oncall-engine/engine/apps/alerts/paging.py

import typing
from uuid import uuid4

from django.db import transaction

from apps.alerts.models import (
    Alert,
    AlertGroup,
    AlertGroupLogRecord,
    AlertReceiveChannel,
    ChannelFilter,
    UserHasNotification,
)
from apps.alerts.tasks.notify_user import notify_user_task
from apps.schedules.ical_utils import get_oncall_users_for_multiple_schedules
from apps.schedules.models import OnCallSchedule
from apps.user_management.models import Organization, Team, User

UserNotifications = list[tuple[User, bool]]


class DirectPagingAlertGroupResolvedError(Exception):
    """Raised when trying to use direct paging for a resolved alert group."""

    DETAIL = "Cannot add responders for a resolved alert group"  # Returned in BadRequest responses and Slack warnings


class DirectPagingUserTeamValidationError(Exception):
    """Raised when trying to use direct paging and no team or user is specified."""

    DETAIL = "No team or user(s) specified"  # Returned in BadRequest responses and Slack warnings


class _OnCall(typing.TypedDict):
    title: str
    message: str
    uid: str
    author_username: str
    permalink: str


class DirectPagingAlertPayload(typing.TypedDict):
    oncall: _OnCall


def _trigger_alert(
    organization: Organization, team: Team | None, message: str, title: str, from_user: User
) -> AlertGroup:
    """Trigger manual integration alert from params."""
    alert_receive_channel = AlertReceiveChannel.get_or_create_manual_integration(
        organization=organization,
        team=team,
        integration=AlertReceiveChannel.INTEGRATION_DIRECT_PAGING,
        deleted_at=None,
        defaults={
            "author": from_user,
            "verbal_name": f"Direct paging ({team.name if team else 'No'} team)",
        },
    )

    channel_filter = None
    if alert_receive_channel.default_channel_filter is None:
        channel_filter = ChannelFilter.objects.create(
            alert_receive_channel=alert_receive_channel,
            notify_in_slack=True,
            is_default=True,
        )

    payload: DirectPagingAlertPayload = {
        # Custom oncall property in payload to simplify rendering
        "oncall": {
            "title": title,
            "message": message,
            "uid": str(uuid4()),  # avoid grouping
            "author_username": from_user.username,
            "permalink": None,
        },
    }

    alert = Alert.create(
        title=title,
        message=message,
        alert_receive_channel=alert_receive_channel,
        raw_request_data=payload,
        integration_unique_data={"created_by": from_user.username},
        image_url=None,
        link_to_upstream_details=None,
        channel_filter=channel_filter,
    )
    return alert.group


def _construct_title(from_user: User, team: Team | None, users: UserNotifications) -> str:
    title = f"{from_user.username} is paging"

    names = [team.name] if team is not None else []
    names.extend([user.username for user, _ in users])

    if (num_names := len(names)) == 1:
        title += f" {names[0]}"
    elif num_names > 1:
        title += f" {', '.join(names[:-1])} and {names[-1]}"

    title += " to join escalation"

    return title


def direct_paging(
    organization: Organization,
    from_user: User,
    message: str,
    title: str | None = None,
    team: Team | None = None,
    users: UserNotifications | None = None,
    alert_group: AlertGroup | None = None,
) -> AlertGroup | None:
    """Trigger escalation targeting given team/users.

    If an alert group is given, update escalation to include the specified users.
    Otherwise, create a new alert using given message.
    """
    if users is None:
        users = []

    if not users and team is None:
        raise DirectPagingUserTeamValidationError

    # Cannot add responders to a resolved alert group
    if alert_group and alert_group.resolved:
        raise DirectPagingAlertGroupResolvedError

    if title is None:
        title = _construct_title(from_user, team, users)

    # create alert group if needed
    if alert_group is None:
        alert_group = _trigger_alert(organization, team, message, title, from_user)

    for u, important in users:
        alert_group.log_records.create(
            type=AlertGroupLogRecord.TYPE_DIRECT_PAGING,
            author=from_user,
            reason=f"{from_user.username} paged user {u.username}",
            step_specific_info={
                "user": u.public_primary_key,
                "important": important,
            },
        )
        notify_user_task.apply_async(
            (u.pk, alert_group.pk), {"important": important, "notify_even_acknowledged": True, "notify_anyway": True}
        )

    return alert_group


def unpage_user(alert_group: AlertGroup, user: User, from_user: User) -> None:
    """
    Remove user from alert group escalation.

    An IndexError is raised (and caught) if the user had not been notified for some reason.
    Regardless of whether or not the user was notified, we will always create an AlertGroupLogRecord of type
    TYPE_UNPAGE_USER.
    """
    try:
        with transaction.atomic():
            user_has_notification = UserHasNotification.objects.filter(
                user=user, alert_group=alert_group
            ).select_for_update()[0]
            user_has_notification.active_notification_policy_id = None
            user_has_notification.save(update_fields=["active_notification_policy_id"])
    except IndexError:
        return
    finally:
        alert_group.log_records.create(
            type=AlertGroupLogRecord.TYPE_UNPAGE_USER,
            author=from_user,
            reason=f"{from_user.username} unpaged user {user.username}",
            step_specific_info={"user": user.public_primary_key},
        )


def user_is_oncall(user: User) -> bool:
    schedules_with_oncall_users = get_oncall_users_for_multiple_schedules(OnCallSchedule.objects.related_to_user(user))
    return user.pk in {user.pk for _, users in schedules_with_oncall_users.items() for user in users}


def integration_is_notifiable(integration: AlertReceiveChannel) -> bool:
    """
    Returns true if:
    - the integration has more than one channel filter associated with it
    - the default channel filter has at least one notification method specified or an escalation chain associated with it
    """
    if integration.channel_filters.count() > 1:
        return True

    default_channel_filter = integration.default_channel_filter
    if not default_channel_filter:
        return False

    organization = integration.organization
    notify_via_slack = organization.slack_is_configured and default_channel_filter.notify_in_slack
    notify_via_telegram = organization.telegram_is_configured and default_channel_filter.notify_in_telegram

    notify_via_chatops = notify_via_slack or notify_via_telegram
    custom_messaging_backend_configured = default_channel_filter.notification_backends is not None

    return (
        default_channel_filter.escalation_chain is not None or notify_via_chatops or custom_messaging_backend_configured
    )