Feed silence for AI agents

# -*- coding: utf-8 -*-

# stdlib
from datetime import datetime

# Zato
from zato.common.audit_log.api import AuditSource
from zato.server.service import Service

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# The feed-silence threshold in minutes.
_silence_threshold_minutes = 30

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class FeedSilence(Service):
    """ Returns, per interface, when its last HL7 message arrived and
    whether the interface has been silent for longer than the threshold.
    """
    name = 'interface.feed-silence'

    output = 'threshold_minutes', 'has_silent_feeds', 'interfaces'

    def handle(self) -> 'None':

        # Get the newest event time of each HL7 channel ..
        last_seen = self.audit.last_seen(AuditSource.MLLP_Channel)

        # .. establish the comparison time and response accumulators ..
        now = datetime.now()
        interfaces = []
        has_silent_feeds = False

        # .. compare each interface against the silence threshold ..
        for interface, last_received_at_iso in sorted(last_seen.items()):

            # .. compute how long ago its last message arrived ..
            last_received_at = datetime.fromisoformat(last_received_at_iso)
            since_last = now - last_received_at
            minutes_since_last = int(since_last.total_seconds() / 60)

            # .. check whether that exceeds the threshold ..
            is_silent = minutes_since_last > _silence_threshold_minutes

            # .. retain whether any interface exceeded it ..
            if is_silent:
                has_silent_feeds = True

            # .. add the status of this interface to the result ..
            interfaces.append({
                'interface': interface,
                'last_received_at': last_received_at_iso,
                'minutes_since_last': minutes_since_last,
                'is_silent': is_silent,
            })

        # .. and return the declared tool response.
        self.response.payload = {
            'threshold_minutes': _silence_threshold_minutes,
            'has_silent_feeds': has_silent_feeds,
            'interfaces': interfaces,
        }