metric

var (
	PublishResults = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "blockqueue", Name: "persistence_total", Help: "Persistence outcomes.",
	}, []string{"result"})
	PendingMessages = prometheus.NewGauge(prometheus.GaugeOpts{
		Namespace: "blockqueue", Name: "pending_messages", Help: "Admitted messages waiting for commit.",
	})
	PendingBytes = prometheus.NewGauge(prometheus.GaugeOpts{
		Namespace: "blockqueue", Name: "pending_bytes", Help: "Admitted bytes waiting for commit.",
	})
	WriterHealthy = prometheus.NewGauge(prometheus.GaugeOpts{
		Namespace: "blockqueue", Name: "writer_healthy", Help: "Whether the last writer flush succeeded.",
	})
	PersistenceLag = prometheus.NewGauge(prometheus.GaugeOpts{
		Namespace: "blockqueue", Name: "persistence_lag_seconds", Help: "Age of the oldest message in the current flush.",
	})
	FlushTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "blockqueue", Name: "flush_total", Help: "Writer flush outcomes.",
	}, []string{"result"})
	FlushSize = prometheus.NewHistogram(prometheus.HistogramOpts{
		Namespace: "blockqueue", Name: "flush_size", Help: "Messages per database flush.", Buckets: prometheus.ExponentialBuckets(1, 2, 11),
	})
	FlushDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
		Namespace: "blockqueue", Name: "flush_duration_seconds", Help: "Database flush duration.",
	})
	DeliveryOperations = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "blockqueue", Name: "delivery_operation_total", Help: "Delivery ACK/NACK/lease outcomes.",
	}, []string{"operation", "result"})
	DeliveryDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Namespace: "blockqueue", Name: "delivery_operation_duration_seconds", Help: "Delivery operation latency.",
	}, []string{"operation"})
	CheckpointDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
		Namespace: "blockqueue", Name: "checkpoint_duration_seconds", Help: "SQLite checkpoint duration.",
	})
	CheckpointResults = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "blockqueue", Name: "checkpoint_total", Help: "SQLite checkpoint outcomes.",
	}, []string{"result"})
	SchedulerOperations = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "blockqueue", Name: "scheduler_operation_total", Help: "Scheduler outcomes.",
	}, []string{"operation", "result"})
)