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Diffstat (limited to 'libgo/go/database/sql/example_cli_test.go')
-rw-r--r-- | libgo/go/database/sql/example_cli_test.go | 88 |
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 new file mode 100644 index 00000000000..c87c508a141 --- /dev/null +++ b/libgo/go/database/sql/example_cli_test.go @@ -0,0 +1,88 @@ +// 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) +} |