DOCSP-20089 Add documentation around HTTP Proxy support (#665)

* DOCSP-20089 Add documentation around HTTP Proxy support

* DOCSP-20089 updates for copy review feedback

* DOCSP-20089 updates for review feedback

* DOCSP-20089 updates to add example

* DOCSP-20089 updates for feedback

Author: kanchana-mongodb

source/configure.txt

@@ -22,9 +22,45 @@ Configure the {+mcli+}
 
 You can define the settings that the {+mcli+} uses to interact with
 MongoDB services like |service|, |cloud-short|, and |onprem| by using
-the :ref:`mongocli-auth-login` or :ref:`mongocli-config` commands.
-The first time you run one of these commands, the {+mcli+} creates a :ref:`configuration file
-<mcli-config-file>` called ``mongocli.toml`` to store your settings.
+the :ref:`mongocli-auth-login` or :ref:`mongocli-config` command. The 
+first time you run one of these commands, the {+mcli+} creates a 
+:ref:`configuration file <mcli-config-file>` called ``mongocli.toml`` 
+to store your settings. 
+
+Prerequisites
+-------------
+
+To configure the {+mcli+}:
+
+- Add your |ipaddr| or |cidr| block to the |api| whitelist for your
+  MongoDB service.
+- Generate a |svc-api-key| if you don't already have one.
+  
+  .. note::
+
+     |svc-api-key|\s are role-based. Different roles have different
+     privileges and capabilities, and some {+mcli+} commands are available
+     to some roles but not others. Be sure that the roles assigned to
+     your |svc-api-key| are appropriate for the commands you intend to
+     use.
+
+  To learn more about generating a |svc-api-key| for
+  your MongoDB service, see the following documentation:
+
+  - :atlas:`Atlas API Access </configure-api-access>`
+  - :cloudmgr:`Cloud Manager API Access </tutorial/configure-public-api-access>`
+  - :opsmgr:`Ops Manager API Acess </tutorial/configure-public-api-access>`
+
+- Set up the ``HTTP_PROXY`` or ``HTTPS_PROXY`` :ref:`environment 
+  variable <mcli-env-var>` if your {+mcli+} installation is behind a 
+  firewall and you want to use a proxy |url|. {+mcli+} supports 
+  ``http``, ``https``, and ``socks5`` schemes. In addition, specify 
+  ``cloud.mongodb.com/`` as the main target URL in the proxy service's 
+  access list. You must specify the username and password also if your 
+  proxy configuration enables authentication. 
+  
+  To learn more, see `Proxy server 
+  <https://en.wikipedia.org/wiki/Proxy_server>`__.
 
 Procedure
 ---------

source/configure/environment-variables.txt

@@ -129,3 +129,52 @@ The {+mcli+} supports the following environment variables:
 
           Setting ``MCLI_OPS_MANAGER_SKIP_VERIFY`` to ``yes`` is
           insecure and is not recommended in production environments.
+
+   * - ``HTTP_PROXY``, ``http_proxy``
+     - The absolute |url| or the hostname and port in the 
+       ``hostname[:port]`` format. 
+
+       .. example:: 
+
+          The following example shows how to set up the environment 
+          variable if your proxy configuration doesn't require 
+          authentication.
+
+          .. code-block:: sh 
+             :copyable: false 
+
+             HTTP_PROXY=<my.proxy.address>
+
+          The following example shows how to set up the environment 
+          variable if your proxy configuration requires authentication.
+
+          .. code-block:: sh 
+             :copyable: false 
+
+             HTTP_PROXY=username:password@<my.proxy.address>
+
+          The following example shows how to set up the environment 
+          variable if the scheme is ``socks5``.
+
+          .. code-block:: sh 
+             :copyable: false 
+
+             HTTP_PROXY=socks5://<my.proxy.address>
+
+   * - ``HTTPS_PROXY``, ``https_proxy``
+     - The absolute |url|. If ``HTTP_PROXY`` is also set, this takes 
+       precedence over ``HTTP_PROXY`` for all requests.
+
+       .. example:: 
+
+          The following example shows how to set up the environment 
+          variable.
+
+          .. code-block:: sh 
+             :copyable: false 
+
+             HTTPS_PROXY=https://<my.proxy.address>
+
+   * - ``NO_PROXY``, ``no_proxy``
+     - Indicates no proxy for the |url| because proxy isn't configured 
+       for the |url|.