[CASSANDRA-18547] Refactor cqlsh On/Off switch implementation and make the output consistent

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.0-alpha2, 5.0, 5.1
• Component/s: CQL/Interpreter
• Change Category: Semantic
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/b58d8f174d4c1017d54d4b8bdb8a0a6c592f1655

Test and Documentation Plan

1. Manually tested the three switches:
   • TRACING
   • EXPAND
   • PAGING
2. Ran pytests successfully
3. Ran pycodestyle  

• Assignee: Brad Schoening
• Reporter: Brad Schoening

Authors

Brad Schoening

Reviewers

Brandon Williams, Stefan Miklosovic

• Created: 24/May/23 03:02
• Updated: 01/Nov/23 08:54
• Resolved: 27/Sep/23 10:44

Description

This change refactors the On/Off switch implemented in the class SwitchCommand and subclass  SwitchCommandWithValue of cqlshmain.py to use an Enum with static methods instead of custom classes.

The body of on_off_switch + enum definition requires just 15 lines of code vs 33 in SwitchCommand.

The existing code is hard to read, including the usage in the code, which instantiates a SwitchCommand object in-order to invoke the execute method:

 

self.tracing_enabled = SwitchCommand("TRACING", "Tracing").execute(self.tracing_enabled, parsed, self.printerr)

this can be replaced by a more familiar direct function call:

self.tracing_enabled = self.on_off_toggle("TRACING", "Tracing", self.tracing_enabled, parsed.get_binding('switch'))

 

The refactoring also updates the command output for consistency. Instead of the current:

> tracing on
Now Tracing is enabled
> paging on
Query paging is already enabled. Use PAGING OFF to disable.
> expand on
Now Expanded output is enabled

replace with more succinct and consistent, using 'ON/OFF' instead of enabled/disabled and removing the redundant 'Now':

> tracing on
TRACING set to ON
> paging on
PAGING is already ON
> expand on
EXPAND set to ON

 

Issue Links

• is related to: CASSANDRA-18861 add time elapsed for simple CQL statement in the cql shell
• links to: dtest PR 232
• links to: GitHub Pull Request #2674
• links to: GitHub Pull Request #2679
• links to: PR 2674