connection pooling for Ci/CD to wait for oracle to startup...

dialects/oci8/contrib/connection.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"database/sql"
+	"flag"
+	"fmt"
+	"os"
+	"time"
+
+	_ "github.com/mattn/go-oci8"
+)
+
+const maxAttemtps = 60
+const wait = 10
+
+func main() {
+	var host string
+	flag.StringVar(&host, "h", "oracle", "hostname for oracle connection")
+	flag.Parse()
+	dbDSN := os.Getenv("GORM_DSN")
+	if dbDSN == "" {
+		dbDSN = fmt.Sprintf("gorm/gorm@%s:1521/XEPDB1", host)
+	}
+	fmt.Println("connecting to: ", dbDSN)
+	for i := 0; i < maxAttemtps; i++ {
+		db, err := sql.Open("oci8", dbDSN)
+		if err != nil {
+			fmt.Println(err.Error())
+			fmt.Println("sleeping: ", wait, " seconds...")
+			time.Sleep(wait * time.Second)
+			continue
+		}
+		q := "select sysdate from dual"
+		rows, err := db.Query(q)
+		if err != nil {
+			fmt.Println(err.Error())
+			fmt.Println("sleeping: ", wait, " seconds...")
+			time.Sleep(wait * time.Second)
+			continue
+		}
+		defer rows.Close()
+		var thedate string
+		for rows.Next() {
+			err := rows.Scan(&thedate)
+			if err != nil {
+				fmt.Println(err.Error())
+				fmt.Println("sleeping: ", wait, " seconds...")
+				time.Sleep(wait * time.Second)
+				continue
+			}
+		}
+		fmt.Println("connected to oracle...")
+		return
+	}
+	fmt.Println("unable to connect.")
+	os.Exit(-1)
+}