I can read from my local psql instance like this:
engine = create_engine('postgresql://postgres:postgres#localhost/db_name')
df = pd.read_sql("select * from table_name;", engine)
I have a remote postgresql sever which I successfully accessed with ssh tunneling both in PgAdmin4 and pycharm. I use public key file to login into remote server. Now, my question is how do I access that database with pandas. I tried:
engine = create_engine('postgresql://username:password#localhost/db_name')
Here, username and password are of remote database. I get sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) FATAL: password authentication failed for user. However, with the same username and password I can access the table in PgAdmin.
From what I read, because of ssh tunneling I have to use localhost and not the remote server address, right? In pgAdmin I can see that the server is running. So, my question is how do I read the table from remote postgresql database with ssh tunneling? In examples I have seen people using different port (different than 5432) but for me the setup only works if I use port 5432. I have disconnected all other servers to avoid the port conflict but I get the same error.
The tunnel created by pgAdmin4 is intended for its own use. It does not arrange for it to listen on 5432, it picks some arbitrary high numbered port and doesn't advertise what port that is. While you can discover what port it is listening on using system tools (like netstat) and then connect to it, you would probably be better served by finding some other way to set up your tunnel. There are python libraries that can help with that.
As for why you can connect to 5432 at all, clearly there is something listening there which is either PostgreSQL or pretending to be PostgreSQL, but it doesn't seem to be the one you intend. You can use netstat -ao to find the pid for it and then look up based on that.
Related
I wish to connect to a database server through my local machine at work, but I do not have direct access to the database server (due to security reasons). The database server is accessible through another intermediary server which I can connect to.
I understand I can connect to the database if I run my script on the intermediary server, but is there any way through which I can connect to the database server directly through my local machine?
I am trying to do this in a Python script as I wish to read the data into a pandas dataframe (I can do this part once I can set up the connection).
If you have SSH access to that intermediary server you can connect via an SSH tunnel. This post describes how to do that: Enable Python to Connect to MySQL via SSH Tunnelling
I have a mysql database on a server for work. I ssh ont the server and then enter the database using mysql -u username -p at which time the command line will prompt me for my password.
I'd like to access the database remotely for some development. I see that mysql.connector is a library for connecting to mysql databases, but can I ssh onto the server and then access the database using python?
You can use SSH tunneling to redirect a port listening on your local machine to a port on the remote machine.
ssh -L9999:localhost:3306 me#my.work.com
This will redirect traffic from port 9999 on your machine to port 3306 on my.work.com. We gave localhost to -L since we want to tunnel to the server itself. We could also create a tunnel through your work server to some machine accessible to it only.
Now you can connect your connector on your own machine using port 9999 and the traffic is tunneled to my.work.com:3306.
You can use the tunnel.py code from https://gist.github.com/shnjp/856179.
with make_tunnel('me#mywork.com:3306') as t:
mysql.connector.connect(host='localhost',
database='mysql',user='root',password='PASS')
This assumes that your localhost doesn't have any application running on port 3306. If you have some, then you need to use "port=" argument in make_tunnel and provide a different port to use on the localhost.
You can also connect from python to the database without using any tunnel.
For that, enable the mysql server to allow connections from the outside uncommenting and changing the bind-address line in the /etc/mysql/my.cnf file to bind-address = 0.0.0.0. After that, restart the server with sudo service mysql restart and finally grant permissions to your user to access from the outside GRANT SELECT,INSERT,UPDATE,DELETE ON your_database.* TO 'your_user'#'%' IDENTIFIED BY 'your_pass';
Now you'll be able to connect from python to the database
import mysql.connector
ip_of_the_database = 'x.x.x.x'
cnx = mysql.connector.connect(host = ip_of_the_database,
user = 'your_user',
password = 'your_pass',
database = 'your_database')
I'm writing a small python program locally as i don't have root access on the server. It basically does a lot of mysql queries using python MySQLdb module.
