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MaxScale/server/core/server.cc
Esa Korhonen 7f978f275f MXS-2223 Log a message when a slave is discriminated due to replication lag 
Both the replication lag and the message printing state are saved in SERVER,
although the values are mostly used by readwritesplit. A log message is printed
both when a server goes over the limit and when it comes back below.
Because of concurrency issues, a message may be printed multiple times before
different threads detect the new message state.

Documentation updated to explain the change.
2019-01-21 13:02:18 +02:00

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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file server.c - A representation of a backend server within the gateway.
*
*/
#include "internal/server.hh"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string>
#include <list>
#include <mutex>
#include <sstream>
#include <mutex>
#include <maxbase/atomic.hh>
#include <maxbase/stopwatch.hh>
#include <maxscale/config.h>
#include <maxscale/service.h>
#include <maxscale/session.h>
#include <maxscale/dcb.h>
#include <maxscale/poll.h>
#include <maxscale/log.h>
#include <maxscale/ssl.h>
#include <maxscale/alloc.h>
#include <maxscale/paths.h>
#include <maxscale/utils.h>
#include <maxscale/json_api.h>
#include <maxscale/clock.h>
#include <maxscale/http.hh>
#include <maxscale/maxscale.h>
#include <maxscale/server.hh>
#include <maxscale/routingworker.hh>
#include "internal/monitor.h"
#include "internal/poll.hh"
#include "internal/config.hh"
#include "internal/service.hh"
#include "internal/modules.h"
using maxbase::Worker;
using maxscale::RoutingWorker;
using std::string;
using Guard = std::lock_guard<std::mutex>;
/** The latin1 charset */
#define SERVER_DEFAULT_CHARSET 0x08
const char CN_MONITORPW[] = "monitorpw";
const char CN_MONITORUSER[] = "monitoruser";
const char CN_PERSISTMAXTIME[] = "persistmaxtime";
const char CN_PERSISTPOOLMAX[] = "persistpoolmax";
const char CN_PROXY_PROTOCOL[] = "proxy_protocol";
static std::mutex server_lock;
static std::list<Server*> all_servers;
static const char ERR_CANNOT_MODIFY[] = "The server is monitored, so only the maintenance status can be "
"set/cleared manually. Status was not modified.";
static const char WRN_REQUEST_OVERWRITTEN[] = "Previous maintenance request was not yet read by the monitor "
"and was overwritten.";
static void server_parameter_free(SERVER_PARAM* tofree);
SERVER* server_alloc(const char* name, MXS_CONFIG_PARAMETER* params)
{
const char* monuser = config_get_string(params, CN_MONITORUSER);
const char* monpw = config_get_string(params, CN_MONITORPW);
if ((*monuser != '\0') != (*monpw != '\0'))
{
MXS_ERROR("Both '%s' and '%s' need to be defined for server '%s'",
CN_MONITORUSER,
CN_MONITORPW,
name);
return NULL;
}
const char* protocol = config_get_string(params, CN_PROTOCOL);
const char* authenticator = config_get_string(params, CN_AUTHENTICATOR);
if (!authenticator[0] && !(authenticator = get_default_authenticator(protocol)))
{
MXS_ERROR("No authenticator defined for server '%s' and no default "
"authenticator for protocol '%s'.",
name,
protocol);
return NULL;
}
void* auth_instance = NULL;
// Backend authenticators do not have options.
if (!authenticator_init(&auth_instance, authenticator, NULL))
{
MXS_ERROR("Failed to initialize authenticator module '%s' for server '%s' ",
authenticator,
name);
return NULL;
}
SSL_LISTENER* ssl = NULL;
if (!config_create_ssl(name, params, false, &ssl))
{
MXS_ERROR("Unable to initialize SSL for server '%s'", name);
return NULL;
}
Server* server = new(std::nothrow) Server;
char* my_name = MXS_STRDUP(name);
char* my_protocol = MXS_STRDUP(protocol);
char* my_authenticator = MXS_STRDUP(authenticator);
DCB** persistent = (DCB**)MXS_CALLOC(config_threadcount(), sizeof(*persistent));
if (!server || !my_name || !my_protocol || !my_authenticator || !persistent)
{
delete server;
MXS_FREE(my_name);
MXS_FREE(persistent);
MXS_FREE(my_protocol);
MXS_FREE(my_authenticator);
SSL_LISTENER_free(ssl);
return NULL;
}
const char* address = config_get_string(params, CN_ADDRESS);
if (snprintf(server->address, sizeof(server->address), "%s", address) > (int)sizeof(server->address))
{
MXS_WARNING("Truncated server address '%s' to the maximum size of %lu characters.",
address,
sizeof(server->address));
}
server->name = my_name;
server->port = config_get_integer(params, CN_PORT);
server->extra_port = config_get_integer(params, CN_EXTRA_PORT);
server->protocol = my_protocol;
server->authenticator = my_authenticator;
server->monuser[0] = '\0';
server->monpw[0] = '\0';
