Using PyMongo with MongoDB Atlas
================================

`Atlas <https://www.mongodb.com/cloud>`_ is MongoDB, Inc.'s hosted MongoDB as a
service offering. To connect to Atlas, pass the connection string provided by
Atlas to :class:`~pymongo.mongo_client.MongoClient`::

  client = pymongo.MongoClient(<Atlas connection string>)

Connections to Atlas require TLS/SSL. For connections using TLS/SSL, PyMongo
may require third party dependencies as determined by your version of Python.
With PyMongo 3.3+, you can install PyMongo 3.3+ and any TLS/SSL-related
dependencies using the following pip command::

  $ python -m pip install pymongo[tls]

Starting with PyMongo 3.11 this installs `PyOpenSSL
<https://pypi.org/project/pyOpenSSL/>`_, `requests`_
and `service_identity
<https://pypi.org/project/service_identity/>`_
for users of Python versions older than 2.7.9. PyOpenSSL supports SNI for these
old Python versions, allowing applictions to connect to Altas free and shared
tier instances.

Earlier versions of PyMongo require you to manually install the dependencies.
For a list of TLS/SSL-related dependencies, see :doc:`examples/tls`.

.. note:: Connecting to Atlas "Free Tier" or "Shared Cluster" instances
  requires Server Name Indication (SNI) support. SNI support requires CPython
  2.7.9 / PyPy 2.5.1 or newer or PyMongo 3.11+ with PyOpenSSL.
  To check if your version of Python supports SNI run the following command::

    $ python -c "import ssl; print(getattr(ssl, 'HAS_SNI', False))"

  You should see "True".

.. warning:: Industry best practices recommend, and some regulations require,
  the use of TLS 1.1 or newer. Though no application changes are required for
  PyMongo to make use of the newest protocols, some operating systems or
  versions may not provide an OpenSSL version new enough to support them.

  Users of macOS older than 10.13 (High Sierra) will need to install Python
  from `python.org`_, `homebrew`_, `macports`_, or another similar source.

  Users of Linux or other non-macOS Unix can check their OpenSSL version like
  this::

    $ openssl version

  If the version number is less than 1.0.1 support for TLS 1.1 or newer is not
  available. Contact your operating system vendor for a solution or upgrade to
  a newer distribution.

  You can check your Python interpreter by installing the `requests`_ module
  and executing the following command::

    python -c "import requests; print(requests.get('https://www.howsmyssl.com/a/check', verify=False).json()['tls_version'])"

  You should see "TLS 1.X" where X is >= 1.

  You can read more about TLS versions and their security implications here:

  `<https://www.owasp.org/index.php/Transport_Layer_Protection_Cheat_Sheet#Rule_-_Only_Support_Strong_Protocols>`_

.. _python.org: https://www.python.org/downloads/
.. _homebrew: https://brew.sh/
.. _macports: https://www.macports.org/
.. _requests: https://pypi.python.org/pypi/requests

