Develop Reference

how to fix cx_Oracle.DatabaseError: ORA-12170: TNS:Connect timeout occurred

I am trying to run a Python script to insert some data into an Oracle table, from a docker image.
I was given following connection string :
jdbc:oracle:thin:#(DESCRIPTION=(CONNECT_TIMEOUT=3)(RETRY_COUNT=2)(FAILOVER=ON)(LOAD_BALANCE=NO) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_1)(PORT=1521))) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_2)(PORT=1521))) (CONNECT_DATA=(SERVICE_NAME=service_name))) 
I'm trying to connect using cx_Oracle package :
try:
# establish a new connection
with cx_Oracle.connect(self.oracle_user,
self.oracle_pwd,
self.oracle_dsn) as connection:
logger.info('ElasticsearchFinder.oracle_write : connexion established with DB')
with oracle_dsn being the connexion string (minus the jdbc:oracle:thin:# part)
I also tried things like
cx_Oracle.connect(self.oracle_user+'/'+self.oracle_pwd+'#'+self.oracle_dsn)
as seen in some examples, but I always get the following timeout error :
cx_Oracle.DatabaseError: ORA-12170: TNS:Connect timeout occurred
telnet host 1521 works fine, I also tried changing the CONNECT_TIMEOUT value.
I also tried
dsn_tns = cx_Oracle.makedsn(self.oracle_host, self.oracle_port, service_name = self.oracle_service_name)
cx_Oracle.connect(self.oracle_user,self.oracle_pwd,dsn_tns)
as suggested here but then I get
cx_Oracle.DatabaseError: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
I am running my script from a Docker image build with Dockerfile :
FROM oraclelinux:7.8
RUN yum -y install oracle-release-el7 && \
yum-config-manager --enable ol7_oracle_instantclient && \
yum -y install oracle-instantclient18.3-basic && \
rm -rf /var/cache/yum
COPY ./fetch_session_iptv.py /opt/
COPY ./conf/fetch_session_iptv.conf /opt/conf/
#COPY ./conf/certs/* /opt/conf/certs/
COPY ./logs /opt/logs
RUN yum install -y \
#https://yum.oracle.com/repo/OracleLinux/OL7/developer/x86_64/getPackage/oracle-instantclient18.3-basic-18.3.0.0.0-2.x86_64.rpm \
https://yum.oracle.com/repo/OracleLinux/OL7/developer/x86_64/getPackage/python-cx_Oracle-7.3-1.el7.x86_64.rpm \
https://yum.oracle.com/repo/OracleLinux/OL7/developer/x86_64/getPackage/python36-pytz-2016.10-2.0.1.el7.noarch.rpm
COPY ./python_requirements/elasticsearch-7.8.0-py2.py3-none-any.whl .
COPY ./python_requirements/certifi-2020.4.5.2-py2.py3-none-any.whl .
COPY ./python_requirements/urllib3-1.25.9-py2.py3-none-any.whl .
RUN pip3 install --user \
certifi-2020.4.5.2-py2.py3-none-any.whl \
urllib3-1.25.9-py2.py3-none-any.whl \
elasticsearch-7.8.0-py2.py3-none-any.whl \
cx_Oracle
RUN sh -c "echo /usr/lib/oracle/18.3/client64/lib > /etc/ld.so.conf.d/oracle-instantclient.conf"
RUN ldconfig
RUN export ORACLE_HOME=/usr/lib/oracle/18.3/client64/
RUN yum -y install telnet
#CMD ["/bin/bash"]
CMD [ "python3", "/opt/fetch_session_iptv.py" ]
I can't understand what's going wrong?
[UPDATE] I've set
ORACLE_HOME=/usr/lib/oracle/18.3/client64/bin
TNS_ADMIN=$ORACLE_HOME/admin
LD_LIBRARY_PATH=/usr/lib/oracle/18.3/client64/lib
PATH=$PATH:$ORACLE_HOME
I've added a tnsnames.ora file in TNS_ADMIN directory, with
CNX=(DESCRIPTION=(CONNECT_TIMEOUT=3)(RETRY_COUNT=2)(FAILOVER=ON)(LOAD_BALANCE=NO) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_1)(PORT=1521))) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_2)(PORT=1521))) (CONNECT_DATA=(SERVICE_NAME=service_name)))
Now, when I try sqlplus MY_USER#CNX I get the same :
ORA-12170: TNS:Connect timeout occured
but at least it seems to accept the connexion string and user. Prior to setting all the environment variables correctly, I only got different TNS error messages about TNS: listener does not currently know of service requested in connect descriptor or the net service name being incorrect.
[UPDATE 2]
I've checked with the person who gave me all connexion info: user, password and connection string are correct. They're running Oracle Database 12c (12.1.0.2.0), which according to this page is compatible with the 18c client I'm using.
I don't know what else could be a possible reason for this timeout error?