server->persistpoolmax = config_get_integer(params, CN_PERSISTPOOLMAX);
server->persistmaxtime = config_get_integer(params, CN_PERSISTMAXTIME);
server->proxy_protocol = config_get_bool(params, CN_PROXY_PROTOCOL);
server->parameters = NULL;
server->is_active = true;
server->auth_instance = auth_instance;
server->server_ssl = ssl;
server->persistent = persistent;
server->charset = SERVER_DEFAULT_CHARSET;
memset(&server->stats, 0, sizeof(server->stats));
server->persistmax = 0;
server->last_event = SERVER_UP_EVENT;
server->triggered_at = 0;
server->status = SERVER_RUNNING;
server->maint_request = MAINTENANCE_NO_CHANGE;
memset(server->version_string, '\0', MAX_SERVER_VERSION_LEN);
server->version = 0;
server->server_type = SERVER_TYPE_MARIADB;
server->node_id = -1;
server->rlag = MXS_RLAG_UNDEFINED;
server->node_ts = 0;
server->master_id = -1;
server->master_err_is_logged = false;
server->warn_ssl_not_enabled = true;
server->rlag_state = RLAG_NONE;
server->disk_space_threshold = NULL;
if (*monuser && *monpw)
{
server_add_mon_user(server, monuser, monpw);
}
for (MXS_CONFIG_PARAMETER* p = params; p; p = p->next)
{
server_set_parameter(server, p->name, p->value);
}
Guard guard(server_lock);
// This keeps the order of the servers the same as in 2.2
all_servers.push_front(server);
return server;
}
/**
* Deallocate the specified server
*
* @param server The service to deallocate
* @return Returns true if the server was freed
*/
void server_free(Server* server)
{
mxb_assert(server);
{
Guard guard(server_lock);
auto it = std::find(all_servers.begin(), all_servers.end(), server);
mxb_assert(it != all_servers.end());
all_servers.erase(it);
}
/* Clean up session and free the memory */
MXS_FREE(server->protocol);
MXS_FREE(server->name);
MXS_FREE(server->authenticator);
server_parameter_free(server->parameters);
if (server->persistent)
{
int nthr = config_threadcount();
for (int i = 0; i < nthr; i++)
{
dcb_persistent_clean_count(server->persistent[i], i, true);
}
MXS_FREE(server->persistent);
}
delete server->disk_space_threshold;
delete server;
}
/**
* Get a DCB from the persistent connection pool, if possible
*
* @param server The server to set the name on
* @param user The name of the user needing the connection
* @param ip Client IP address
* @param protocol The name of the protocol needed for the connection
* @param id Thread ID
*
* @return A DCB or NULL if no connection is found
*/
DCB* server_get_persistent(SERVER* server, const char* user, const char* ip, const char* protocol, int id)
{
DCB* dcb, * previous = NULL;
if (server->persistent[id]
&& dcb_persistent_clean_count(server->persistent[id], id, false)
&& server->persistent[id] // Check after cleaning
&& (server->status & SERVER_RUNNING))
{
dcb = server->persistent[id];
while (dcb)
{
if (dcb->user
&& dcb->protoname
&& dcb->remote
&& ip
&& !dcb->dcb_errhandle_called
&& !(dcb->flags & DCBF_HUNG)
&& 0 == strcmp(dcb->user, user)
&& 0 == strcmp(dcb->remote, ip)
&& 0 == strcmp(dcb->protoname, protocol))
{
if (NULL == previous)
{
server->persistent[id] = dcb->nextpersistent;
}
else
{
previous->nextpersistent = dcb->nextpersistent;
}
MXS_FREE(dcb->user);
dcb->user = NULL;
mxb::atomic::add(&server->stats.n_persistent, -1);
mxb::atomic::add(&server->stats.n_current, 1, mxb::atomic::RELAXED);
return dcb;
}
else
{
MXS_DEBUG("%lu [server_get_persistent] Rejected dcb "
"%p from pool, user %s looking for %s, protocol %s "
"looking for %s, hung flag %s, error handle called %s.",
pthread_self(),
dcb,
dcb->user ? dcb->user : "NULL",
user,
dcb->protoname ? dcb->protoname : "NULL",
protocol,
(dcb->flags & DCBF_HUNG) ? "true" : "false",
dcb->dcb_errhandle_called ? "true" : "false");
}
previous = dcb;
dcb = dcb->nextpersistent;
}
}
return NULL;
}
/**
* @brief Find a server with the specified name
*
* @param name Name of the server
* @return The server or NULL if not found
*/
SERVER* server_find_by_unique_name(const char* name)
{
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server->is_active && strcmp(server->name, name) == 0)
{
return server;
}
}
return nullptr;
}
/**
* Find several servers with the names specified in an array with a given size.
* The returned array (but not the elements) should be freed by the caller.
* If no valid server names were found or in case of error, nothing is written
* to the output parameter.
*
* @param servers An array of server names
* @param size Number of elements in the input server names array, equal to output
* size if any servers are found.
* @param output Where to save the output. Contains null elements for invalid server
* names. If all were invalid, the output is left untouched.
