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Python如何管理多个PostgreSQL数据库的连接

作者：jzy3711

这篇文章主要为大家详细介绍了Python如何通过读取配置文件中的PostgreSQL服务信息,连接到相应的PostgreSQL数据库,感兴趣的小伙伴可以了解下

主要实现了通过读取配置文件中的PostgreSQL服务信息，连接到相应的PostgreSQL数据库。提供了两个连接函数，postgresql_connect 和 postgresql_connect_encode，分别是普通的和带编码参数的连接函数。

操作步骤

1.导入相关库

from pyhive import hive
import cx_Oracle
import pymysql
import pymssql
from optparse import OptionParser
import logging
import sys
import traceback
import re
import warnings
with warnings.catch_warnings(record=True):
    import psycopg2
reload(sys)

2. 配置PostgreSQL连接信息

这里定义了一个包含多个PostgreSQL服务配置信息的列表pgconfigs。每个配置项由数据库名称、用户、密码、主机和端口组成。

pgconfigs = [
    {"asset_factory": {"database": "asset_factory", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"asset_register": {"database": "asset_register", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"creditdb": {"database": "creditdb", "user": "credit", "password": "hHJ98#pE40Y", "host": "10.251.101.175", "port": "18923"}},
    {"asset_portal": {"database": "asset_portal", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"tyjh": {"database": "tyjh", "user": "tyjh", "password": "k5y2dwoKcFm&^OsW", "host": "10.251.90.35", "port": "18922"}},
    {"cwrl": {"database": "cwrl", "user": "cwjh_yaxin", "password": "eKYy4R3&MbaaY3Zy", "host": "10.251.90.34", "port": "18921"}},
    {"dc_new_pg": {"database": "dc", "user": "dc", "password": "Ojjkcy@jVxKIeo5C", "host": "10.251.90.36", "port": "18923"}},
    {"credit_data": {"database": "credit_data", "user": "credit_data", "password": "@G*1f*3$3DzTH6%o", "host": "10.251.90.134", "port": "18923"}},
    {"new_jf_pg_cd": {"database": "accthuiju", "user": "datacenter", "password": "KridU593&%rj90", "host": "133.37.116.192", "port": "18921"}},
    {"new_accthuiju": {"database": "accthuiju", "user": "itf_ods", "password": "2dH~fZ^8", "host": "10.251.64.226", "port": "18921"}},
    {"crm3huijupg": {"database": "crm3huijupg", "user": "datacenter", "password": "lp*36^YD", "host": "10.251.65.93", "port": "18921"}},
    {"crm3hispg": {"database": "crm3hispg", "user": "datacenter", "password": "~4nD_jWG", "host": "10.251.64.196", "port": "18921"}},
    {"hana": {"database": "hana", "user": "hana", "password": "gvptHKXVNKEGw7pk", "host": "10.251.90.94", "port": "18924"}},
    {"dataos_71_pg_dev": {"database": "dacp", "user": "dacp", "password": "jxFgCKv9GJw2ohS3", "host": "10.251.110.104", "port": "18921"}}
]

3. 定义连接函数

普通连接函数

def postgresql_connect(servicename):
    global job_task_content_ori
    global job_resource_conn_info
    global job_hdfs_dir_info
    try:
        for subconfig in pgconfigs:
            if servicename in subconfig:
                pgconfig = subconfig[servicename]
                conn = psycopg2.connect(database=pgconfig["database"], user=pgconfig["user"],
                                        password=pgconfig["password"], host=pgconfig["host"], port=pgconfig["port"])
                return conn
        print("servicename %s not found in config dictionary" % servicename)
        sys.exit(6)
    except:
        traceback.print_exc()
        print("connect pg error " + pgconfig["database"])
        sys.exit(6)

上述代码中的postgresql_connect函数：

带编码参数的连接函数

def postgresql_connect_encode(servicename, encoding='UTF-8'):
    global job_task_content_ori
    global job_resource_conn_info
    global job_hdfs_dir_info
    try:
        for subconfig in pgconfigs:
            if servicename in subconfig:
                pgconfig = subconfig[servicename]
                conn = psycopg2.connect(database=pgconfig["database"], user=pgconfig["user"],
                                        password=pgconfig["password"], host=pgconfig["host"], port=pgconfig["port"],
                                        client_encoding=encoding)
                return conn
        print("servicename %s not found in config dictionary" % servicename)
        sys.exit(6)
    except:
        traceback.print_exc()
        print("connect pg error " + pgconfig["database"])
        sys.exit(6)

postgresql_connect_encode函数与前一个函数类似，唯一的区别是它接受一个可选的编码参数encoding，并将其传递给psycopg2.connect以设定客户端编码。