The thing is I cant use MySQLdb with the server, as the mysql server is hosted locally and I need to ssh into the server and then use mysql from there.
Is there any module available where I can connect to a mysql database via SSH.
At the moment I can connect to the mysql instance using SSH credentials (IP, User, Pass)
I also have the user/pass for the mysql instance and I'm pretty sure it runs on 127.0.0.1/localhost.
If you're set on Python, I would use paramiko:
https://github.com/paramiko/paramiko
This seems to be one of the most widely used Python SSH libraries. There are some other StackOverflow questions that address how to do this.
How to open an SSH tunnel using python?
SSH Tunnel for Python MySQLdb connection
The main idea is to create a tunnel with paramiko and then connect to the localhost port through which you are tunneling traffic to the remote server using the Python library MySQLdb.
I am not a network/web/internet programmer so please excuse my noobness in this area. I have gotten a website using a free hosting service. They include one MySQL database. Here are the details for the database:
port = 3306
host = "fdb4.biz.nf"
database = "1284899_6067"
user = "1284899_6067"
password = "somepass9351"
I am using MySQLdb module (installed on my CLIENT machine - not server) to connect to this database:
db = MySQLdb.connect(host=host, user=user, passwd=password, db=database,port=port)
But I get the following error:
OperationalError: (2003, "Can't connect to MySQL server on 'fdb4.biz.nf' (10060)
What I have already tried
tried two different databases from different hosts
tried changing the port
tried searching SO for similar answers but all others connect to 'local host'
What I think:
could this be caused by my firewall? I am using my school's internet. I don't think this could be it because I am on CLIENT so if anything it is the SERVER'S firewall.
Two questions
Can MySQLdb be used to connect to a db on a SERVER when it is imported on a CLIENT?
If yes, what am I doing wrong?
Thank you so much for any help, its greatly appreciated! Been stuck the whole day on this.
For security reasons, mysql only listens for connections from localhost. Error code 10060 is basically that: you are not allowed to connect remotely.
Solution: find a my.ini (or my.cnf in linux) and try to find a line:
bind-address = 127.0.0.1
this line says: allow only local connections. So, you should comment-out this line, or set your IP address.
Yes, MySQLdb can connect to remote hosts.
And your usage of the connect method is correct.
You should first check if you can connect to the remote mysql server from your mysql client.
In terminal you can type mysql -h hostname -u username -p databasename
This should prompt you for the password. Enter the password. Can you connect?
If you can't connect, then you have an access problem, and its not a python - mysqldb problem
Either the server is not reachable because it is behind a firewall, in that case your client machine's ip needs to be whitelisted. Check your firewall settings
Or, the mysql server running on the remote machine is configured to accept only local connections. I think this is the default, but I'm not sure. You should ssh into the server remote host where the database server is running, locate the my.cnf file on the server and check the settings. Depending on your mysql version, the configuration would look slightly different.
Or, the user that you're trying to connect as is not associated with the ip that you're trying to connect from. Mysql users have two parts, like this: 'username'#'host'. To enable a user to connect from all ips the user needs to look like this 'user'#'%'.
I hope I've given you enough to try to debug this issue.
Things to note in advance:
I am using wampserver 2.2
Ive forwarded port 80
I added a rule to my firewall to accept traffic through port 3306
I have added "Allow from all" in directory of "A file i forget"
My friend can access my phpmyadmin server through his browser
I am quite the novice, so bear with me.
I am trying to get my friend to be able to alter my databases on my phpmyadmin server through
python. I am able to do so on the host machine using "127.0.0.1" as the HOST. My Question is, does he have to use my external ip as the HOST or my external ip/phpmyadmin/ as the HOST? And if using the external ip iscorrect...What could the problem be?
If your phpmyadmin runs on the same machine as mysql-server, 127.0.0.1 is enough (and safer if your mysql server binds to 127.0.0.1, rather than 0.0.0.0) if you use tcp(rather than unix socket).