Start by using the equivalent connection string in cx_Oracle:
self.oracle_dsn = "(DESCRIPTION=(CONNECT_TIMEOUT=3)(RETRY_COUNT=2)(FAILOVER=ON)(LOAD_BALANCE=NO) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_1)(PORT=1521))) (ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host_2)(PORT=1521))) (CONNECT_DATA=(SERVICE_NAME=service_name)))"
try:
# establish a new connection
with cx_Oracle.connect(self.oracle_user,
self.oracle_pwd,
self.oracle_dsn) as connection:
logger.info('ElasticsearchFinder.oracle_write : connexion established with DB')
The cx_Oracle manual on connecting and connect strings is here.
Personally I'd use 19c Instant Client, which will connect to the same DB versions as 18c - and doesn't need to have ldconfig run. See Docker for Oracle Database Applications in Node.js and Python.
Update your question with information and I can update this answer likewise.

How to connect to Azure MySQL from Azure Functions by Python

I am trying to;
Run the python code triggered by Cosmos DB when cosmos DB receives the data..
The python code in Azure Functions has code to ingest data from Azure MySQL.
What I have done are;
. Wrote python in Azure Functions and run it with triggered by Cosmos
DB. This was successful.
. Installed mysql.connector referred to
https://prmadi.com/running-python-code-on-azure-functions-app/ and
run the code to connect to Azure MySQL, but It does not work.
Do you know how to install mysql module for Python to Azure Functions and connect to the database?
Thanks!

According to your description ,I think your issue is about how to install the Python third-party module in the Azure function app.
Please refer to the steps as below :
Step 1 :
login kudu : https://Your_APP_NAME.scm.azurewebsites.net/DebugConsole.
Run Below command in d:/home/site/wwwroot/<your function name> folder.(will take some time)
python -m virtualenv myvenv
Step 2 :
Load the env via the below command in env/Scripts folder.
activate.bat
Step 3 :
Your shell should be now prefixed by (env).
Update pip
python -m pip install -U pip
Install what you need
python -m pip install MySQLdb
Step 4 :
In your code, update the sys.path to add this venv:
import sys, os.path
sys.path.append(os.path.abspath(os.path.join(os.path.dirname( __file__ ), 'env/Lib/site-packages')))
Then connect to mysql db via the snippet of code below
#!/usr/bin/python
import MySQLdb
# Connect
db = MySQLdb.connect(host="localhost",
user="appuser",
passwd="",
db="onco")
cursor = db.cursor()
# Execute SQL select statement
cursor.execute("SELECT * FROM location")
# Commit your changes if writing
# In this case, we are only reading data
# db.commit()
# Get the number of rows in the resultset
numrows = cursor.rowcount
# Get and display one row at a time
for x in range(0, numrows):
row = cursor.fetchone()
print row[0], "-->", row[1]
# Close the connection
db.close()
Hope it helps you.

Python module PyMySQL not taking arguments

I wrote a python script that communicate with MySQL server on OSX 10.10, it runs fine Mac until I put it on an VPS running Ubuntu 14.04
The problem mainly lies on the pyMySQL module. :I can't even run their example script on the git page here
for running the following code:
import pymysql.cursors
# Connect to the database
connection = pymysql.connect(host='localhost',
user='user',
password='passwd',
db='db',
charset='utf8mb4',
cursorclass=pymysql.cursors.DictCursor)
try:
with connection.cursor() as cursor:
# Create a new record
sql = "INSERT INTO `users` (`email`, `password`) VALUES (%s, %s)"
cursor.execute(sql, ('webmaster#python.org', 'very-secret'))
# connection is not autocommit by default. So you must commit to save
# your changes.
connection.commit()
with connection.cursor() as cursor:
# Read a single record
sql = "SELECT `id`, `password` FROM `users` WHERE `email`=%s"
cursor.execute(sql, ('webmaster#python.org',))
result = cursor.fetchone()
print(result)
finally:
connection.close()
The result is
Traceback (most recent call last):
File "1.py", line 9, in <module>
cursorclass=pymysql.cursors.DictCursor)
File "build/bdist.linux-x86_64/egg/pymysql/__init__.py", line 93, in Connect
TypeError: __init__() got an unexpected keyword argument 'password'
Environment:
Ubuntu 14.04 x86_64
Python 2.7.10
PyMySQL 0.6.7
Mac is running the above script fine but not the ubuntu.
Thanks in advance.

I didn't do much checking on the error message. Instead I uninstall all the packages on the unbuntu server and follow the package list on the Mac to install them again one by one to the same version. Amazingly, the problem is solved. Unfortunately I can't tell which module is causing the problem
You might want to give it a try if you don't want to spend much time on updating modules one by one.

