问题:在Python脚本中使用PSQL pg_dump
和pg_restore
并使用subprocess
模块。
后台:我正在使用localhost中的以下python 2.7
脚本(即Ubuntu 14.04.5 LTS
)来创建PSQL服务器中表的备份(即{{1在较新版本的PSQL服务器(即PostgreSQL 9.4.11
)中将其恢复到远程主机(即Ubuntu 16.04.2 LTS
)。
PostgreSQL 9.6.2
当我按上述顺序使用函数时,#!/usr/bin/python
from subprocess import PIPE,Popen
def dump_table(host_name,database_name,user_name,database_password,table_name):
command = 'pg_dump -h {0} -d {1} -U {2} -p 5432 -t public.{3} -Fc -f /tmp/table.dmp'\
.format(host_name,database_name,user_name,table_name)
p = Popen(command,shell=True,stdin=PIPE)
return p.communicate('{}\n'.format(database_password))
def restore_table(host_name,database_name,user_name,database_password):
command = 'pg_restore -h {0} -d {1} -U {2} < /tmp/table.dmp'\
.format(host_name,database_name,user_name)
p = Popen(command,shell=True,stdin=PIPE)
return p.communicate('{}\n'.format(database_password))
def main():
dump_table('localhost','testdb','user_name','passwd','test_tbl')
restore_table('remotehost','new_db','user_name','passwd')
if __name__ == "__main__":
main()
函数成功完成并创建dump_table()
文件,但/tmp/table.sql
函数返回以下错误:
('','密码:\ npg_restore:[archiver(db)]与数据库的连接 “database_name”失败:致命:用户密码验证失败 “username”\ nFATAL:用户密码验证失败 “用户名” \ N')*
我已查看过凭据&amp;通过在shell中执行restore_table()
的命令输出,我还包括.pgpass的凭据(虽然因为我在pg_restore
传递密码而不相关)
有没有类似的经历?我几乎被困住了!
此致 d。
答案 0 :(得分:2)
以下作品和所做的更改已被评论。
我不确定为什么pg_restore
在使用完整命令(即未在列表中拆分)并在shell=True
中使用Popen
时产生密码验证错误,但pg_dump
另一方面,1}}使用shell=True
&amp;完整的命令。 <
是否必须对此做任何事情?
#!/usr/bin/python
from subprocess import PIPE,Popen
import shlex
def dump_table(host_name,database_name,user_name,database_password,table_name):
command = 'pg_dump -h {0} -d {1} -U {2} -p 5432 -t public.{3} -Fc -f /tmp/table.dmp'\
.format(host_name,database_name,user_name,table_name)
p = Popen(command,shell=True,stdin=PIPE,stdout=PIPE,stderr=PIPE)
return p.communicate('{}\n'.format(database_password))
def restore_table(host_name,database_name,user_name,database_password):
#Remove the '<' from the pg_restore command.
command = 'pg_restore -h {0} -d {1} -U {2} /tmp/table.dmp'\
.format(host_name,database_name,user_name)
#Use shlex to use a list of parameters in Popen instead of using the
#command as is.
command = shlex.split(command)
#Let the shell out of this (i.e. shell=False)
p = Popen(command,shell=False,stdin=PIPE,stdout=PIPE,stderr=PIPE)
return p.communicate('{}\n'.format(database_password))
def main():
dump_table('localhost','testdb','user_name','passwd','test_tbl')
restore_table('localhost','testdb','user_name','passwd')
if __name__ == "__main__":
main()
答案 1 :(得分:0)
您可以对pg_dump使用环境变量https://www.postgresql.org/docs/11/libpq-envars.html和“ --no-password”选项。
def dump_schema(host, dbname, user, password, **kwargs):
command = f'pg_dump --host={host} ' \
f'--dbname={dbname} ' \
f'--username={user} ' \
f'--no-password ' \
f'--format=c ' \
f'--file=/tmp/schema.dmp '
proc = Popen(command, shell=True, env={
'PGPASSWORD': password
})
proc.wait()
答案 2 :(得分:0)
这是一个用于获取postgres转储并将其还原到新数据库的python脚本。
import subprocess
DB_NAME = 'PrimaryDB' # your db name
DB_USER = 'postgres' # you db user
DB_HOST = "localhost"
DB_PASSWORD = 'sarath1996'# your db password
dump_success = 1
print ('Backing up %s database ' % (DB_NAME))
command_for_dumping = f'pg_dump --host={DB_HOST} ' \
f'--dbname={DB_NAME} ' \
f'--username={DB_USER} ' \
f'--no-password ' \
f'--file=backup.dmp '
try:
proc = subprocess.Popen(command, shell=True, env={
'PGPASSWORD': DB_PASSWORD
})
proc.wait()
except Exception as e:
dump_success = 0
print('Exception happened during dump %s' %(e))
if dump_success:
print('db dump successfull')
print(' restoring to a new database database')
"""database to restore dump must be created with
the same user as of previous db (in my case user is 'postgres').
i have #created a db called ReplicaDB. no need of tables inside.
restore process will #create tables with data.
"""
backup_file = '/home/Downloads/BlogTemplate/BlogTemplate/backup.dmp'
"""give absolute path of your dump file. This script will create the backup.dmp in the same directory from which u are running the script """
if not dump_success:
print('dump unsucessfull. retsore not possible')
else:
try:
process = subprocess.Popen(
['pg_restore',
'--no-owner',
'--dbname=postgresql://{}:{}@{}:{}/{}'.format('postgres',#db user
'sarath1996', #db password
'localhost', #db host
'5432', 'ReplicaDB'), #db port ,#db name
'-v',
backup_file],
stdout=subprocess.PIPE
)
output = process.communicate()[0]
except Exception as e:
print('Exception during restore %e' %(e) )