* @return Number of valid server names found
*/
int server_find_by_unique_names(char** server_names, int size, SERVER*** output)
{
mxb_assert(server_names && (size > 0));
SERVER** results = (SERVER**)MXS_CALLOC(size, sizeof(SERVER*));
if (!results)
{
return 0;
}
int found = 0;
for (int i = 0; i < size; i++)
{
results[i] = server_find_by_unique_name(server_names[i]);
found += (results[i]) ? 1 : 0;
}
if (found)
{
*output = results;
}
else
{
MXS_FREE(results);
}
return found;
}
/**
* Find an existing server
*
* @param servname The Server name or address
* @param port The server port
* @return The server or NULL if not found
*/
SERVER* server_find(const char* servname, unsigned short port)
{
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server->is_active && strcmp(server->address, servname) == 0 && server->port == port)
{
return server;
}
}
return nullptr;
}
/**
* Print details of an individual server
*
* @param server Server to print
*/
void printServer(const SERVER* server)
{
printf("Server %p\n", server);
printf("\tServer: %s\n", server->address);
printf("\tProtocol: %s\n", server->protocol);
printf("\tPort: %d\n", server->port);
printf("\tTotal connections: %d\n", server->stats.n_connections);
printf("\tCurrent connections: %d\n", server->stats.n_current);
printf("\tPersistent connections: %d\n", server->stats.n_persistent);
printf("\tPersistent actual max: %d\n", server->persistmax);
}
/**
* Print all servers
*
* Designed to be called within a debugger session in order
* to display all active servers within the gateway
*/
void printAllServers()
{
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server->is_active)
{
printServer(server);
}
}
}
/**
* Print all servers to a DCB
*
* Designed to be called within a debugger session in order
* to display all active servers within the gateway
*/
void dprintAllServers(DCB* dcb)
{
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server->is_active)
{
dprintServer(dcb, server);
}
}
}
/**
* Print all servers in Json format to a DCB
*/
void dprintAllServersJson(DCB* dcb)
{
json_t* all_servers_json = server_list_to_json("");
char* dump = json_dumps(all_servers_json, JSON_INDENT(4));
dcb_printf(dcb, "%s", dump);
MXS_FREE(dump);
json_decref(all_servers_json);
}
/**
* A class for cleaning up persistent connections
*/
class CleanupTask : public Worker::Task
{
public:
CleanupTask(const SERVER* server)
: m_server(server)
{
}
void execute(Worker& worker)
{
RoutingWorker& rworker = static_cast<RoutingWorker&>(worker);
mxb_assert(&rworker == RoutingWorker::get_current());
int thread_id = rworker.id();
dcb_persistent_clean_count(m_server->persistent[thread_id], thread_id, false);
}
private:
const SERVER* m_server; /**< Server to clean up */
};
/**
* @brief Clean up any stale persistent connections
*
* This function purges any stale persistent connections from @c server.
*
* @param server Server to clean up
*/
static void cleanup_persistent_connections(const SERVER* server)
{
CleanupTask task(server);
RoutingWorker::execute_concurrently(task);
}
/**
* Print server details to a DCB
*
* Designed to be called within a debugger session in order
* to display all active servers within the gateway
*/
void dprintServer(DCB* dcb, const SERVER* srv)
{
if (!server_is_active(srv))
{
return;
}
const Server* server = static_cast<const Server*>(srv);
dcb_printf(dcb, "Server %p (%s)\n", server, server->name);
dcb_printf(dcb, "\tServer: %s\n", server->address);
char* stat = server_status(server);
dcb_printf(dcb, "\tStatus: %s\n", stat);
MXS_FREE(stat);
dcb_printf(dcb, "\tProtocol: %s\n", server->protocol);
dcb_printf(dcb, "\tPort: %d\n", server->port);
dcb_printf(dcb, "\tServer Version: %s\n", server->version_string);
dcb_printf(dcb, "\tNode Id: %ld\n", server->node_id);
dcb_printf(dcb, "\tMaster Id: %ld\n", server->master_id);
dcb_printf(dcb,
"\tLast event: %s\n",
mon_get_event_name((mxs_monitor_event_t)server->last_event));
time_t t = maxscale_started() + MXS_CLOCK_TO_SEC(server->triggered_at);
dcb_printf(dcb, "\tTriggered at: %s\n", http_to_date(t).c_str());
if (server_is_slave(server) || server_is_relay(server))
{
if (server->rlag >= 0)
{
dcb_printf(dcb, "\tSlave delay: %d\n", server->rlag);
}
}
if (server->node_ts > 0)
{
struct tm result;
char buf[40];
dcb_printf(dcb,
"\tLast Repl Heartbeat: %s",
asctime_r(localtime_r((time_t*)(&server->node_ts), &result), buf));
}
SERVER_PARAM* param;
if ((param = server->parameters))
{
dcb_printf(dcb, "\tServer Parameters:\n");
while (param)
{
if (param->active)
{
dcb_printf(dcb,
"\t %s\t%s\n",
param->name,
param->value);
}
param = param->next;
}
}
dcb_printf(dcb, "\tNumber of connections: %d\n", server->stats.n_connections);
dcb_printf(dcb, "\tCurrent no. of conns: %d\n", server->stats.n_current);
dcb_printf(dcb, "\tCurrent no. of operations: %d\n", server->stats.n_current_ops);
dcb_printf(dcb, "\tNumber of routed packets: %lu\n", server->stats.packets);
std::ostringstream ave_os;
if (server_response_time_num_samples(server))
{
maxbase::Duration dur(server_response_time_average(server));
ave_os << dur;
}
else
{
ave_os << "not available";
}
dcb_printf(dcb, "\tAdaptive avg. select time: %s\n", ave_os.str().c_str());
if (server->persistpoolmax)
{
dcb_printf(dcb, "\tPersistent pool size: %d\n", server->stats.n_persistent);
cleanup_persistent_connections(server);
dcb_printf(dcb, "\tPersistent measured pool size: %d\n", server->stats.n_persistent);
