removes parts of the nearly identical code from all monitors. The removal of monitor type specific event checking is done based on the assumption that only the monitor that is monitoring the server can be the cause for a state change. This removes the need to actually check that the state change is relevant for each monitor and allows the event handling to be moved into the core.
299 lines
8.2 KiB
C
299 lines
8.2 KiB
C
/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl.
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*
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* Change Date: 2019-07-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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/**
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* @file auroramon.c - Amazon RDS Aurora monitor
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*/
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#include <maxscale/modinfo.h>
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#include <maxscale/thread.h>
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#include <maxscale/monitor.h>
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#include <mysqld_error.h>
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#include <maxscale/alloc.h>
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#include <maxscale/debug.h>
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typedef struct aurora_monitor
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{
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bool shutdown; /**< True if the monitor is stopped */
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THREAD thread; /**< Monitor thread */
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char* script; /**< Launchable script */
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uint64_t events; /**< Enabled monitor events */
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} AURORA_MONITOR;
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/**
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* @brief Update the status of a server
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*
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* This function connects to the database and queries it for its status. The
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* status of the server is adjusted accordingly based on the results of the
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* query.
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*
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* @param monitor Monitor object
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* @param database Server whose status should be updated
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*/
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void update_server_status(MONITOR *monitor, MONITOR_SERVERS *database)
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{
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if (!SERVER_IN_MAINT(database->server))
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{
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SERVER temp_server = {.status = database->server->status};
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server_clear_status_nolock(&temp_server, SERVER_RUNNING | SERVER_MASTER | SERVER_SLAVE | SERVER_AUTH_ERROR);
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database->mon_prev_status = database->server->status;
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/** Try to connect to or ping the database */
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connect_result_t rval = mon_connect_to_db(monitor, database);
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if (rval == MONITOR_CONN_OK)
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{
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server_set_status_nolock(&temp_server, SERVER_RUNNING);
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MYSQL_RES *result;
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/** Connection is OK, query for replica status */
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if (mysql_query(database->con, "SELECT @@aurora_server_id, server_id FROM "
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"information_schema.replica_host_status "
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"WHERE session_id = 'MASTER_SESSION_ID'") == 0 &&
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(result = mysql_store_result(database->con)))
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{
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ss_dassert(mysql_field_count(database->con) == 2);
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MYSQL_ROW row = mysql_fetch_row(result);
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int status = SERVER_SLAVE;
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/** The master will return a row with two identical non-NULL fields */
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if (row[0] && row[1] && strcmp(row[0], row[1]) == 0)
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{
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status = SERVER_MASTER;
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}
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server_set_status_nolock(&temp_server, status);
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mysql_free_result(result);
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}
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else
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{
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MXS_ERROR("Failed to query server %s (%s:%d): %d, %s",
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database->server->unique_name, database->server->name,
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database->server->port, mysql_errno(database->con),
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mysql_error(database->con));
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}
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}
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else
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{
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/** Failed to connect to the database */
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if (mysql_errno(database->con) == ER_ACCESS_DENIED_ERROR)
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{
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server_set_status_nolock(&temp_server, SERVER_AUTH_ERROR);
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}
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if (mon_status_changed(database) && mon_print_fail_status(database))
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{
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mon_log_connect_error(database, rval);
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}
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}
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server_transfer_status(database->server, &temp_server);
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}
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}
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/**
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* @brief Main monitoring loop
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*
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* @param arg The MONITOR object for this monitor
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*/
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static void
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monitorMain(void *arg)
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{
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MONITOR *monitor = (MONITOR*)arg;
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AURORA_MONITOR *handle = monitor->handle;
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if (mysql_thread_init())
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{
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MXS_ERROR("mysql_thread_init failed in Aurora monitor. Exiting.");
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return;
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}
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while (!handle->shutdown)
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{
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lock_monitor_servers(monitor);
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servers_status_pending_to_current(monitor);
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for (MONITOR_SERVERS *ptr = monitor->databases; ptr; ptr = ptr->next)
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{
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update_server_status(monitor, ptr);
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if (SERVER_IS_DOWN(ptr->server))
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{
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/** Hang up all DCBs connected to the failed server */
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dcb_hangup_foreach(ptr->server);
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}
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}
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/**
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* After updating the status of all servers, check if monitor events
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* need to be launched.