4.解释关键点

配置管理：pgconfigs列表包含多个数据库配置，便于根据服务名快速查找匹配的配置项。

错误处理：在连接失败时，打印堆栈跟踪以帮助调试并退出程序。

编码管理：对于需要特定编码的连接，提供了额外的函数来设置编码。

5.使用示例

假设你要连接到名为 dataos_71_pg_dev 的PostgreSQL服务，可以像下面这样使用这些函数：

# 普通连接
conn = postgresql_connect("dataos_71_pg_dev")

# 带编码参数的连接
conn_with_encoding = postgresql_connect_encode("dataos_71_pg_dev", encoding='UTF-8')

完整python

#!/data/apps/python2715/bin/python
# -*- coding:utf-8 -*-

from pyhive import hive
import cx_Oracle
import pymysql
import pymssql
from optparse import OptionParser
import logging
import sys
import traceback
import re
import warnings
with warnings.catch_warnings(record=True):
    import psycopg2
reload(sys)

pgconfigs = [
    {"asset_factory": {"database": "asset_factory", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"asset_register": {"database": "asset_register", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"creditdb": {"database": "creditdb", "user": "credit", "password": "hHJ98#pE40Y", "host": "10.251.101.175", "port": "18923"}},
    {"asset_portal": {"database": "asset_portal", "user": "asset", "password": "Ro20ot16", "host": "10.251.80.202", "port": "65432"}},
    {"tyjh": {"database": "tyjh", "user": "tyjh", "password": "k5y2dwoKcFm&^OsW", "host": "10.251.90.35", "port": "18922"}},
    {"cwrl": {"database": "cwrl", "user": "cwjh_yaxin", "password": "eKYy4R3&MbaaY3Zy", "host": "10.251.90.34", "port": "18921"}},
    {"dc_new_pg": {"database": "dc", "user": "dc", "password": "Ojjkcy@jVxKIeo5C", "host": "10.251.90.36", "port": "18923"}},
    {"credit_data": {"database": "credit_data", "user": "credit_data", "password": "@G*1f*3$3DzTH6%o", "host": "10.251.90.134", "port": "18923"}},
    {"new_jf_pg_cd": {"database": "accthuiju", "user": "datacenter", "password": "KridU593&%rj90", "host": "133.37.116.192", "port": "18921"}},
    {"new_accthuiju": {"database": "accthuiju", "user": "itf_ods", "password": "2dH~fZ^8", "host": "10.251.64.226", "port": "18921"}},
    {"crm3huijupg": {"database": "crm3huijupg", "user": "datacenter", "password": "lp*36^YD", "host": "10.251.65.93", "port": "18921"}},
    {"crm3hispg": {"database": "crm3hispg", "user": "datacenter", "password": "~4nD_jWG", "host": "10.251.64.196", "port": "18921"}},
    {"hana": {"database": "hana", "user": "hana", "password": "gvptHKXVNKEGw7pk", "host": "10.251.90.94", "port": "18924"}},
    {"dataos_71_pg_dev": {"database": "dacp", "user": "dacp", "password": "jxFgCKv9GJw2ohS3", "host": "10.251.110.104", "port": "18921"}}
]


def postgresql_connect(servicename):
    global job_task_content_ori
    global job_resource_conn_info
    global job_hdfs_dir_info
    try:
        for subconfig in pgconfigs:
           if subconfig.has_key(servicename):
                pgconfig = subconfig[servicename]
                conn = psycopg2.connect(database=pgconfig["database"], user=pgconfig["user"],
                                        password=pgconfig["password"], host=pgconfig["host"], port=pgconfig["port"])
                return conn
        print("servinamename %s not found in config dictionary" % servicename)
        sys.exit(6)
    except:
        traceback.print_exc()
        print("connect pg error " + pgconfig["database"])
        sys.exit(6)


def postgresql_connect_encode(servicename, encoding='UTF-8'):
    global job_task_content_ori
    global job_resource_conn_info
    global job_hdfs_dir_info
    try:
        for subconfig in pgconfigs:
            if subconfig.has_key(servicename):
                pgconfig = subconfig[servicename]
                conn = psycopg2.connect(database=pgconfig["database"], user=pgconfig["user"],
                                        password=pgconfig["password"], host=pgconfig["host"], port=pgconfig["port"],
                                        client_encoding=encoding)
                return conn
        print("servinamename %s not found in config dictionary" % servicename)
        sys.exit(6)
    except:
        traceback.print_exc()
        print("connect pg error " + pgconfig["database"])
        sys.exit(6)

总结

这段代码展示了如何通过配置文件管理多个PostgreSQL数据库的连接，提供了普通连接和带编码参数的连接函数，确保了代码的灵活性和可重用性。通过处理异常和提供详细的错误信息，也提高了代码的可靠性和可维护性。

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