dcb_printf(dcb, "\tPersistent actual size max: %d\n", server->persistmax);
dcb_printf(dcb, "\tPersistent pool size limit: %ld\n", server->persistpoolmax);
dcb_printf(dcb, "\tPersistent max time (secs): %ld\n", server->persistmaxtime);
dcb_printf(dcb, "\tConnections taken from pool: %lu\n", server->stats.n_from_pool);
double d = (double)server->stats.n_from_pool / (double)(server->stats.n_connections
+ server->stats.n_from_pool + 1);
dcb_printf(dcb, "\tPool availability: %0.2lf%%\n", d * 100.0);
}
if (server->server_ssl)
{
SSL_LISTENER* l = server->server_ssl;
dcb_printf(dcb,
"\tSSL initialized: %s\n",
l->ssl_init_done ? "yes" : "no");
dcb_printf(dcb,
"\tSSL method type: %s\n",
ssl_method_type_to_string(l->ssl_method_type));
dcb_printf(dcb, "\tSSL certificate verification depth: %d\n", l->ssl_cert_verify_depth);
dcb_printf(dcb, "\tSSL peer verification : %s\n", l->ssl_verify_peer_certificate ? "true" : "false");
dcb_printf(dcb,
"\tSSL certificate: %s\n",
l->ssl_cert ? l->ssl_cert : "null");
dcb_printf(dcb,
"\tSSL key: %s\n",
l->ssl_key ? l->ssl_key : "null");
dcb_printf(dcb,
"\tSSL CA certificate: %s\n",
l->ssl_ca_cert ? l->ssl_ca_cert : "null");
}
if (server->proxy_protocol)
{
dcb_printf(dcb, "\tPROXY protocol: on.\n");
}
}
/**
* Diagnostic to print number of DCBs in persistent pool for a server
*
* @param pdcb DCB to print results to
* @param server SERVER for which DCBs are to be printed
*/
void dprintPersistentDCBs(DCB* pdcb, const SERVER* server)
{
dcb_printf(pdcb, "Number of persistent DCBs: %d\n", server->stats.n_persistent);
}
/**
* List all servers in a tabular form to a DCB
*
*/
void dListServers(DCB* dcb)
{
Guard guard(server_lock);
bool have_servers = std::any_of(all_servers.begin(),
all_servers.end(),
[](Server* s) {
return s->is_active;
});
if (have_servers)
{
dcb_printf(dcb, "Servers.\n");
dcb_printf(dcb, "-------------------+-----------------+-------+-------------+--------------------\n");
dcb_printf(dcb,
"%-18s | %-15s | Port | Connections | %-20s\n",
"Server",
"Address",
"Status");
dcb_printf(dcb, "-------------------+-----------------+-------+-------------+--------------------\n");
for (Server* server : all_servers)
{
if (server->is_active)
{
char* stat = server_status(server);
dcb_printf(dcb,
"%-18s | %-15s | %5d | %11d | %s\n",
server->name,
server->address,
server->port,
server->stats.n_current,
stat);
MXS_FREE(stat);
}
}
dcb_printf(dcb, "-------------------+-----------------+-------+-------------+--------------------\n");
}
}
/**
* Convert a set of server status flags to a string, the returned
* string has been malloc'd and must be free'd by the caller
*
* @param server The server to return the status of
* @return A string representation of the status flags
*/
char* server_status(const SERVER* server)
{
mxb_assert(server);
uint64_t server_status = server->status;
string result;
string separator;
// Helper function.
auto concatenate_if = [&result, &separator](bool condition, const string& desc) {
if (condition)
{
result += separator + desc;
separator = ", ";
}
};
// TODO: The following values should be revisited at some point, but since they are printed by
// the REST API they should not be changed suddenly. Strictly speaking, even the combinations
// should not change, but this is more dependant on the monitors and have already changed.
const string maintenance = "Maintenance";
const string master = "Master";
const string relay = "Relay Master";
const string slave = "Slave";
const string synced = "Synced";
const string ndb = "NDB";
const string slave_ext = "Slave of External Server";
const string sticky = "Master Stickiness";
const string auth_err = "Auth Error";
const string running = "Running";
const string down = "Down";
// Maintenance is usually set by user so is printed first.
concatenate_if(status_is_in_maint(server_status), maintenance);
// Master cannot be a relay or a slave.
if (status_is_master(server_status))
{
concatenate_if(true, master);
}
else
{
// Relays are typically slaves as well. The binlog server may be an exception.
concatenate_if(status_is_relay(server_status), relay);
concatenate_if(status_is_slave(server_status), slave);
}
// The following Galera and Cluster bits may be combined with master/slave.
concatenate_if(status_is_joined(server_status), synced);
concatenate_if(status_is_ndb(server_status), ndb);
// May be combined with other MariaDB monitor flags.
concatenate_if(server_status & SERVER_SLAVE_OF_EXT_MASTER, slave_ext);
// Should this be printed only if server is master?
concatenate_if(server_status & SERVER_MASTER_STICKINESS, sticky);
concatenate_if(server_status & SERVER_AUTH_ERROR, auth_err);
concatenate_if(status_is_running(server_status), running);
concatenate_if(status_is_down(server_status), down);
return MXS_STRDUP(result.c_str());
}
/**
* Set a status bit in the server without locking
*
* @param server The server to update
* @param bit The bit to set for the server
*/
void server_set_status_nolock(SERVER* server, uint64_t bit)
{
server->status |= bit;
/** clear error logged flag before the next failure */
if (server_is_master(server))
{
server->master_err_is_logged = false;
}
}
/**
* Clears and sets specified bits.
*
* @attention This function does no locking
*
* @param server The server to update
* @param bits_to_clear The bits to clear for the server.
* @param bits_to_set The bits to set for the server.
