Remove environment variable configuration for usage tracking (#3466)

This PR removes the use of $PARSL_TRACKING env variable to setup usage tracking configuration. Parsl will now only take usage tracking configuration from the config

Anyone using only the env variable PARSL_TRACKING to enable usage tracking will need to set usage_tracking = True within the config to enable usage tracking.

docs/quickstart.rst

@@ -236,8 +236,7 @@ for reporting purposes.
 
 As an NSF-funded project, our ability to track usage metrics is important for continued funding. 
 
-You can opt-in by setting ``PARSL_TRACKING=true`` in your environment or by 
-setting ``usage_tracking=True`` in the configuration object (`parsl.config.Config`). 
+You can opt-in by setting ``usage_tracking=True`` in the configuration object (`parsl.config.Config`). 
 
 To read more about what information is collected and how it is used see :ref:`label-usage-tracking`.
 

docs/userguide/usage_tracking.rst

@@ -32,7 +32,7 @@ will choose to send us this information. The reason is that we need this data -
 By opting-in, and allowing these statistics to be reported back, you are explicitly supporting the
 further development of Parsl.
 
-If you wish to opt in to usage reporting, set ``PARSL_TRACKING=true`` in your environment or set ``usage_tracking=True`` in the configuration object (`parsl.config.Config`).
+If you wish to opt in to usage reporting, set ``usage_tracking=True`` in the configuration object (`parsl.config.Config`).
 
 
 .. _what-is-sent:

parsl/usage_tracking/usage.py

@@ -1,6 +1,5 @@
 import json
 import logging
-import os
 import platform
 import socket
 import sys
@@ -117,22 +116,12 @@ def __init__(self, dfk, port=50077,
  def check_tracking_enabled(self):
  """Check if tracking is enabled.
 
- Tracking will be enabled unless either of these is true:
+ Tracking will be enabled unless the following is true:
 
  1. dfk.config.usage_tracking is set to False
- 2. Environment variable PARSL_TRACKING is set to false (case insensitive)
 
  """
- track = True
-
- if not self.config.usage_tracking:
- track = False
-
- envvar = str(os.environ.get("PARSL_TRACKING", True)).lower()
- if envvar == "false":
- track = False
-
- return track
+ return self.config.usage_tracking
 
  def construct_start_message(self) -> bytes:
  """Collect preliminary run info at the start of the DFK.