mariadb/server-tools/instance-manager/guardian.cc
unknown 26b6b1b2a2 Cleanup the instance manager code.
BitKeeper/deleted/.del-factory.h~c1679505d3a6dd53:
  Delete: server-tools/instance-manager/factory.h
BitKeeper/deleted/.del-factory.cc~6836cccd4cd35b4d:
  Delete: server-tools/instance-manager/factory.cc
server-tools/instance-manager/Makefile.am:
  - remove Commands_factory: it'll be needed when we add support
  for NNTP/HTTP connections, currently it only adds unnecessary
  complexity.
server-tools/instance-manager/commands.cc:
  - fix coding style: no else after return; fix comments, make
  one place a bit faster.
server-tools/instance-manager/guardian.cc:
  - fix coding style and comments.
  - we must register the current thread in the thread registry
    before entering pthread_cond_timedwait, because at shutdown
    the thread registry will try to kick out of wait all blocked 
    threads. Unregistered threads are not awakened by the registry. 
    This fixes the failinig assert in Thread_registry::~Thread_registry
    at shutdown, when shutdown is requested and there is an
    instance monitored by Guardian.
server-tools/instance-manager/guardian.h:
  - fix coding style: enums must start with enum_
server-tools/instance-manager/instance.h:
  - move comment to the variable it comments
server-tools/instance-manager/instance_map.cc:
  - cleanup
server-tools/instance-manager/instance_options.cc:
  - cleanup; no else after return (fix coding style).
server-tools/instance-manager/manager.cc:
  - fix alignment; make some code easier to read.
server-tools/instance-manager/mysql_connection.cc:
  - remove Commands_factory
server-tools/instance-manager/options.cc:
  - fix a possible crash when the instance manager is started with
  --no-defaults --defaults-file=~/.my.cnf: if we return
  without cloning saved_argv by calling load_defaults, Options::cleanup
  will crash on attempt to free_defaults(saved_argv);
server-tools/instance-manager/parse.cc:
  - get rid of Commands_factory
server-tools/instance-manager/parse.h:
  - get rid of Commands_factory
server-tools/instance-manager/parse_output.cc:
  - in parse_output_and_get_value return error also if the specified
    pattern was not found, or the command failed to execute.
server-tools/instance-manager/portability.h:
  - fix coding style (// comments are allowed only at ends of lines)
server-tools/instance-manager/thread_registry.cc:
  - implement Thread_registry::cond_timedwait
server-tools/instance-manager/thread_registry.h:
  - implement Thread_registry::cond_timedwait; remove
    unused out parameter from Thread_registry::cond_wait.
server-tools/instance-manager/user_map.cc:
  - safety: newline can take 2 bytes.
2005-08-29 23:29:35 +04:00

439 lines
11 KiB
C++

/* Copyright (C) 2004 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifdef __GNUC__
#pragma implementation
#endif
#include "guardian.h"
#include "instance_map.h"
#include "instance.h"
#include "mysql_manager_error.h"
#include "log.h"
#include "portability.h"
#include <string.h>
#include <sys/types.h>
#include <signal.h>
C_MODE_START
pthread_handler_decl(guardian, arg)
{
Guardian_thread *guardian_thread= (Guardian_thread *) arg;
guardian_thread->run();
return 0;
}
C_MODE_END
Guardian_thread::Guardian_thread(Thread_registry &thread_registry_arg,
Instance_map *instance_map_arg,
uint monitoring_interval_arg) :
Guardian_thread_args(thread_registry_arg, instance_map_arg,
monitoring_interval_arg),
thread_info(pthread_self()), guarded_instances(0)
{
pthread_mutex_init(&LOCK_guardian, 0);
pthread_cond_init(&COND_guardian, 0);
shutdown_requested= FALSE;
stopped= FALSE;
init_alloc_root(&alloc, MEM_ROOT_BLOCK_SIZE, 0);
}
Guardian_thread::~Guardian_thread()
{
/* delay guardian destruction to the moment when no one needs it */
pthread_mutex_lock(&LOCK_guardian);
free_root(&alloc, MYF(0));
pthread_mutex_unlock(&LOCK_guardian);
pthread_mutex_destroy(&LOCK_guardian);
pthread_cond_destroy(&COND_guardian);
}
void Guardian_thread::request_shutdown(bool stop_instances_arg)
{
pthread_mutex_lock(&LOCK_guardian);
/* stop instances or just clean up Guardian repository */
stop_instances(stop_instances_arg);
shutdown_requested= TRUE;
pthread_mutex_unlock(&LOCK_guardian);
}
void Guardian_thread::process_instance(Instance *instance,
GUARD_NODE *current_node,
LIST **guarded_instances,
LIST *node)
{
uint waitchild= (uint) Instance::DEFAULT_SHUTDOWN_DELAY;
/* The amount of times, Guardian attempts to restart an instance */
int restart_retry= 100;
time_t current_time= time(NULL);
if (current_node->state == STOPPING)
{
/* this brach is executed during shutdown */
if (instance->options.shutdown_delay_val)
waitchild= instance->options.shutdown_delay_val;
/* this returns true if and only if an instance was stopped for sure */
if (instance->is_crashed())
*guarded_instances= list_delete(*guarded_instances, node);
else if ( (uint) (current_time - current_node->last_checked) > waitchild)
{
instance->kill_instance(SIGKILL);
/*
Later we do node= node->next. This is ok, as we are only removing
the node from the list. The pointer to the next one is still valid.