*/
void server_clear_set_status_nolock(SERVER* server, uint64_t bits_to_clear, uint64_t bits_to_set)
{
/** clear error logged flag before the next failure */
if ((bits_to_set & SERVER_MASTER) && ((server->status & SERVER_MASTER) == 0))
{
server->master_err_is_logged = false;
}
if ((server->status & bits_to_clear) != bits_to_set)
{
server->status = (server->status & ~bits_to_clear) | bits_to_set;
}
}
/**
* Clear a status bit in the server without locking
*
* @param server The server to update
* @param bit The bit to clear for the server
*/
void server_clear_status_nolock(SERVER* server, uint64_t bit)
{
server->status &= ~bit;
}
/**
* Transfer status bitstring from one server to another
*
* @attention This function does no locking
*
* @param dest_server The server to be updated
* @param source_server The server to provide the new bit string
*/
void server_transfer_status(SERVER* dest_server, const SERVER* source_server)
{
dest_server->status = source_server->status;
}
/**
* Add a user name and password to use for monitoring the
* state of the server.
*
* @param server The server to update
* @param user The user name to use
* @param passwd The password of the user
*/
void server_add_mon_user(SERVER* server, const char* user, const char* passwd)
{
if (user != server->monuser
&& snprintf(server->monuser, sizeof(server->monuser), "%s", user) > (int)sizeof(server->monuser))
{
MXS_WARNING("Truncated monitor user for server '%s', maximum username "
"length is %lu characters.",
server->name,
sizeof(server->monuser));
}
if (passwd != server->monpw
&& snprintf(server->monpw, sizeof(server->monpw), "%s", passwd) > (int)sizeof(server->monpw))
{
MXS_WARNING("Truncated monitor password for server '%s', maximum password "
"length is %lu characters.",
server->name,
sizeof(server->monpw));
}
}
/**
* Check and update a server definition following a configuration
* update. Changes will not affect any current connections to this
* server, however all new connections will use the new settings.
*
* If the new settings are different from those already applied to the
* server then a message will be written to the log.
*
* @param server The server to update
* @param protocol The new protocol for the server
* @param user The monitor user for the server
* @param passwd The password to use for the monitor user
*/
void server_update_credentials(SERVER* server, const char* user, const char* passwd)
{
if (user != NULL && passwd != NULL)
{
server_add_mon_user(server, user, passwd);
}
}
static SERVER_PARAM* allocate_parameter(const char* name, const char* value)
{
char* my_name = MXS_STRDUP(name);
char* my_value = MXS_STRDUP(value);
SERVER_PARAM* param = (SERVER_PARAM*)MXS_MALLOC(sizeof(SERVER_PARAM));
if (!my_name || !my_value || !param)
{
MXS_FREE(my_name);
MXS_FREE(my_value);
MXS_FREE(param);
return NULL;
}
param->active = true;
param->name = my_name;
param->value = my_value;
return param;
}
bool server_remove_parameter(SERVER* srv, const char* name)
{
Server* server = static_cast<Server*>(srv);
bool rval = false;
std::lock_guard<std::mutex> guard(server->m_lock);
for (SERVER_PARAM* p = server->parameters; p; p = p->next)
{
if (strcmp(p->name, name) == 0 && p->active)
{
p->active = false;
rval = true;
break;
}
}
return rval;
}
void server_set_parameter(SERVER* srv, const char* name, const char* value)
{
Server* server = static_cast<Server*>(srv);
SERVER_PARAM* param = allocate_parameter(name, value);
if (param)
{
std::lock_guard<std::mutex> guard(server->m_lock);
// Insert new value
param->next = server->parameters;
server->parameters = param;
// Mark old value, if found, as inactive
for (SERVER_PARAM* p = server->parameters->next; p; p = p->next)
{
if (strcmp(p->name, name) == 0 && p->active)
{
p->active = false;
break;
}
}
}
}
/**
* Free a list of server parameters
* @param tofree Parameter list to free
*/
static void server_parameter_free(SERVER_PARAM* tofree)
{
SERVER_PARAM* param;
if (tofree)
{
param = tofree;
tofree = tofree->next;
MXS_FREE(param->name);
MXS_FREE(param->value);
MXS_FREE(param);
}
}
/**
* Same as server_get_parameter but doesn't lock the server
*
* @note Should only be called when the server is already locked
*/
static size_t server_get_parameter_nolock(const SERVER* server, const char* name, char* out, size_t size)
{
size_t len = 0;
SERVER_PARAM* param = server->parameters;
while (param)
{
if (strcmp(param->name, name) == 0 && param->active)
{
len = snprintf(out, out ? size : 0, "%s", param->value);
break;
}
param = param->next;
}
return len;
}
/**
* Retrieve a parameter value from a server
*
* @param server The server we are looking for a parameter of
* @param name The name of the parameter we require
* @param out Buffer where value is stored, use NULL to check if the parameter exists
* @param size Size of @c out, ignored if @c out is NULL
*
* @return Length of the parameter value or 0 if parameter was not found
*/
size_t server_get_parameter(const SERVER* srv, const char* name, char* out, size_t size)
{
const Server* server = static_cast<const Server*>(srv);
std::lock_guard<std::mutex> guard(server->m_lock);
return server_get_parameter_nolock(server, name, out, size);
}
/**
* Return a resultset that has the current set of servers in it
*
* @return A Result set
*/
std::unique_ptr<ResultSet> serverGetList()
{
std::unique_ptr<ResultSet> set =
ResultSet::create({"Server", "Address", "Port", "Connections", "Status"});
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server_is_active(server))
{
char* stat = server_status(server);
set->add_row({server->name, server->address, std::to_string(server->port),
std::to_string(server->stats.n_current), stat});
MXS_FREE(stat);
}
}
return set;
}
/*
* Update the address value of a specific server
*
* @param server The server to update
* @param address The new address
*
*/
void server_update_address(SERVER* server, const char* address)
{
Guard guard(server_lock);