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*/
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mon_process_state_changes(monitor, handle->script, handle->events);
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servers_status_current_to_pending(monitor);
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release_monitor_servers(monitor);
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/** Sleep until the next monitoring interval */
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int ms = 0;
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while (ms < monitor->interval && !handle->shutdown)
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{
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if (monitor->server_pending_changes)
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{
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// Admin has changed something, skip sleep
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break;
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}
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thread_millisleep(MON_BASE_INTERVAL_MS);
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ms += MON_BASE_INTERVAL_MS;
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}
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}
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mysql_thread_end();
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}
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/**
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* Helper function to free the monitor handle
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*/
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static void auroramon_free(AURORA_MONITOR *handle)
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{
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if (handle)
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{
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MXS_FREE(handle->script);
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MXS_FREE(handle);
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}
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}
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/**
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* @brief Start the monitor
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*
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* This function initializes the monitor and starts the monitoring thread.
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*
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* @param arg The MONITOR structure for this monitor
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* @param opt The configuration parameters for this monitor
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* @return Monitor handle
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*/
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static void *
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startMonitor(MONITOR *mon, const CONFIG_PARAMETER *params)
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{
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AURORA_MONITOR *handle = mon->handle;
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if (handle)
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{
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handle->shutdown = false;
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MXS_FREE(handle->script);
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}
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else
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{
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if ((handle = (AURORA_MONITOR *) MXS_MALLOC(sizeof(AURORA_MONITOR))) == NULL)
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{
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return NULL;
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}
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handle->shutdown = false;
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if (!check_monitor_permissions(mon, "SELECT @@aurora_server_id, server_id FROM "
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"information_schema.replica_host_status "
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"WHERE session_id = 'MASTER_SESSION_ID'"))
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{
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MXS_ERROR("Failed to start monitor. See earlier errors for more information.");
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auroramon_free(handle);
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return NULL;
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}
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}
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handle->script = config_copy_string(params, "script");
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handle->events = config_get_enum(params, "events", monitor_event_enum_values);
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if (thread_start(&handle->thread, monitorMain, mon) == NULL)
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{
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MXS_ERROR("Failed to start monitor thread for monitor '%s'.", mon->name);
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auroramon_free(handle);
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return NULL;
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}
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return handle;
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}
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/**
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* Stop a running monitor
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*
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* @param arg Handle on thr running monior
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*/
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static void
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stopMonitor(MONITOR *mon)
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{
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AURORA_MONITOR *handle = (AURORA_MONITOR *) mon->handle;
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handle->shutdown = true;
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thread_wait(handle->thread);
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}
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/**
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* Diagnostic interface
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*
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* @param dcb DCB to send output
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* @param mon The monitor
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*/
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static void
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diagnostics(DCB *dcb, const MONITOR *mon)
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{
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}
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/**
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* The module entry point routine. It is this routine that must populate the
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* structure that is referred to as the "module object", this is a structure
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* with the set of external entry points for this module.
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*
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* @return The module object
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*/
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MXS_MODULE* MXS_CREATE_MODULE()
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{
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static MONITOR_OBJECT MyObject =
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{
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startMonitor,
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stopMonitor,
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diagnostics
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};
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static MXS_MODULE info =
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{
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MXS_MODULE_API_MONITOR,
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MXS_MODULE_BETA_RELEASE,
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MONITOR_VERSION,
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"Aurora monitor",
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"V1.0.0",
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&MyObject,
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NULL, /* Process init. */
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NULL, /* Process finish. */
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NULL, /* Thread init. */
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NULL, /* Thread finish. */
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{
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{
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"script",
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MXS_MODULE_PARAM_PATH,
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NULL,
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MXS_MODULE_OPT_PATH_X_OK
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},
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{
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"events",
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MXS_MODULE_PARAM_ENUM,
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MONITOR_EVENT_DEFAULT_VALUE,
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MXS_MODULE_OPT_NONE,
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monitor_event_enum_values
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},
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{MXS_END_MODULE_PARAMS}
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}
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};
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return &info;
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}
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