*/
*guarded_instances= list_delete(*guarded_instances, node);
}
return;
}
if (instance->is_running())
{
/* clear status fields */
current_node->restart_counter= 0;
current_node->crash_moment= 0;
current_node->state= STARTED;
}
else
{
switch (current_node->state) {
case NOT_STARTED:
instance->start();
current_node->last_checked= current_time;
log_info("guardian: starting instance %s",
instance->options.instance_name);
current_node->state= STARTING;
break;
case STARTED: /* fallthrough */
case STARTING: /* let the instance start or crash */
if (instance->is_crashed())
{
current_node->crash_moment= current_time;
current_node->last_checked= current_time;
current_node->state= JUST_CRASHED;
/* fallthrough -- restart an instance immediately */
}
else
break;
case JUST_CRASHED:
if (current_time - current_node->crash_moment <= 2)
{
instance->start();
log_info("guardian: starting instance %s",
instance->options.instance_name);
}
else
current_node->state= CRASHED;
break;
case CRASHED: /* just regular restarts */
if (current_time - current_node->last_checked >
monitoring_interval)
{
if ((current_node->restart_counter < restart_retry))
{
instance->start();
current_node->last_checked= current_time;
current_node->restart_counter++;
log_info("guardian: restarting instance %s",
instance->options.instance_name);
}
else
current_node->state= CRASHED_AND_ABANDONED;
}
break;
case CRASHED_AND_ABANDONED:
break; /* do nothing */
default:
DBUG_ASSERT(0);
}
}
}
/*
Run guardian thread
SYNOPSYS
run()
DESCRIPTION
Check for all guarded instances and restart them if needed. If everything
is fine go and sleep for some time.
*/
void Guardian_thread::run()
{
Instance *instance;
LIST *node;
struct timespec timeout;
thread_registry.register_thread(&thread_info);
my_thread_init();
pthread_mutex_lock(&LOCK_guardian);
/* loop, until all instances were shut down at the end */
while (!(shutdown_requested && (guarded_instances == NULL)))
{
node= guarded_instances;
while (node != NULL)
{
struct timespec timeout;
GUARD_NODE *current_node= (GUARD_NODE *) node->data;
instance= ((GUARD_NODE *) node->data)->instance;
process_instance(instance, current_node, &guarded_instances, node);
node= node->next;
}
timeout.tv_sec= time(NULL) + monitoring_interval;
timeout.tv_nsec= 0;
/* check the loop predicate before sleeping */
if (!(shutdown_requested && (!(guarded_instances))))
thread_registry.cond_timedwait(&thread_info, &COND_guardian,
&LOCK_guardian, &timeout);
}
stopped= TRUE;
pthread_mutex_unlock(&LOCK_guardian);
/* now, when the Guardian is stopped we can stop the IM */
thread_registry.unregister_thread(&thread_info);
thread_registry.request_shutdown();
my_thread_end();
}
int Guardian_thread::is_stopped()
{
int var;
pthread_mutex_lock(&LOCK_guardian);
var= stopped;
pthread_mutex_unlock(&LOCK_guardian);
return var;
}
/*
Initialize the list of guarded instances: loop through the Instance_map and
add all of the instances, which don't have 'nonguarded' option specified.
