Installation

phil/monitoring-bundle

Requirements

Package	Version	Why
PHP	8.5 or later
`symfony/config`, `symfony/dependency-injection`, `symfony/http-kernel`, `symfony/http-foundation`, `symfony/console`	`^8.2`	The configuration, the services, the endpoints, the maintenance listener and the commands.
`symfony/messenger`, `symfony/notifier`	`^8.2`	The queues, the watch message and the alerts of late tasks.
`symfony/lock`	`^8.2`	The lock that keeps two rounds of the dead-man switch from alerting the same lateness.
`symfony/filesystem`, `psr/cache`		The flag file and the cache stores.
`psr/clock`, `psr/log`, `psr/container`		The time of the checks and the beats, the logged failures, the receivers of the queues.
`symfony/routing`	`^8.2`	The routes of the endpoints and of the page of the queues.
`doctrine/dbal`	`^4.5`	The checks of DBAL connections; not needed without `health.database`.
`league/flysystem`	`^3.30`	The checks of storages; not needed without `health.flysystem`.
`symfony/scheduler`	`^8.2`	The beats of scheduled messages; cron jobs beat through the command without it.
`twig/twig`	`^3.21`	The maintenance page and the page of the queues; the maintenance answer is plain text without it.
`symfony/security-core`, `symfony/security-csrf`	`^8.2`	The roles of the maintenance mode, and the page of the queues and its actions.

Installing

composer require phil/monitoring-bundle

// config/bundles.php
return [
    // ...
    Phil\MonitoringBundle\PhilMonitoringBundle::class => ['all' => true],
];

The routes

The bundle declares no route of its own accord: import the endpoints of the monitors where they should answer, and the page of the queues behind the firewall that knows the role it asks for.

# config/routes/phil_monitoring.yaml
phil_monitoring_health:
    resource: '@PhilMonitoringBundle/config/routes/health.php'
    prefix: /_health

phil_monitoring_queues:
    resource: '@PhilMonitoringBundle/config/routes/queues.php'
    prefix: /admin/queues

The endpoints need no session and no user: put them outside any firewall that would redirect a monitor to a login page, or in a stateless one.

The stores

The heartbeats live in cache.app and the maintenance flag in var/maintenance.json. Both hold only when every worker and server shares them:

on one server, the defaults hold, provided cache.app is not an array or APCu pool;
on several servers, give the bundle a pool on a shared adapter that does not evict, and keep the maintenance in it.

# config/packages/cache.yaml
framework:
    cache:
        pools:
            cache.monitoring:
                adapter: cache.adapter.redis

# config/packages/phil_monitoring.yaml
phil_monitoring:
    cache_pool: cache.monitoring
    maintenance:
        store: cache

A pool that evicts loses beats — a task then reads as never run, which is not alerted — and ends a maintenance. On Valkey or Redis, give that pool a server or database without an eviction policy.