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/*
* Copyright (c) 2018 Balazs Scheidler
* Copyright (c) 2018 Balabit
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* As an additional exemption you are allowed to compile & link against the
* OpenSSL libraries as published by the OpenSSL project. See the file
* COPYING for details.
*
*/
#ifndef HTTP_LOADBALANCER_H_INCLUDED
#define HTTP_LOADBALANCER_H_INCLUDED 1
#include "template/templates.h"
typedef enum
{
HTTP_TARGET_OPERATIONAL,
HTTP_TARGET_FAILED
} HTTPLoadBalancerTargetState;
typedef struct _HTTPLoadBalancerTarget HTTPLoadBalancerTarget;
typedef struct _HTTPLoadBalancerClient HTTPLoadBalancerClient;
typedef struct _HTTPLoadBalancer HTTPLoadBalancer;
/* NOTE: this struct represents an actual HTTP target URL. The existence of
* this structure is ensured even in multi-threaded environments. Some of
* the members of the struct are read-only and are _always_ available
* without locking. Others are protected by the LoadBalancer's lock and
* should be manipulated under the protection of that lock.
*/
struct _HTTPLoadBalancerTarget
{
/* read-only data, no need to lock */
LogTemplate *url_template;
gint index;
/* read-write data, locking must be in effect */
HTTPLoadBalancerTargetState state;
gint number_of_clients;
gint max_clients;
time_t last_failure_time;
gchar formatted_index[16];
};
gboolean http_lb_target_is_url_templated(HTTPLoadBalancerTarget *self);
const gchar *http_lb_target_get_literal_url(HTTPLoadBalancerTarget *self);
void http_lb_target_format_templated_url(HTTPLoadBalancerTarget *self, LogMessage *msg,
const LogTemplateOptions *template_options, GString *result);
struct _HTTPLoadBalancerClient
{
HTTPLoadBalancerTarget *target;
};
void http_lb_client_init(HTTPLoadBalancerClient *, HTTPLoadBalancer *lb);
void http_lb_client_deinit(HTTPLoadBalancerClient *);
struct _HTTPLoadBalancer
{
GMutex lock;
HTTPLoadBalancerTarget *targets;
gint num_targets;
gint num_clients;
gint num_failed_targets;
gint recovery_timeout;
time_t last_recovery_attempt;
};
HTTPLoadBalancerTarget *http_load_balancer_choose_target(HTTPLoadBalancer *self, HTTPLoadBalancerClient *lbc);
gboolean http_load_balancer_add_target(HTTPLoadBalancer *self, const gchar *url, GError **error);
void http_load_balancer_drop_all_targets(HTTPLoadBalancer *self);
void http_load_balancer_track_client(HTTPLoadBalancer *self, HTTPLoadBalancerClient *lbc);
void http_load_balancer_set_target_failed(HTTPLoadBalancer *self, HTTPLoadBalancerTarget *target);
void http_load_balancer_set_target_successful(HTTPLoadBalancer *self, HTTPLoadBalancerTarget *target);
gboolean http_load_balancer_is_url_templated(HTTPLoadBalancer *self);
void http_load_balancer_set_recovery_timeout(HTTPLoadBalancer *self, gint recovery_timeout);
HTTPLoadBalancer *http_load_balancer_new(void);
void http_load_balancer_free(HTTPLoadBalancer *self);
#endif
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