if (server && address)
{
strcpy(server->address, address);
}
}
/*
* Update the port value of a specific server
*
* @param server The server to update
* @param port The new port value
*
*/
void server_update_port(SERVER* server, unsigned short port)
{
Guard guard(server_lock);
if (server && port > 0)
{
server->port = port;
}
}
/*
* Update the extra_port value of a specific server
*
* @param server The server to update
* @param port The new extra_port value
*
*/
void server_update_extra_port(SERVER* server, unsigned short port)
{
mxb::atomic::store(&server->extra_port, port, mxb::atomic::RELAXED);
}
static struct
{
const char* str;
uint64_t bit;
} ServerBits[] =
{
{"running", SERVER_RUNNING },
{"master", SERVER_MASTER },
{"slave", SERVER_SLAVE },
{"synced", SERVER_JOINED },
{"ndb", SERVER_NDB },
{"maintenance", SERVER_MAINT },
{"maint", SERVER_MAINT },
{"stale", SERVER_WAS_MASTER},
{NULL, 0 }
};
/**
* Map the server status bit
*
* @param str String representation
* @return bit value or 0 on error
*/
uint64_t server_map_status(const char* str)
{
int i;
for (i = 0; ServerBits[i].str; i++)
{
if (!strcasecmp(str, ServerBits[i].str))
{
return ServerBits[i].bit;
}
}
return 0;
}
/**
* Set the version string of the server.
*
* @param server Server to update
* @param version_string Version string
*/
void server_set_version_string(SERVER* server, const char* version_string)
{
// Possible data race. The string may be accessed while we are updating it.
// Take some precautions to ensure that the string cannot be completely garbled at any point.
// Strictly speaking, this is not fool-proof as writes may not appear in order to the reader.
size_t old_len = strlen(server->version_string);
size_t new_len = strlen(version_string);
if (new_len >= MAX_SERVER_VERSION_LEN)
{
new_len = MAX_SERVER_VERSION_LEN - 1;
}
if (new_len < old_len)
{
// If the new string is shorter, we start by nulling out the
// excess data.
memset(server->version_string + new_len, 0, old_len - new_len);
}
// No null-byte needs to be set. The array starts out as all zeros and the above memset adds
// the necessary null, should the new string be shorter than the old.
strncpy(server->version_string, version_string, new_len);
}
/**
* Set the version of the server.
*
* @param server Server to update
* @param version_string Human readable version string.
* @param version Version encoded as MariaDB encodes the version, i.e.:
* version = major * 10000 + minor * 100 + patch
*/
void server_set_version(SERVER* server, const char* version_string, uint64_t version)
{
server_set_version_string(server, version_string);
atomic_store_uint64(&server->version, version);
bool is_mariadb = (strcasestr(version_string, "mariadb") != NULL);
server->server_type = is_mariadb ? SERVER_TYPE_MARIADB : SERVER_TYPE_MYSQL;
}
uint64_t server_get_version(const SERVER* server)
{
return atomic_load_uint64(&server->version);
}
namespace
{
// Converts SERVER_PARAM to MXS_CONFIG_PARAM and keeps them in the same order
class ParamAdaptor
{
public:
ParamAdaptor(SERVER_PARAM* params)
{
for (auto p = params; p; p = p->next)
{
if (p->active)
{
// The current tail of the list
auto it = m_params.begin();
// Push the new tail
m_params.push_front({p->name, p->value, nullptr});
if (it != m_params.end())
{
// Update the old tail to point to the new tail
it->next = &m_params.front();
}
}
}
}
operator MXS_CONFIG_PARAMETER*()
{
// Return the head of the parameter list which is the tail of the internal list
return m_params.empty() ? nullptr : &m_params.back();
}
private:
// Holds the temporary configuration objects. Needs to be a list so that
// inserts into the container won't invalidate the next pointers
std::list<MXS_CONFIG_PARAMETER> m_params;
};
}
/**
* Creates a server configuration at the location pointed by @c filename
*
* @param server Server to serialize into a configuration
* @param filename Filename where configuration is written
* @return True on success, false on error
*/
static bool create_server_config(const SERVER* server, const char* filename)
{
int file = open(filename, O_EXCL | O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (file == -1)
{
MXS_ERROR("Failed to open file '%s' when serializing server '%s': %d, %s",
filename,
server->name,
errno,
mxs_strerror(errno));
return false;
}
// TODO: Check for return values on all of the dprintf calls
dprintf(file, "[%s]\n", server->name);
dprintf(file, "%s=server\n", CN_TYPE);
const MXS_MODULE* mod = get_module(server->protocol, MODULE_PROTOCOL);
dump_param_list(file,
ParamAdaptor(server->parameters),
{CN_TYPE},
config_server_params,
mod->parameters);
std::unordered_set<std::string> known;
for (auto a : {config_server_params, mod->parameters})
{
for (int i = 0; a[i].name; i++)
{
known.insert(a[i].name);
}
}
for (auto p = server->parameters; p; p = p->next)
{
if (known.count(p->name) == 0 && p->active)
{
dprintf(file, "%s=%s\n", p->name, p->value);
}
}
close(file);
return true;
}
bool server_serialize(const SERVER* server)
{
bool rval = false;
char filename[PATH_MAX];
snprintf(filename,
sizeof(filename),
"%s/%s.cnf.tmp",
get_config_persistdir(),
server->name);
if (unlink(filename) == -1 && errno != ENOENT)
{
MXS_ERROR("Failed to remove temporary server configuration at '%s': %d, %s",
filename,
errno,
mxs_strerror(errno));
}
else if (create_server_config(server, filename))
{
char final_filename[PATH_MAX];
strcpy(final_filename, filename);
char* dot = strrchr(final_filename, '.');
mxb_assert(dot);
*dot = '\0';
if (rename(filename, final_filename) == 0)
{
rval = true;
}
else
{
MXS_ERROR("Failed to rename temporary server configuration at '%s': %d, %s",
filename,
errno,
mxs_strerror(errno));
}
}
return rval;
}
/**
* Set a status bit in the server under a lock. This ensures synchronization
* with the server monitor thread. Calling this inside the monitor will likely
* cause a deadlock. If the server is monitored, only set the pending bit.
