fdbcli: Add documentation for setknob/getknob commands

design/dynamic-knobs.md

@@ -128,6 +128,35 @@ set_knob(db, 'min_trace_severity', '10', None, 'description')
 set_knob(db, 'min_trace_severity', '20', 'az-1', 'description')
 ```
 
+### CLI Usage
+
+Users may also utilize `fdbcli` to set and update knobs dynamically. Usage is as follows
+```
+setknob <knob_name> <knob_value> [config_class]
+getknob <knob_name> [config_class]
+```
+Where `knob_name` is an existing knob, `knob_value` is the desired value to set the knob and `config_class` is the optional configuration class. Furthermore, `setknob` may be combined within a `begin\commit` to update multiple knobs atomically. If using this option, a description must follow `commit` otherwise a prompt will be shown asking for a description. The description must be non-empty. An example follows.
+```
+begin
+setknob min_trace_severity 30
+setknob tracing_udp_listener_addr 192.168.0.1
+commit "fdbcli change"
+```
+Users may only combine knob configuration changes with other knob configuration changes in the same transaction. For example, the following is not permitted and will raise an error.
+```
+begin
+set foo bar
+setknob max_metric_size 1000
+commit "change"
+```
+Specifically, `set, clear, get, getrange, clearrange` cannot be combined in any transaction with a `setknob` or `getknob`.
+
+If using an individual `setknob` without being inside a `begin\commit` block, then `fdbcli` will prompt for a description as well.
+
+#### Type checking
+Knobs have implicit types attached to them when defined. For example, the knob `tracing_udp_listener_addr` is set to `"127.0.0.1"` as so the type is string. If a user invokes `setknob` on this knob with an incorrect value that is not a string, the transaction will fail. 
+
+
 ### Disable the Configuration Database
 
 The configuration database includes both client and server changes and is

documentation/sphinx/source/command-line-interface.rst

@@ -203,6 +203,13 @@ The ``get`` command fetches the value of a given key. Its syntax is ``get <KEY>`
 
 Note that :ref:`characters can be escaped <cli-escaping>` when specifying keys (or values) in ``fdbcli``.
 
+getknob
+-------
+
+The ``getknob`` command fetches the value of a given knob that has been populated by ``setknob``. Its syntax is ``getknob <KNOBNAME> [CONFIGCLASS]``. It displays the value of ``<KNOBNAME>`` if ``<KNOBNAME>`` is present in the database and ``not found`` otherwise.
+
+Note that :ref:`characters can be escaped <cli-escaping>` when specifying keys (or values) in ``fdbcli``.
+
 getrange
 --------
 
@@ -395,6 +402,13 @@ The ``setclass`` command can be used to change the :ref:`process class <guidelin
 
 The available process classes are ``unset``, ``storage``, ``transaction``, ``resolution``, ``grv_proxy``, ``commit_proxy``, ``master``, ``test``, ``unset``, ``stateless``, ``log``, ``router``, ``cluster_controller``, ``fast_restore``, ``data_distributor``, ``coordinator``, ``ratekeeper``, ``storage_cache``, ``backup``, and ``default``.
 
+setknob
+-------
+
+The ``setknob`` command can be used to set knobs dynamically. Its syntax is ``setknob <KNOBNAME> <KNOBVALUE> [CONFIGCLASS]``. If not present in a ``begin\commit`` block, the CLI will prompt for a description of the change. 
+
+Note that :ref:`characters can be escaped <cli-escaping>` when specifying keys (or values) in ``fdbcli``.
+
 sleep
 -----
 

fdbcli/tests/fdbcli_tests.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
 
-from cProfile import run
 import sys
 import shutil
 import os