add connection pool

HISTORY

 
-Version 1.06  2014-06-16
+Version 1.06  2014-06-17
   * update source code from FastDFS V5.02
   * add function short2buff and buff2short
   * add object memory pool (fast_mblock.h and fast_mblock.c)
@@ -8,6 +8,7 @@ Version 1.06  2014-06-16
     such as #include ../../conf/common.conf
   * add get_url_content_ex to support buffer passed by caller
   * logger can set rotate time format
+  * add connection pool
 
 Version 1.05  2012-07-08
   * update source code from FastDFS V3.09

src/connection_pool.c

+/**
+* Copyright (C) 2008 Happy Fish / YuQing
+*
+* FastDFS may be copied only under the terms of the GNU General
+* Public License V3, which may be found in the FastDFS source kit.
+* Please visit the FastDFS Home Page http://www.csource.org/ for more detail.
+**/
+
+#include <netdb.h>
+#include <unistd.h>
+#include <errno.h>
+#include "logger.h"
+#include "sockopt.h"
+#include "shared_func.h"
+#include "sched_thread.h"
+#include "connection_pool.h"
+
+int conn_pool_init(ConnectionPool *cp, int connect_timeout, \
+	const int max_count_per_entry, const int max_idle_time)
+{
+	int result;
+
+	if ((result=init_pthread_lock(&cp->lock)) != 0)
+	{
+		return result;
+	}
+	cp->connect_timeout = connect_timeout;
+	cp->max_count_per_entry = max_count_per_entry;
+	cp->max_idle_time = max_idle_time;
+
+	return hash_init(&(cp->hash_array), simple_hash, 1024, 0.75);
+}
+
+void conn_pool_destroy(ConnectionPool *cp)
+{
+	pthread_mutex_lock(&cp->lock);
+	hash_destroy(&(cp->hash_array));
+	pthread_mutex_unlock(&cp->lock);
+
+	pthread_mutex_destroy(&cp->lock);
+}
+
+void conn_pool_disconnect_server(ConnectionInfo *pConnection)
+{
+	if (pConnection->sock >= 0)
+	{
+		close(pConnection->sock);
+		pConnection->sock = -1;
+	}
+}
+
+int conn_pool_connect_server(ConnectionInfo *pConnection, \
+		const int connect_timeout)
+{
+	int result;
+
+	if (pConnection->sock >= 0)
+	{
+		close(pConnection->sock);
+	}
+
+	pConnection->sock = socket(AF_INET, SOCK_STREAM, 0);
+	if(pConnection->sock < 0)
+	{
+		logError("file: "__FILE__", line: %d, " \
+			"socket create failed, errno: %d, " \
+			"error info: %s", __LINE__, errno, STRERROR(errno));
+		return errno != 0 ? errno : EPERM;
+	}
+
+	if ((result=tcpsetnonblockopt(pConnection->sock)) != 0)
+	{
+		close(pConnection->sock);
+		pConnection->sock = -1;
+		return result;
+	}
+
+	if ((result=connectserverbyip_nb(pConnection->sock, \
+		pConnection->ip_addr, pConnection->port, \
+		connect_timeout)) != 0)
+	{
+		logError("file: "__FILE__", line: %d, " \
+			"connect to %s:%d fail, errno: %d, " \
+			"error info: %s", __LINE__, pConnection->ip_addr, \
+			pConnection->port, result, STRERROR(result));
+
+		close(pConnection->sock);
+		pConnection->sock = -1;
+		return result;
+	}
+
+	return 0;
+}
+
+static int conn_pool_get_key(const ConnectionInfo *conn, char *key, int *key_len)
+{
+	struct in_addr sin_addr;
+
+        if (inet_aton(conn->ip_addr, &sin_addr) == 0)
+        {
+		*key_len = 0;
+                return EINVAL;
+        }
+
+	int2buff(sin_addr.s_addr, key);
+	*key_len = 4 + sprintf(key + 4, "%d", conn->port);
+
+	return 0;
+}
+
+ConnectionInfo *conn_pool_get_connection(ConnectionPool *cp, 
+	const ConnectionInfo *conn, int *err_no)
+{
+	char key[32];
+	int key_len;
+	int bytes;
+	char *p;
+	ConnectionManager *cm;
+	ConnectionNode *node;
+	ConnectionInfo *ci;
+	time_t current_time;
+
+	*err_no = conn_pool_get_key(conn, key, &key_len);
+	if (*err_no != 0)
+	{
+		return NULL;
+	}
+
+	pthread_mutex_lock(&cp->lock);
+	cm = (ConnectionManager *)hash_find(&cp->hash_array, key, key_len);
+	if (cm == NULL)
+	{
+		cm = (ConnectionManager *)malloc(sizeof(ConnectionManager));
+		if (cm == NULL)
+		{
+			*err_no = errno != 0 ? errno : ENOMEM;
+			logError("file: "__FILE__", line: %d, " \
+				"malloc %d bytes fail, errno: %d, " \
+				"error info: %s", __LINE__, \
+				(int)sizeof(ConnectionManager), \
+				*err_no, STRERROR(*err_no));
+			pthread_mutex_unlock(&cp->lock);
+			return NULL;
+		}
+
+		cm->head = NULL;
+		cm->total_count = 0;
+		cm->free_count = 0;
+		if ((*err_no=init_pthread_lock(&cm->lock)) != 0)
+		{
+			pthread_mutex_unlock(&cp->lock);
+			return NULL;
+		}
+		hash_insert(&cp->hash_array, key, key_len, cm);
+	}
+	pthread_mutex_unlock(&cp->lock);
+
+	current_time = get_current_time();
+	pthread_mutex_lock(&cm->lock);
+	while (1)
+	{
+		if (cm->head == NULL)
+		{
+			if ((cp->max_count_per_entry > 0) && 
+				(cm->total_count >= cp->max_count_per_entry))
