Add connection pooling settings

Author: matteocontrini

README.md

@@ -33,3 +33,5 @@ Configure Caddy to use the PostgreSQL storage module. Example `Caddyfile`:
 The `dsn` parameter is a [PostgreSQL connection string](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING), either as a key/value string or as a connection URI.
 
 The `sslmode` connection parameter defaults to `require`. We recommend setting a `statement_timeout` (e.g. `30s`) and other [basic parameters](https://brandur.org/fragments/postgres-parameters).
+
+This module implementation already sets the following connection pooling parameters: maximum open connection (`10`), maximum idle connections (`3`), and connection maximum idle time (`1h`).

storage.go

@@ -78,6 +78,13 @@ func (s *PostgresStorage) Provision(ctx caddy.Context) error {
 		return err
 	}
 
+	// Limit number of open connections
+	db.SetMaxOpenConns(10)
+	// Limit idle connections to 3
+	db.SetMaxIdleConns(3)
+	// Close idle connections after 1 hour
+	db.SetConnMaxIdleTime(time.Hour)
+
 	s.db = db
 
 	// Initialize pglock