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Is there an elegant way to deal with an oracle connection by python in pytest?

I am in a project which needs to get datum from an oracle database.
The source code reaches the database by cx_Oracle.
Now I wanna find a way to make a fixture for the connection.
Is there an elegant way to make such a fixture?
Or could somebody recommend a pytest-plugin for Oracle connection?
Thanks in advance.

You can use SQLAlchemy for this. Just plug in your connection string into the create_engine string and create a fixture for the connection (and session) like this:
engine = create_engine('your connection string goes here with your login creds')
#pytest.fixture(scope='module')
def connection():
connection = engine.connect()
yield connection
connection.close()
You can read more about the cx_Oracle connection engine from the SQLAlchemy docs here:
Location
Your create_engine might look something like this:
engine = create_engine("oracle+cx_oracle://<username>:<password>#(DESCRIPTION = (LOAD_BALANCE=on) (FAILOVER=ON) (ADDRESS = (PROTOCOL = TCP)(HOST = <host>)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = devdb)))")
Which was pulled from this post

Using SSL with SQLAlchemy

I've recently changed my project to use SQLAlchemy and my project runs fine, it used an external MySQL server.
Now I'm trying to work with a different MySQL server with SSL CA, and it doesn't connect.
(It did connect using MySQL Workbench, so the certificate should be fine)
I'm using the following code:
ssl_args = {'ssl': {'ca': ca_path}}
engine = create_engine("mysql+pymysql://<user>:<pass>#<addr>/<schema>",
connect_args=ssl_args)
and I get the following error:
Can't connect to MySQL server on '\addr\' ([WinError 10054] An existing connection was forcibly closed by the remote host)
Any suggestions?

I changed the DBAPI to MySQL-Connector, and used the following code:
ssl_args = {'ssl_ca': ca_path}
engine = create_engine("mysql+mysqlconnector://<user>:<pass>#<addr>/<schema>",
connect_args=ssl_args)
And now it works.

If you just connect from a client machine with an ssl connection (so you don't have access to the cert and key), you could simple add ssl=true to your uri.
Edit:
For example:
mysql_db = "mysql+mysqlconnector://<user>:<pass>#<addr>/<schema>?ssl=true"

The official doc is well documented:
engine = create_engine(
db_url,
connect_args={
"ssl": {
"ssl_ca": "ca.pem",
"ssl_cert": "client-cert.pem",
"ssl_key": "client-key.pem"
}
}
)

Another solution is to use sqlalchemy.engine.url.URL to define the URL and pass it to create_engine.
sqlUrl = sqlalchemy.engine.url.URL(
drivername="mysql+pymysql",
username=db_user,
password=db_pass,
host=db_host,
port=3306,
database=db_name,
query={"ssl_ca": "main_app/certs/BaltimoreCyberTrustRoot.crt.pem"},
)
create_engine(sqlUrl)
You can include SSL parameters as a dictionary in the query argument.
This approach is useful if you are using Flask to initialize the SqlAlchemy engine with a config parameter like SQLALCHEMY_DATABASE_URI rather than directly using create_engine.

cx_Oracle.DatabaseError: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

I am trying to do a sanity testing of newly installed Oracle client 12.2 in RHEL 7 linux from a Python program, but it fails with the above error, not sure what I am missing on there. Please help with this case :
cx_Oracle.DatabaseError: ORA-12514: TNS:listener does not currently know of service
requested in connect descriptor
my tnsnames.ora file under /home directory
FRDLD2D1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(Host = frdld2d1.de.db.com)(Port = 1825))
)
(CONNECT_DATA =
(SID = FRDLD2D1)
)
)
and my python program goes below
#!/usr/bin/python
import cx_Oracle
#connection = cx_Oracle.connect('PNTH_LOGGINGB_OWNER/password')
connection = cx_Oracle.connect('PNTH_LOGGINGB_OWNER/password#10.245.63.34:1825/orcl')
cursor = connection.cursor()
querystring = "select * from BDR_JOB_MASTER_LOG where ROWNUM <= 1;"
cursor.execute(querystring)
frdld2d1.de.db.com - IP address : 10.245.63.34
Appreciate if any points the glitch on here.
tnsping utility is not there to test since it is an instaclient version
oracle-instantclient12.2-basic-12.2.0.1.0-1.x86_64.rpm.
But with SQLPlus, I am able to connect the database without any issues.

