Problem:

• When using the service user auth and inserting / updating a calendar event, the reminders are not overridden
• The event is inserted / updated correct APART from the reminders are always at the default (email > 10m, popup > 30m).

Context:

• Node.js using standard libraries below
• Valid service account with downloaded credentials.json
• Service account (service-user-account@myapp.iam.gserviceaccount.com) has write access to myuser@gmail.com calendar

Code:

const {google} = require('googleapis')
const {auth} = require('google-auth-library')
const credentials = require('./credentials.json')

const addEvent = async (auth) => {
  const calendar = google.calendar({version: 'v3', auth})
  const insertRes = await calendar.events.insert({
    calendarId: 'myuser@gmail.com',
    resource: {
      summary: 'Test API',
      start: {
        dateTime: '2020-06-02T12:55:00.000',
        timeZone: 'Europe/London'
      },
      end: {
        dateTime: '2020-06-02T12:56:00.000',
        timeZone: 'Europe/London'
      },
      reminders: {
        useDefault: false,
        overrides: [
          {method: 'popup', 'minutes': 5}
        ]
      }
    }
  })
  console.log('insertRes', insertRes.data)
}

const getAuth = async () => {
  let client = auth.fromJSON(credentials)
  client.scopes = ['https://www.googleapis.com/auth/calendar', 'https://www.googleapis.com/auth/calendar.events']
  return client
}
const init = async () => {
  const auth = await getAuth()
  await addEvent(auth)
}
init()

Response: from console.log(insertRes)

{ kind: 'calendar#event',
  etag: '"3182200547452000"',
  id: '6063phndufgppo8rfev1XXXXXX',
  status: 'confirmed',
  htmlLink:
   'https://www.google.com/calendar/event?eid=NjA2M3BobmR1ZmdwcG84cmZldjFjdWh2YzQgZGFuZ2FyZmllbGR1a0Bnb29nbGVtYWlsXXXXXX',
  created: '2020-06-02T12:17:53.000Z',
  updated: '2020-06-02T12:17:53.768Z',
  summary: 'Test API',
  creator:
   { email: 'service-user-account@myapp.iam.gserviceaccount.com' },
  organizer: { email: 'myuser@googlemail.com', self: true },
  start:
   { dateTime: '2020-06-02T12:55:00+01:00',
     timeZone: 'Europe/London' },
  end:
   { dateTime: '2020-06-02T12:56:00+01:00',
     timeZone: 'Europe/London' },
  iCalUID: '6063phndufgppo8rfev1XXXXXX@google.com',
  sequence: 0,
  reminders: { useDefault: false, overrides: [{"method":"popup","minutes":5}] }
}

Hopefully someone can shed a light on the issue for me.

Thanks

It seems to be a bug, already reported on Google's Public Issue Tracker

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