bug: pagerduty_plugin - Updates method for accessing current on-call email

[Meandmybadself]

Issue

The existing get_oncall_email method assumes that there is only one associated schedule with an on-call escalation policy. In the event that more than one schedule exists (say, if there is a US and India team) and the second schedule is active, the method will attempt to find the on-call engineer in the first schedule & fail.

Resolution

This fix updates the method to iterate over all escalation_rules in an attempt to find the on-call engineer. Only after it has iterated over all schedules and not found an engineer will it throw an Exception.

Example of multi-schedule API response

{
        "description": "",
        "escalation_rules": [
                {
                        "escalation_delay_in_minutes": 30,
                        "id": "IDREDACTED",
                        "targets": [
                                {
                                        "html_url": "https://company.pagerduty.com/schedules/IDREDACTED",
                                        "id": "IDREDACTED",
                                        "self": "https://api.pagerduty.com/schedules/IDREDACTED",
                                        "summary": "Data Team - India On Call",
                                        "type": "schedule_reference"
                                },
                                {
                                        "html_url": "https://company.pagerduty.com/schedules/IDREDACTED",
                                        "id": "IDREDACTED",
                                        "self": "https://api.pagerduty.com/schedules/IDREDACTED",
                                        "summary": "Data Team - US On Call",
                                        "type": "schedule_reference"
                                }
                        ]
                }
        ]
}