implement collect

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

README.md

@@ -1 +1,52 @@
-# micro-wrapper-sql
+# micro-wrapper-sqlpackage postgres
+
+Example for For postgres 
+
+```go
+import (
+	"fmt"
+	"net/url"
+	"time"
+
+	"github.com/jackc/pgx/v4"
+	"github.com/jackc/pgx/v4/stdlib"
+	"github.com/jmoiron/sqlx"
+)
+
+func Connect(cfg *PostgresConfig) (*sqlx.DB, error) {
+	// format connection string
+	dbstr := fmt.Sprintf(
+		"postgres://%s:%s@%s/%s?sslmode=disable&statement_cache_mode=describe",
+		cfg.Login,
+		url.QueryEscape(cfg.Passw),
+		cfg.Addr,
+		cfg.DBName,
+	)
+
+	// parse connection string
+	dbConf, err := pgx.ParseConfig(dbstr)
+	if err != nil {
+		return nil, err
+	}
+
+	// needed for pgbouncer
+	dbConf.RuntimeParams = map[string]string{
+		"standard_conforming_strings": "on",
+		"application_name":            cfg.AppName,
+	}
+	// may be needed for pbbouncer, needs to check
+	//dbConf.PreferSimpleProtocol = true
+	// register pgx conn
+	connStr := stdlib.RegisterConnConfig(dbConf)
+
+	db, err := sqlx.Connect("pgx", connStr)
+	if err != nil {
+		return nil, err
+	}
+	db.SetMaxOpenConns(int(cfg.ConnMax))
+	db.SetMaxIdleConns(int(cfg.ConnMax / 2))
+	db.SetConnMaxLifetime(time.Duration(cfg.ConnLifetime) * time.Second)
+	db.SetConnMaxIdleTime(time.Duration(cfg.ConnMaxIdleTime) * time.Second)
+	return db, nil
+}
+```