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-rw-r--r--libgo/go/database/sql/example_cli_test.go88
1 files changed, 88 insertions, 0 deletions
diff --git a/libgo/go/database/sql/example_cli_test.go b/libgo/go/database/sql/example_cli_test.go
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+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+package sql_test
+
+import (
+ "context"
+ "database/sql"
+ "flag"
+ "log"
+ "os"
+ "os/signal"
+ "time"
+)
+
+var pool *sql.DB // Database connection pool.
+
+func Example_openDBCLI() {
+ id := flag.Int64("id", 0, "person ID to find")
+ dsn := flag.String("dsn", os.Getenv("DSN"), "connection data source name")
+ flag.Parse()
+
+ if len(*dsn) == 0 {
+ log.Fatal("missing dsn flag")
+ }
+ if *id == 0 {
+ log.Fatal("missing person ID")
+ }
+ var err error
+
+ // Opening a driver typically will not attempt to connect to the database.
+ pool, err = sql.Open("driver-name", *dsn)
+ if err != nil {
+ // This will not be a connection error, but a DSN parse error or
+ // another initialization error.
+ log.Fatal("unable to use data source name", err)
+ }
+ defer pool.Close()
+
+ pool.SetConnMaxLifetime(0)
+ pool.SetMaxIdleConns(3)
+ pool.SetMaxOpenConns(3)
+
+ ctx, stop := context.WithCancel(context.Background())
+ defer stop()
+
+ appSignal := make(chan os.Signal, 3)
+ signal.Notify(appSignal, os.Interrupt)
+
+ go func() {
+ select {
+ case <-appSignal:
+ stop()
+ }
+ }()
+
+ Ping(ctx)
+
+ Query(ctx, *id)
+}
+
+// Ping the database to verify DSN provided by the user is valid and the
+// server accessible. If the ping fails exit the program with an error.
+func Ping(ctx context.Context) {
+ ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
+ defer cancel()
+
+ if err := pool.PingContext(ctx); err != nil {
+ log.Fatalf("unable to connect to database: %v", err)
+ }
+}
+
+// Query the database for the information requested and prints the results.
+// If the query fails exit the program with an error.
+func Query(ctx context.Context, id int64) {
+ ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+ defer cancel()
+
+ var name string
+ err := pool.QueryRowContext(ctx, "select p.name from people as p where p.id = :id;", sql.Named("id", id)).Scan(&name)
+ if err != nil {
+ log.Fatal("unable to execute search query", err)
+ }
+ log.Println("name=", name)
+}