*
* @param server The server to update
* @param bit The bit to set for the server
*/
bool mxs::server_set_status(SERVER* srv, int bit, string* errmsg_out)
{
Server* server = static_cast<Server*>(srv);
bool written = false;
/* First check if the server is monitored. This isn't done under a lock
* but the race condition cannot cause significant harm. Monitors are never
* freed so the pointer stays valid. */
MXS_MONITOR* mon = monitor_server_in_use(server);
std::lock_guard<std::mutex> guard(server->m_lock);
if (mon && mon->state == MONITOR_STATE_RUNNING)
{
/* This server is monitored, in which case modifying any other status bit than Maintenance is
* disallowed. Maintenance is set/cleared using a special variable which the monitor reads when
* starting the next update cycle. Also set a flag so the next loop happens sooner. */
if (bit & ~SERVER_MAINT)
{
MXS_ERROR(ERR_CANNOT_MODIFY);
if (errmsg_out)
{
*errmsg_out = ERR_CANNOT_MODIFY;
}
}
else if (bit & SERVER_MAINT)
{
// Warn if the previous request hasn't been read.
int previous_request = atomic_exchange_int(&server->maint_request, MAINTENANCE_ON);
written = true;
if (previous_request != MAINTENANCE_NO_CHANGE)
{
MXS_WARNING(WRN_REQUEST_OVERWRITTEN);
}
atomic_store_int(&mon->check_maintenance_flag, MAINTENANCE_FLAG_CHECK);
}
}
else
{
/* Set the bit directly */
server_set_status_nolock(server, bit);
written = true;
}
return written;
}
/**
* Clear a status bit in the server under a lock. This ensures synchronization
* with the server monitor thread. Calling this inside the monitor will likely
* cause a deadlock. If the server is monitored, only clear the pending bit.
*
* @param server The server to update
* @param bit The bit to clear for the server
*/
bool mxs::server_clear_status(SERVER* srv, int bit, string* errmsg_out)
{
Server* server = static_cast<Server*>(srv);
bool written = false;
MXS_MONITOR* mon = monitor_server_in_use(server);
std::lock_guard<std::mutex> guard(server->m_lock);
if (mon && mon->state == MONITOR_STATE_RUNNING)
{
// See server_set_status().
if (bit & ~SERVER_MAINT)
{
MXS_ERROR(ERR_CANNOT_MODIFY);
if (errmsg_out)
{
*errmsg_out = ERR_CANNOT_MODIFY;
}
}
else if (bit & SERVER_MAINT)
{
// Warn if the previous request hasn't been read.
int previous_request = atomic_exchange_int(&server->maint_request, MAINTENANCE_OFF);
written = true;
if (previous_request != MAINTENANCE_NO_CHANGE)
{
MXS_WARNING(WRN_REQUEST_OVERWRITTEN);
}
atomic_store_int(&mon->check_maintenance_flag, MAINTENANCE_FLAG_CHECK);
}
}
else
{
/* Clear bit directly */
server_clear_status_nolock(server, bit);
written = true;
}
return written;
}
bool server_is_mxs_service(const SERVER* server)
{
bool rval = false;
/** Do a coarse check for local server pointing to a MaxScale service */
if (strcmp(server->address, "127.0.0.1") == 0
|| strcmp(server->address, "::1") == 0
|| strcmp(server->address, "localhost") == 0
|| strcmp(server->address, "localhost.localdomain") == 0)
{
if (service_port_is_used(server->port))
{
rval = true;
}
}
return rval;
}
static json_t* server_json_attributes(const SERVER* server)
{
/** Resource attributes */
json_t* attr = json_object();
/** Store server parameters in attributes */
json_t* params = json_object();
const MXS_MODULE* mod = get_module(server->protocol, MODULE_PROTOCOL);
config_add_module_params_json(ParamAdaptor(server->parameters),
{CN_TYPE},
config_server_params,
mod->parameters,
params);
// Add weighting parameters that weren't added by config_add_module_params_json
for (SERVER_PARAM* p = server->parameters; p; p = p->next)
{
if (!json_object_get(params, p->name))
{
json_object_set_new(params, p->name, json_string(p->value));
}
}
json_object_set_new(attr, CN_PARAMETERS, params);
/** Store general information about the server state */
char* stat = server_status(server);
json_object_set_new(attr, CN_STATE, json_string(stat));
MXS_FREE(stat);
json_object_set_new(attr, CN_VERSION_STRING, json_string(server->version_string));
json_object_set_new(attr, "node_id", json_integer(server->node_id));
json_object_set_new(attr, "master_id", json_integer(server->master_id));
const char* event_name = mon_get_event_name((mxs_monitor_event_t)server->last_event);
time_t t = maxscale_started() + MXS_CLOCK_TO_SEC(server->triggered_at);
json_object_set_new(attr, "last_event", json_string(event_name));
json_object_set_new(attr, "triggered_at", json_string(http_to_date(t).c_str()));
if (server->rlag >= 0)
{
json_object_set_new(attr, "replication_lag", json_integer(server->rlag));
}
if (server->node_ts > 0)
{
struct tm result;
char timebuf[30];
