Log telemetry events into separate log file and the output channels for logs

[ramya-rao-a]

At present, there is no way for a user to know what telemetry events are being logged in VS Code other than searching the code base for telemetryService.publicLog. Event after doing so, its never clear what data is exactly being sent. In order to be transparent, we need to have a dedicated place where the user can see all the telemetry events being logged along with the data being sent.

The output channels for the logs (when in trace mode) from various processes (main, shared, renderer) can also benefit from the inclusion of the telemetry events (with common data removed to reduce noise) as this will help the development/debugging process.

[ramya-rao-a]

Here is my proposal:

When the log level is changed to trace or VS Code is started in the cli with --verbose option

• The telemetry events for the main, renderer, shared and issue reporter processes will appear in the respective log files with reduced content (event name + data without noise from common data). Use Developer: Open Log File to open the log files.
• The above will also appear in corresponding output channels Log (Main), Log (Window) and Log (Shared).
• All telemetry events (other than the ones from cli process) with all data is logged to a new dedicated file telemetry.log. This file will live in the same place as other log files and can be opened using the Open Log File command.
• The telemetry events from the cli process will be included in the cli.log file (this is the existing file that has logs from the cli process) when started using the --verbose flag

Note: This does not include telemetry events sent from extensions.

[ramya-rao-a]

Re-opening to investigate logging telemetry events from extensions that use our vscode-extension-telemetry module to send telemetry

[jens1o]

Finally. :)

[ramya-rao-a]

With microsoft/vscode-extension-telemetry#21, the built-in extensions will also log the telemetry events to log files in the same folder as rest of the log files when VS Code is started in --verbose mode.

#55398 tracks the feature request to enable the same when VS Code is started normally and the log level then changed to trace