Please use this as your connection string :
connection = cx_Oracle.connect('PNTH_LOGGINGB_OWNER', 'hdgf_76trf',
cx_Oracle.makedsn('10.245.63.34',1825,'FRDLD2D1') );
Changing SID = FRDLD2D1 to SERVICE_NAME = FRDLD2D1 in your TNSNAMES.ORA file may be an alternative.

You just make dsn in python without config file (tnsnames.ora)
dsn = cx_Oracle.makedsn(host='10.245.63.34', port=1825, sid='FRDLD2D1')
con = cx_Oracle.connect(user='PNTH_LOGGINGB_OWNER', password='password', dsn=dsn)

Python - sqlalchemy - oracle connection fails to connect to SID

I am trying to use sqlalchemy to connect to an oracle DB. I was expecting the following to work given that it appears the exact syntax is shown in the sqlalchemy documentation.
oracle_db = sqlalchemy.create_engine('oracle://user:pass#server:1521/dev')
but this results in the error:
dsn = self.dbapi.makedsn(url.host, port, **makedsn_kwargs)
TypeError: makedsn() takes no keyword arguments
The following call initially works without the service name
oracle_db = sqlalchemy.create_engine('oracle://user:pass#server:1521')
But when trying to connect it fails with an error complaining that the SERVICE_NAME was not provided.
ORA-12504: TNS:listener was not given the SERVICE_NAME in CONNECT_DATA
Oddly this works with cx_Oracle directly:
con = cx_Oracle.connect('user/pass#server:1521/dev')
How am I supposed to connect to the specific service?
Attempts
I have tried to use cx_Oracle.makedsn() explicitly from this question with no luck as well.
Trying to use ? options in the connection string
oracle_db = sqlalchemy.create_engine('oracle://user:pass#server:1521/?sid=dev')
works initially but when I try oracle_db.connect() I get the same ORA-12504 error shown above.

Based on the documentation at Sqlalchemy Documentation, you should probably use the cx_oracle engine. The connect string is:
oracle+cx_oracle://user:pass#host:port/dbname[?key=value&key=value...]
with an option of service_name or sid as follows:
oracle+cx_oracle://user:pass#host:1521/?service_name=hr
oracle+cx_oracle://user:pass#host:1521/?sid=hr

Try using this connection string:
engine = create_engine("oracle+cx_oracle://<username>:<password>#(DESCRIPTION = (LOAD_BALANCE=on) (FAILOVER=ON) (ADDRESS = (PROTOCOL = TCP)(HOST = <host>)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = devdb)))")
It worked for me.

cx_Oracle doesn't connect when using SID instead of service name on connection string

I have a connection string that looks like this
con_str = "myuser/mypass#oracle.sub.example.com:1521/ora1"
Where ora1 is the SID of my database. Using this information in SQL Developer works fine, meaning that I can connect and query without problems.
However, if I attempt to connect to Oracle using this string, it fails.
cx_Oracle.connect(con_str)
DatabaseError: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor
This connection string format works if the ora1 is a service name, though.
I have seen other questions that seem to have the reverse of my problem (it works with SID, but not Service name)
Using Oracle Service Names with SQLAlachemy
Oracle SID and Service name; connection problems
cx_Oracle & Connecting to Oracle DB Remotely
What is the proper way to connect to Oracle, using cx_Oracle, using an SID and not a service name? How do I do this without the need to adjust the TNSNAMES.ORA file? My application is distributed to many users internally and making changes to the TNSNAMES file is less than ideal when dealing with users without administrator privileges on their Windows machines. Additionally, when I use service name, I don't need to touch this file at all and would like it keep it that way.