time_t tim = server->node_ts;
asctime_r(localtime_r(&tim, &result), timebuf);
trim(timebuf);
json_object_set_new(attr, "last_heartbeat", json_string(timebuf));
}
/** Store statistics */
json_t* stats = json_object();
json_object_set_new(stats, "connections", json_integer(server->stats.n_current));
json_object_set_new(stats, "total_connections", json_integer(server->stats.n_connections));
json_object_set_new(stats, "persistent_connections", json_integer(server->stats.n_persistent));
json_object_set_new(stats, "active_operations", json_integer(server->stats.n_current_ops));
json_object_set_new(stats, "routed_packets", json_integer(server->stats.packets));
maxbase::Duration response_ave(server_response_time_average(server));
json_object_set_new(stats, "adaptive_avg_select_time", json_string(to_string(response_ave).c_str()));
json_object_set_new(attr, "statistics", stats);
return attr;
}
static json_t* server_to_json_data(const SERVER* server, const char* host)
{
json_t* rval = json_object();
/** Add resource identifiers */
json_object_set_new(rval, CN_ID, json_string(server->name));
json_object_set_new(rval, CN_TYPE, json_string(CN_SERVERS));
/** Relationships */
json_t* rel = json_object();
json_t* service_rel = service_relations_to_server(server, host);
json_t* monitor_rel = monitor_relations_to_server(server, host);
if (service_rel)
{
json_object_set_new(rel, CN_SERVICES, service_rel);
}
if (monitor_rel)
{
json_object_set_new(rel, CN_MONITORS, monitor_rel);
}
json_object_set_new(rval, CN_RELATIONSHIPS, rel);
/** Attributes */
json_object_set_new(rval, CN_ATTRIBUTES, server_json_attributes(server));
json_object_set_new(rval, CN_LINKS, mxs_json_self_link(host, CN_SERVERS, server->name));
return rval;
}
json_t* server_to_json(const SERVER* server, const char* host)
{
string self = MXS_JSON_API_SERVERS;
self += server->name;
return mxs_json_resource(host, self.c_str(), server_to_json_data(server, host));
}
json_t* server_list_to_json(const char* host)
{
json_t* data = json_array();
Guard guard(server_lock);
for (Server* server : all_servers)
{
if (server_is_active(server))
{
json_array_append_new(data, server_to_json_data(server, host));
}
}
return mxs_json_resource(host, MXS_JSON_API_SERVERS, data);
}
bool server_set_disk_space_threshold(SERVER* server, const char* disk_space_threshold)
{
bool rv = false;
MxsDiskSpaceThreshold dst;
rv = config_parse_disk_space_threshold(&dst, disk_space_threshold);
if (rv)
{
if (!server->disk_space_threshold)
{
server->disk_space_threshold = new(std::nothrow) MxsDiskSpaceThreshold;
}
if (server->disk_space_threshold)
{
server->disk_space_threshold->swap(dst);
}
else
{
rv = false;
}
}
return rv;
}
namespace
{
std::mutex ave_write_mutex;
}
void server_add_response_average(SERVER* srv, double ave, int num_samples)
{
Server* server = static_cast<Server*>(srv);
std::lock_guard<std::mutex> guard(ave_write_mutex);
server->response_time_add(ave, num_samples);
}
int server_response_time_num_samples(const SERVER* srv)
{
const Server* server = static_cast<const Server*>(srv);
return server->response_time_num_samples();
}
double server_response_time_average(const SERVER* srv)
{
const Server* server = static_cast<const Server*>(srv);
return server->response_time_average();
}
/** Apply backend average and adjust sample_max, which determines the weight of a new average
* applied to EMAverage.
* Sample max is raised if the server is fast, aggresively lowered if the incoming average is clearly
* lower than the EMA, else just lowered a bit. The normal increase and decrease, drifting, of the max
* is done to follow the speed of a server. The important part is the lowering of max, to allow for a
* server that is speeding up to be adjusted and used.
*
* Three new magic numbers to replace the sample max magic number...
*
*/
void Server::response_time_add(double ave, int num_samples)
{
constexpr double drift {1.1};
int current_max = m_response_time.sample_max();
int new_max {0};
// This server handles more samples than EMA max.
// Increasing max allows all servers to be fairly compared.
if (num_samples >= current_max)
{
new_max = num_samples * drift;
}
// This server is experiencing high load of some kind,
// lower max to give more weight to the samples.
else if (m_response_time.average() / ave > 2)
{
new_max = current_max * 0.5;
}
// Let the max slowly trickle down to keep
// the sample max close to reality.
else
{
new_max = current_max / drift;
}
m_response_time.set_sample_max(new_max);
m_response_time.add(ave, num_samples);
}
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