power

// The power of a server, by the Redfish service of its management card (DMTF Redfish): the health of each
// power supply and of their redundancy, and the power the chassis draws. Any card that serves Redfish: Dell
// iDRAC, HPE iLO, Supermicro, Lenovo XCC, OpenBMC.
// A chassis is read by its Power resource, which the cards serve, deprecated since schema 2020.4; a chassis
// that serves only the PowerSubsystem of the later schemas is read by it. Power is preferred when both are
// served: it gives the power drawn in the same resource.
need('protocol:http');
$address = need('host:address');
$user = need('protocol:http:user');
$password = need('protocol:http:password');

per('component', 'Components');
output('health', 'text', array('label' => 'Health', 'per' => 'component'));
output('consumption', 'number', array('label' => 'Power drawn', 'unit' => 'W', 'per' => 'component'));

watch.state('unhealthy', 'Power supply or redundancy degraded', 'health', array('warning' => array('warning'), 'critical' => array('critical')));
watch.above('consumption', 'High power drawn', 'consumption', array(
    'help'    => 'Raises above the power set on the probe, in watts, for the chassis.',
    'enabled' => false,
));
watch.missing('missing', 'Power supply missing', 'health', array('enabled' => false));

// Returns one Redfish resource, read by its path (/redfish/v1/...), the account in Basic. The password only
// goes in the Basic header: the answer is not secret.
function redfish_get($address, $path, $user, $password) {
    $answer = http.get('https://' . $address . $path, headers=array('Accept' => 'application/json'), user=$user, password=$password);
    if ($answer['status'] == 401 || $answer['status'] == 403) {
        fail('misconfigured', 'The Redfish service refuses the account, code ' . $answer['status'], $path);
    }
    if ($answer['status'] != 200) {
        fail('unreachable', 'The Redfish service answers code ' . $answer['status'], $path);
    }
    return json.read($answer['body']);
}

// Returns the health of a resource, in lower case (ok, warning, critical): the health it rolls up from what
// is under it when it gives one, its own otherwise, unknown when it gives neither.
function health_of($resource) {
    $status = list.get($resource, 'Status', array());
    $health = list.get($status, 'HealthRollup', '');
    if ($health == '') {
        $health = list.get($status, 'Health', '');
    }
    if ($health == '') {
        return 'unknown';
    }
    return text.lower($health);
}

// Returns the instance name of each item: its name, or, when another item bears the same name (HPE iLO
// calls every power supply alike), its name followed by its id.
function instance_names($items) {
    $counts = array();
    foreach ($items as $item) {
        $counts[$item['name']] = list.get($counts, $item['name'], 0) + 1;
    }
    $names = array();
    foreach ($items as $key => $item) {
        $names[$key] = $item['name'];
        if ($item['name'] == '' || $counts[$item['name']] > 1) {
            $names[$key] = text.trim($item['name'] . ' ' . $item['id']);
        }
        // A card that gives neither a name nor an id (both null, read as '').
        if ($names[$key] == '') {
            $names[$key] = 'unnamed ' . ($key + 1);
        }
    }
    return $names;
}

// Each power supply and each redundancy group, as array('name', 'id', 'health'); the power drawn, by chassis.
$items = array();
$drawn = array();
$chassis_list = redfish_get($address, '/redfish/v1/Chassis', $user, $password);
foreach (list.get($chassis_list, 'Members', array()) as $member) {
    $chassis = redfish_get($address, $member['@odata.id'], $user, $password);
    $chassis_id = list.get($chassis, 'Id', $member['@odata.id']);

    // Power: {"PowerSupplies": [{"MemberId": "0", "Name": "PS1", "Status": {"State": "Enabled", "Health":
    // "OK"}}], "Redundancy": [{"MemberId": "0", "Name": "PSU Redundancy", "Mode": "N+m", "Status": {...}}],
    // "PowerControl": [{"PowerConsumedWatts": 212}]}. A supply the card says absent is an empty bay.
    if (list.has($chassis, 'Power')) {
        $power = redfish_get($address, $chassis['Power']['@odata.id'], $user, $password);
        foreach (list.get($power, 'PowerSupplies', array()) as $supply) {
            if (list.get(list.get($supply, 'Status', array()), 'State', '') == 'Absent') {
                continue;
            }
            $items = list.add($items, array('name' => list.get($supply, 'Name', 'Power supply'),
                'id' => list.get($supply, 'MemberId', ''), 'health' => health_of($supply)));
        }
        foreach (list.get($power, 'Redundancy', array()) as $group) {
            $items = list.add($items, array('name' => list.get($group, 'Name', 'Redundancy'),
                'id' => list.get($group, 'MemberId', ''), 'health' => health_of($group)));
        }
        $watts = 0;
        $measured = false;
        foreach (list.get($power, 'PowerControl', array()) as $control) {
            if (list.get($control, 'PowerConsumedWatts', '') != '') {
                $watts = $watts + $control['PowerConsumedWatts'];
                $measured = true;
            }
        }
        if ($measured) {
            $drawn['chassis ' . $chassis_id] = $watts;
        }
    } elseif (list.has($chassis, 'PowerSubsystem')) {
        // PowerSubsystem: {"PowerSupplies": {"@odata.id": ".../PowerSupplies"}, "PowerSupplyRedundancy":
        // [{"RedundancyType": "NPlusM", "Status": {...}}]}; each power supply a resource of its own. The power
        // drawn is in the chassis' EnvironmentMetrics: {"PowerWatts": {"Reading": 212}}.
        $subsystem = redfish_get($address, $chassis['PowerSubsystem']['@odata.id'], $user, $password);
        if (list.has($subsystem, 'PowerSupplies')) {
            $supplies = redfish_get($address, $subsystem['PowerSupplies']['@odata.id'], $user, $password);
            foreach (list.get($supplies, 'Members', array()) as $link) {
                $supply = redfish_get($address, $link['@odata.id'], $user, $password);
                if (list.get(list.get($supply, 'Status', array()), 'State', '') == 'Absent') {
                    continue;
                }
                $items = list.add($items, array('name' => list.get($supply, 'Name', 'Power supply'),
                    'id' => list.get($supply, 'Id', ''), 'health' => health_of($supply)));
            }
        }
        $number = 0;
        foreach (list.get($subsystem, 'PowerSupplyRedundancy', array()) as $group) {
            $number = $number + 1;
            $items = list.add($items, array('name' => 'Redundancy ' . $number, 'id' => $chassis_id,
                'health' => health_of($group)));
        }
        if (list.has($chassis, 'EnvironmentMetrics')) {
            $metrics = redfish_get($address, $chassis['EnvironmentMetrics']['@odata.id'], $user, $password);
            $reading = list.get(list.get($metrics, 'PowerWatts', array()), 'Reading', '');
            if ($reading != '') {
                $drawn['chassis ' . $chassis_id] = $reading;
            }
        }
    }
}

if (list.count($items) == 0 && list.count($drawn) == 0) {
    fail('misconfigured', 'The Redfish service serves no power supply and no power reading',
        'No chassis has a Power or a PowerSubsystem resource; a blade reads its power from its enclosure.');
}
$names = instance_names($items);
foreach ($items as $key => $item) {
    value('health', $item['health'], $names[$key]);
}
foreach ($drawn as $name => $watts) {
    value('consumption', $watts, $name);
}