Problem

When creating a recurring event via gog calendar create with --rrule, the Google Calendar API returns:

Google API error (400 required): Missing time zone definition for start time.

This happens because Google requires an explicit TimeZone field on the EventDateTime struct for recurring events.

Solution

Extract the timezone from the RFC3339 offset in the --from/--to values and map common offsets to IANA timezone names.

Example

This now works:

gog calendar create primary \
  --summary 'Publix Pharmacy App Order' \
  --from '2026-01-08T11:00:00-05:00' \
  --to '2026-01-08T11:30:00-05:00' \
  --rrule 'RRULE:FREQ=DAILY;INTERVAL=28' \
  --account user@example.com

Notes

• Maps common US timezone offsets (-8 to -4) to IANA names
• UTC (Z suffix or +00:00) is handled
• Unknown offsets gracefully degrade (no timezone set, non-recurring events still work)
• Added unit tests for extractTimezone()