+			{
+				*err_no = ENOSPC;
+				logError("file: "__FILE__", line: %d, " \
+					"connections: %d of server %s:%d " \
+					"exceed limit: %d", __LINE__, \
+					cm->total_count, conn->ip_addr, \
+					conn->port, cp->max_count_per_entry);
+				pthread_mutex_unlock(&cm->lock);
+				return NULL;
+			}
+
+			bytes = sizeof(ConnectionInfo) + sizeof(ConnectionNode);
+			p = (char *)malloc(bytes);
+			if (p == NULL)
+			{
+				*err_no = errno != 0 ? errno : ENOMEM;
+				logError("file: "__FILE__", line: %d, " \
+					"malloc %d bytes fail, errno: %d, " \
+					"error info: %s", __LINE__, \
+					bytes, *err_no, STRERROR(*err_no));
+				pthread_mutex_unlock(&cm->lock);
+				return NULL;
+			}
+
+			node = (ConnectionNode *)(p + sizeof(ConnectionInfo));
+			node->conn = (ConnectionInfo *)p;
+			node->manager = cm;
+			node->next = NULL;
+			node->atime = 0;
+
+			cm->total_count++;
+			pthread_mutex_unlock(&cm->lock);
+
+			memcpy(node->conn, conn, sizeof(ConnectionInfo));
+			node->conn->sock = -1;
+			*err_no = conn_pool_connect_server(node->conn, \
+					cp->connect_timeout);
+			if (*err_no != 0)
+			{
+				free(p);
+				return NULL;
+			}
+
+			logDebug("file: "__FILE__", line: %d, " \
+				"server %s:%d, new connection: %d, " \
+				"total_count: %d, free_count: %d",   \
+				__LINE__, conn->ip_addr, conn->port, \
+				node->conn->sock, cm->total_count, \
+				cm->free_count);
+			return node->conn;
+		}
+		else
+		{
+			node = cm->head;
+			ci = node->conn;
+			cm->head = node->next;
+			cm->free_count--;
+
+			if (current_time - node->atime > cp->max_idle_time)
+			{
+				cm->total_count--;
+
+				logDebug("file: "__FILE__", line: %d, " \
+					"server %s:%d, connection: %d idle " \
+					"time: %d exceeds max idle time: %d, "\
+					"total_count: %d, free_count: %d", \
+					__LINE__, conn->ip_addr, conn->port, \
+					ci->sock, \
+					(int)(current_time - node->atime), \
+					cp->max_idle_time, cm->total_count, \
+					cm->free_count);
+
+				conn_pool_disconnect_server(ci);
+				free(ci);
+				continue;
+			}
+
+			pthread_mutex_unlock(&cm->lock);
+			logDebug("file: "__FILE__", line: %d, " \
+				"server %s:%d, reuse connection: %d, " \
+				"total_count: %d, free_count: %d", 
+				__LINE__, conn->ip_addr, conn->port, 
+				ci->sock, cm->total_count, cm->free_count);
+			return ci;
+		}
+	}
+}
+
+int conn_pool_close_connection_ex(ConnectionPool *cp, ConnectionInfo *conn, 
+	const bool bForce)
+{
+	char key[32];
+	int result;
+	int key_len;
+	ConnectionManager *cm;
+	ConnectionNode *node;
+
+	result = conn_pool_get_key(conn, key, &key_len);
+	if (result != 0)
+	{
+		return result;
+	}
+
+	pthread_mutex_lock(&cp->lock);
+	cm = (ConnectionManager *)hash_find(&cp->hash_array, key, key_len);
+	pthread_mutex_unlock(&cp->lock);
+	if (cm == NULL)
+	{
+		logError("file: "__FILE__", line: %d, " \
+			"hash entry of server %s:%d not exist", __LINE__, \
+			conn->ip_addr, conn->port);
+		return ENOENT;
+	}
+
+	node = (ConnectionNode *)(((char *)conn) + sizeof(ConnectionInfo));
+	if (node->manager != cm)
+	{
+		logError("file: "__FILE__", line: %d, " \
+			"manager of server entry %s:%d is invalid!", \
+			__LINE__, conn->ip_addr, conn->port);
+		return EINVAL;
+	}
+
+	pthread_mutex_lock(&cm->lock);
+	if (bForce)
+	{
+		cm->total_count--;
+
+		logDebug("file: "__FILE__", line: %d, " \
+			"server %s:%d, release connection: %d, " \
+			"total_count: %d, free_count: %d", 
+			__LINE__, conn->ip_addr, conn->port, 
+			conn->sock, cm->total_count, cm->free_count);
+
+		conn_pool_disconnect_server(conn);
+		free(conn);
+	}
+	else
+	{
+		node->atime = get_current_time();
+		node->next = cm->head;
+		cm->head = node;
+		cm->free_count++;
+
+		logDebug("file: "__FILE__", line: %d, " \
+			"server %s:%d, free connection: %d, " \
+			"total_count: %d, free_count: %d", 
+			__LINE__, conn->ip_addr, conn->port, 
+			conn->sock, cm->total_count, cm->free_count);
+	}
+	pthread_mutex_unlock(&cm->lock);
+
+	return 0;
+}
+
+static int _conn_count_walk(const int index, const HashData *data, void *args)
+{
+	int *count;
+	ConnectionManager *cm;
+	ConnectionNode *node;
+
+	count = (int *)args;
+	cm = (ConnectionManager *)data->value;
+	node = cm->head;
+	while (node != NULL)
+	{
+		(*count)++;
+		node = node->next;
+	}
+
+	return 0;
+}
+
+int conn_pool_get_connection_count(ConnectionPool *cp)
+{
+	int count;
+	count = 0;
+	hash_walk(&cp->hash_array, _conn_count_walk, &count);
+	return count;
+}
+

