Only when trying to connect to my Azure DB from Python 3.7 running in a OpenShift container (FROM rhel7:latest) I see the following error:
sqlalchemy.exc.DBAPIError: (pyodbc.Error) ('IM004', "[IM004][unixODBC][Driver Manager]Driver's SQLAllocHandle on SQL_HANDLE_HENV failed (0) (SQLDriverConnect)
I tried the exact same code in Docker on my MAC, Windows and a RHEL7 Virtualbox running the RHEL7 base container - it always works! The problem is only in my container running in OpenShift! I checked that I can telnet to my Azure DB server in 1433 from Openshift.
I enabled the ODBC logs as well but there is no more information than the above error.
What else should I check?
Here is how I set up the MSODBC driver in my Dockerfile:
RUN curl https://packages.microsoft.com/config/rhel/7/prod.repo > /etc/yum.repos.d/mssql-release.repo && \
yum remove unixODBC-utf16 unixODBC-utf16-devel && \
ACCEPT_EULA=Y yum install -y msodbcsql17 && \
yum install -y unixODBC-devel
And here is the code that throws the error:
inside modules.database:
pyodbc_connstring_safe = 'DRIVER={{ODBC Driver 17 for SQL Server}};SERVER='+config.settings["DB_HOST"]+\
';PORT=1433;DATABASE='+config.settings["DB_NAME"]+';UID='+config.usernames["database"]+\
';PWD={};MARS_Connection=Yes'
if config.settings["debug"]:
print("Using DB connection string: {}".format(pyodbc_connstring_safe.format("SAFE_DB_PASS")))
pyodbc_connstring = pyodbc_connstring_safe.format(config.passwords["database"])
Base = declarative_base()
quoted = urllib.parse.quote_plus(pyodbc_connstring)
def get_engine():
return create_engine('mssql+pyodbc:///?odbc_connect={}'.format(quoted), echo=config.settings["debug"], pool_pre_ping=True)
Inside my flask app (the error gets thrown in the call to 'has_table'):
@app.route("/baselinedb", methods=["POST"])
def create_db():
from modules.database import Base
engine = database.get_engine()
if not engine.dialect.has_table(engine, database.get_db_object_name("BaselineDefinition"), schema = 'dbo'):
Base.metadata.create_all(engine)
db.session.commit()
return "OK"
As I mentioned in the beginning, the same Dockerfile gives me a working Container in Docker either locally on Mac or Windows or inside a RHEL7 VM. Thanks for having a look!
unixODBC is trying to find the odbc.ini in the current users home directory. It's trying to do this by looking up the user in /etc/passwd. Since Openshift is using a project specific UID which does not exist in /etc/passwd the user lookup will not work and the connection will fail.
To resolve this add the following to the dockerfile
And the following in the entrypoint script
The above will insert the current user to /etc/passwd during startup of the container.
An alternative and probably better approach might be to use nss_wrapper: https://cwrap.org/nss_wrapper.html