It seems that this is a ubuntu problem, which is solved if you install the latest pypi version.
I removed the package from ubuntu in dist-packages and installed it in site-packages:
sudo apt-get purge python3-pymysql
sudo pip3 install --upgrade pymysql
You don't (really) want to do this, especially on a server. Alternatively you use a virtualenv:
virtualenv -p python3.4 venv3
source venv3/bin/activate
pip3 install --update pip
pip3 install --update pymysql
You need to learn a bit more about virtualenv's to use them, but the idea is that you have a complete and separate python3.4 environment installed in venv3 which you activate with source venv3/bin/activate. This way it is harder to break your ubuntu (which heavily depends on a working python). Moreover, you can install different versions of packages in different virtualenv's. Also, when debugging, you can add print-statements to python-code in the site-packages folder of the virtualenv, without risking breaking your system severely. This is great, as many good python libraries have poor error reporting.

Faced this error with Python:3.6, PyMySQL3:0.5.
solution: change 'password' parameter to 'passwd'
Below is the parameters list with default values
host="localhost", user=None, passwd="", db=None, port=3306, unix_socket=None, charset='', sql_mode=None, read_default_file=None, conv=decoders, use_unicode=None, client_flag=0, cursorclass=Cursor, init_command=None, connect_timeout=None, ssl=None, read_default_group=None, compress=None, named_pipe=None

Create a DSN for pyodbc similar to PHP PDO. Is it possible?

I use PHP PDO to connect a MySql Db and it works great. I have something like:
$dsn = 'mysql:host=localhost;dbname=database_name';
$user_db = 'admin';
$password = 'password';
$pdo = new PDO($dsn, $user_db, $password);
Now I need to load same database from a python script and I have to use pypodbc module
But I'm getting some issue:
If I do (on Python):
pyodbc.connect('DRIVER={MySQL};SERVER=localhost;DATABASE=database_name;UID=admin;PWD=password;')
I got en error on log:
pyodbc.Error: ('01000', "[01000] [unixODBC][Driver Manager]Can't open
lib '/usr/lib64/libmyodbc5.so' : file not found (0)
(SQLDriverConnect)")
If i check the /etc/odbcinst.ini i can see:
# Driver from the mysql-connector-odbc package
# Setup from the unixODBC package
[MySQL]
Description = ODBC for MySQL
Driver = /usr/lib/libmyodbc5.so
Setup = /usr/lib/libodbcmyS.so
Driver64 = /usr/lib64/libmyodbc5.so
Setup64 = /usr/lib64/libodbcmyS.so
FileUsage = 1
I tried to add the the package mysql-connector-odbc by YUM and i got mysql-connector-odbc.x86_64 0:5.1.5r1144-7.el6
And then running my script I got a new error:
/usr/local/bin/python2.7: relocation error: /usr/lib64/libmyodbc5.so: symbol strmov, version libmysqlclient_16 not defined in file libmysqlclient_r.so.16 with link time reference
It seems this version is not compatible with MySql which I have: 5.5.37-cll - MySQL Community Server (GPL)
I did a YUM REMOVE to restore previous conf.
And now ? Any suggestions ? Thanks!
My configuration:
My Server: CENTOS 6.6 x86_64 virtuozzo
MySql: 5.5.37-cll - MySQL Community Server (GPL)

Finally I fixed it!
yum install unixODBC-devel
yum install mysql-connector-odbc
yum install openssl098e
and than:
rpm -ivh libmysqlclient16-5.1.69-1.w5.x86_64.rpm
Now the
pyodbc.connect('DRIVER={MySQL};SERVER=localhost;DATABASE=database_name;UID=admin;PWD=password;')
works!! yeah!

Problems connecting with Teradata database using pyodbc

Currently, I'm running a simple python script to connect to a database:
import pyodbc
cnxn = pyodbc.connect('DRIVER={Teradata};DBCNAME=(MYDB);UID=(MYUSER); PWD=(MYPASS);QUIETMODE=YES')
With the server and credentials substituted in obviously. However, when running this script, I get the following error:
pyodbc.Error: ('200', '[200] [unixODBC][eaaa[DCTrdt rvr o nuhifraint o n (0) (SQLDriverConnectW)')
The only help I've been able to find is here installed the Teradata ODBC drivers, but I just don't understand why I can't connect. Anyone have any ideas on this?

You have to use like following to connect:
TDCONN = pyodbc.connect('DSN=yourDSNname;',ansi=True, autocommit=True)
You can replace DSN=yourDSNname; with what you have already.

I hit this "non english" error message problem. I think it was due to the wrong versions of libodbc.so and libodbcinst.so being used. Changing the links in /usr/lib/... to point to the teradata installed versions worked for me. Commands using the default install directories in Ubuntu 12.04, 64bit were:
cd /usr/lib/x86_64-linux-gnu
ls -lha | grep odbc (To should see the files below which are to be replaced).
sudo mv libodbc.so.1.0.0 Xlibodbc.so.1.0.0
sudo ln -s /opt/teradata/client/14.10/odbc_64/lib/libodbc.so libodbc.so.1.0.0
sudo mv libodbcinst.so.1.0.0 Xlibodbcinst.so.1.0.0
sudo ln -s /opt/teradata/client/14.10/odbc_64/lib/libodbcinst.so libodbcinst.so.1.0.0
I had also previously installed (through apt-get) odbcinst, so I redirected both files. But possibly only the first is needed.