src/connection_pool.h

+/**
+* Copyright (C) 2008 Happy Fish / YuQing
+*
+* FastDFS may be copied only under the terms of the GNU General
+* Public License V3, which may be found in the FastDFS source kit.
+* Please visit the FastDFS Home Page http://www.csource.org/ for more detail.
+**/
+
+//connection_pool.h
+
+#ifndef _CONNECTION_POOL_H
+#define _CONNECTION_POOL_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "common_define.h"
+#include "pthread_func.h"
+#include "hash.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct
+{
+	int sock;
+	int port;
+	char ip_addr[IP_ADDRESS_SIZE];
+} ConnectionInfo;
+
+struct tagConnectionManager;
+
+typedef struct tagConnectionNode {
+	ConnectionInfo *conn;
+	struct tagConnectionManager *manager;
+	struct tagConnectionNode *next;
+	time_t atime;  //last access time
+} ConnectionNode;
+
+typedef struct tagConnectionManager {
+	ConnectionNode *head;
+	int total_count;  //total connections
+	int free_count;   //free connections
+	pthread_mutex_t lock;
+} ConnectionManager;
+
+typedef struct tagConnectionPool {
+	HashArray hash_array;  //key is ip:port, value is ConnectionManager
+	pthread_mutex_t lock;
+	int connect_timeout;
+	int max_count_per_entry;  //0 means no limit
+
+	/*
+	connections whose the idle time exceeds this time will be closed
+	*/
+	int max_idle_time;
+} ConnectionPool;
+
+int conn_pool_init(ConnectionPool *cp, int connect_timeout, \
+	const int max_count_per_entry, const int max_idle_time);
+void conn_pool_destroy(ConnectionPool *cp);
+
+ConnectionInfo *conn_pool_get_connection(ConnectionPool *cp, 
+	const ConnectionInfo *conn, int *err_no);
+
+#define conn_pool_close_connection(cp, conn) \
+	conn_pool_close_connection_ex(cp, conn, false)
+
+int conn_pool_close_connection_ex(ConnectionPool *cp, ConnectionInfo *conn, 
+	const bool bForce);
+
+void conn_pool_disconnect_server(ConnectionInfo *pConnection);
+
+int conn_pool_connect_server(ConnectionInfo *pConnection, \
+		const int connect_timeout);
+
+int conn_pool_get_connection_count(ConnectionPool *cp);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+