db_postgres: report network metrics with hostname label

This can help figure out when it's necessary to discuss with
network operators to request a connection limit bump.
This commit is contained in:
Simon Ser 2022-03-08 11:04:23 +01:00
parent dac003960c
commit 421d3f258a

View File

@ -177,6 +177,9 @@ func (db *PostgresDB) Close() error {
} }
func (db *PostgresDB) RegisterMetrics(r prometheus.Registerer) error { func (db *PostgresDB) RegisterMetrics(r prometheus.Registerer) error {
if err := r.Register(&postgresMetricsCollector{db}); err != nil {
return err
}
return r.Register(promcollectors.NewDBStatsCollector(db.db, "main")) return r.Register(promcollectors.NewDBStatsCollector(db.db, "main"))
} }
@ -558,3 +561,78 @@ func (db *PostgresDB) StoreReadReceipt(ctx context.Context, networkID int64, rec
} }
return err return err
} }
func (db *PostgresDB) listTopNetworkAddrs(ctx context.Context) (map[string]int, error) {
ctx, cancel := context.WithTimeout(ctx, postgresQueryTimeout)
defer cancel()
addrs := make(map[string]int)
rows, err := db.db.QueryContext(ctx, `
SELECT addr, COUNT(addr) AS n
FROM "Network"
GROUP BY addr
ORDER BY n DESC`)
if err != nil {
return nil, err
}
defer rows.Close()
for rows.Next() {
var (
addr string
n int
)
if err := rows.Scan(&addr, &n); err != nil {
return nil, err
}
addrs[addr] = n
}
return addrs, rows.Err()
}
var postgresNetworksTotalDesc = prometheus.NewDesc("soju_networks_total", "Number of networks", []string{"hostname"}, nil)
type postgresMetricsCollector struct {
db *PostgresDB
}
var _ prometheus.Collector = (*postgresMetricsCollector)(nil)
func (c *postgresMetricsCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- postgresNetworksTotalDesc
}
func (c *postgresMetricsCollector) Collect(ch chan<- prometheus.Metric) {
addrs, err := c.db.listTopNetworkAddrs(context.TODO())
if err != nil {
ch <- prometheus.NewInvalidMetric(postgresNetworksTotalDesc, err)
return
}
// Group by hostname
hostnames := make(map[string]int)
for addr, n := range addrs {
hostname := addr
network := Network{Addr: addr}
if u, err := network.URL(); err == nil {
hostname = u.Hostname()
}
hostnames[hostname] += n
}
// Group networks with low counts for privacy
watermark := 10
grouped := 0
for hostname, n := range hostnames {
if n >= watermark && hostname != "" && hostname != "*" {
ch <- prometheus.MustNewConstMetric(postgresNetworksTotalDesc, prometheus.GaugeValue, float64(n), hostname)
} else {
grouped += n
}
}
if grouped > 0 {
ch <- prometheus.MustNewConstMetric(postgresNetworksTotalDesc, prometheus.GaugeValue, float64(grouped), "*")
}
}