I a similar scenario, I was able to connect to the database by using cx_Oracle.makedsn() to create a dsn string with a given SID (instead of the service name):
dsnStr = cx_Oracle.makedsn("oracle.sub.example.com", "1521", "ora1")
This returns something like
(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=oracle.sub.example.com)(PORT=1521)))(CONNECT_DATA=(SID=ora1)))
which can then be used with cx_Oracle.connect() to connect to the database:
con = cx_Oracle.connect(user="myuser", password="mypass", dsn=dsnStr)
print con.version
con.close()

For those looking for how to specify service_name instead of SID.
From changelog for SQLAlchemy 1.0.0b1 (released on March 13, 2015):
[oracle] [feature] Added support for cx_oracle connections to a
specific service name, as opposed to a tns name, by passing
?service_name=<name> to the URL. Pull request courtesy Sławomir
Ehlert.
The change introduces new, Oracle dialect specific option service_name which can be used to build connect string like this:
from sqlalchemy import create_engine
from sqlalchemy.engine import url
connect_url = url.URL(
'oracle+cx_oracle',
username='some_username',
password='some_password',
host='some_host',
port='some_port',
query=dict(service_name='some_oracle_service_name'))
engine = create_engine(connect_url)

If you are using sqlalchemy and ORACLE 12, the following seems to work.
from sqlalchemy import create_engine
con='oracle://user:password#hostname:1521/?service_name=DDDD'
engine = create_engine(con)
Note, you have to use the service name and not the SID. I don't know why, but the simple connection string that uses SID does not work.

It still may not work. You need to take the output of dsnStr and modify the string by replacing SID with SERVICE_NAME and use that variable in the con string. This procedure worked for me.

SID's may not be easily accessible or you might not have it created for your database.
In my case, I'm working from the client side requesting access to a cloud database so creating an SID didn't really make sense.
Instead, you might have a string that looks similar to this:
"(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = something.cloud.company)
(PORT = 12345)) (ADDRESS = (PROTOCOL = TCP)(HOST = something.cloud.company)
(PORT = 12345)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME =
something.company)))"
You can use it in replacement of the SID.
connection = cx_Oracle.connect("username", "pw", "(DESCRIPTION = (ADDRESS =
(PROTOCOL = TCP)(HOST = something.cloud.company)(PORT = 12345)) (ADDRESS =
(PROTOCOL = TCP)(HOST = something.cloud.company)(PORT = 12345))
(CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = something.company)))")

I thought during a while that I would not be able to use Magic SQL (%sql, %%sql) because of service name issue in connection that would force to use the alternative way described above with cx_Oracle.connect(), cx_Oracle.makedsn()... I finally found a solution working for me: declare and set a variable for the service name first and then use it in the command (since not working if literal string for service name put in the command !)
import cx_Oracle
user='youruser'
pwd='youruserpwd'
dbhost='xx.xx.xx.xx'
service='yourservice'
%load_ext sql
%sql oracle+cx_oracle://$user:$pwd#$dbhost:1521/?service_name=$service
output (what you get in successful connection):
u'Connected: youruser#'

If someone is looking to set oracle.jdbc.proxyClientName property for cx_oracle, to connect using proxyClient, they can use -
cx_Oracle.init_oracle_client("../../oracle_local_client", config_dir= "../../oracle_local_client/network/admin")
connectDsn = cx_Oracle.makedsn('db.svr.net', 'portNumberHere',service_name="TEST_READWRITE")
#replace all prams above
pool = cx_Oracle.SessionPool(externalauth=True, homogeneous=False, dsn = connectDsn)
connection = pool.acquire(user="[PROXY_CLIENT_NAME]")
Notice the use of '[' braces to depict that the user is proxyClient.
I am using Kerberos authentication for this and my SQLNET.ora file contains the below properties.
NAMES.DIRECTORY_PATH=(TNSNAMES,HOSTNAME,EZCONNECT)
SQLNET.AUTHENTICATION_SERVICES = (BEQ,KERBEROS5PRE,KERBEROS5)
SQLNET.AUTHENTICATION_KERBEROS5_SERVICE=oracle
SQLNET.KERBEROS5_CC_NAME=OSMSFT:
SQLNET.KERBEROS5_CONF_MIT=TRUE
SQLNET.KERBEROS5_CONF=I:\projects\poc\resources\krb5.conf # krb5 config file complete path.
For more information, refer the video embedded in this article.

I also met this issue.
The solution is:
1: get the service name at tnsnames.ora
2: put the service name in
con_str = "myuser/mypass#oracle.sub.example.com:1521/ora1"