SYNOPSYS
Guardian_thread::init()
NOTE: One should always lock guardian before calling this routine.
RETURN
0 - ok
1 - error occured
*/
int Guardian_thread::init()
{
Instance *instance;
Instance_map::Iterator iterator(instance_map);
instance_map->lock();
/* clear the list of guarded instances */
free_root(&alloc, MYF(0));
init_alloc_root(&alloc, MEM_ROOT_BLOCK_SIZE, 0);
guarded_instances= NULL;
while ((instance= iterator.next()))
{
if (!(instance->options.nonguarded))
if (guard(instance, TRUE)) /* do not lock guardian */
{
instance_map->unlock();
return 1;
}
}
instance_map->unlock();
return 0;
}
/*
Add instance to the Guardian list
SYNOPSYS
guard()
instance the instance to be guarded
nolock whether we prefer do not lock Guardian here,
but use external locking instead
DESCRIPTION
The instance is added to the guarded instances list. Usually guard() is
called after we start an instance.
RETURN
0 - ok
1 - error occured
*/
int Guardian_thread::guard(Instance *instance, bool nolock)
{
LIST *node;
GUARD_NODE *content;
node= (LIST *) alloc_root(&alloc, sizeof(LIST));
content= (GUARD_NODE *) alloc_root(&alloc, sizeof(GUARD_NODE));
if ((!(node)) || (!(content)))
return 1;
/* we store the pointers to instances from the instance_map's MEM_ROOT */
content->instance= instance;
content->restart_counter= 0;
content->crash_moment= 0;
content->state= NOT_STARTED;
node->data= (void*) content;
if (nolock)
guarded_instances= list_add(guarded_instances, node);
else
{
pthread_mutex_lock(&LOCK_guardian);
guarded_instances= list_add(guarded_instances, node);
pthread_mutex_unlock(&LOCK_guardian);
}
return 0;
}
/*
TODO: perhaps it would make sense to create a pool of the LIST nodeents
and give them upon request. Now we are loosing a bit of memory when
guarded instance was stopped and then restarted (since we cannot free just
a piece of the MEM_ROOT).
*/
int Guardian_thread::stop_guard(Instance *instance)
{
LIST *node;
pthread_mutex_lock(&LOCK_guardian);
node= guarded_instances;
while (node != NULL)
{
/*
We compare only pointers, as we always use pointers from the
instance_map's MEM_ROOT.
*/
if (((GUARD_NODE *) node->data)->instance == instance)
{
guarded_instances= list_delete(guarded_instances, node);
pthread_mutex_unlock(&LOCK_guardian);
return 0;
}
else
node= node->next;
}
pthread_mutex_unlock(&LOCK_guardian);
/* if there is nothing to delete it is also fine */
return 0;
}
/*
An internal method which is called at shutdown to unregister instances and
attempt to stop them if requested.
SYNOPSYS
stop_instances()
stop_instances_arg whether we should stop instances at shutdown
DESCRIPTION
Loops through the guarded_instances list and prepares them for shutdown.
If stop_instances was requested, we need to issue a stop command and change
the state accordingly. Otherwise we simply delete an entry.
NOTE
Guardian object should be locked by the calling function.
RETURN
0 - ok
1 - error occured
*/
int Guardian_thread::stop_instances(bool stop_instances_arg)
{
LIST *node;
node= guarded_instances;
while (node != NULL)
{
if (!stop_instances_arg)
{
/* just forget about an instance */
guarded_instances= list_delete(guarded_instances, node);
/*
This should still work fine, as we have only removed the
node from the list. The pointer to the next one is still valid
*/
node= node->next;
}
else
{
GUARD_NODE *current_node= (GUARD_NODE *) node->data;
/*
If instance is running or was running (and now probably hanging),
request stop.
*/
if (current_node->instance->is_running() ||
(current_node->state == STARTED))
{
current_node->state= STOPPING;
current_node->last_checked= time(NULL);
}
else
/* otherwise remove it from the list */
guarded_instances= list_delete(guarded_instances, node);
/* But try to kill it anyway. Just in case */
current_node->instance->kill_instance(SIGTERM);
node= node->next;
}
}
return 0;
}
void Guardian_thread::lock()
{
pthread_mutex_lock(&LOCK_guardian);
}
void Guardian_thread::unlock()
{
pthread_mutex_unlock(&LOCK_guardian);
}