зеркало из https://github.com/github/vitess-gh.git
126 строки
3.2 KiB
Go
126 строки
3.2 KiB
Go
/*
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* Copyright 2019 The Vitess Authors.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// client.go is a sample for using the Vitess Go SQL driver.
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//
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// Before running this, start up a local example cluster as described in the
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// README.md file.
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//
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// Then run:
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// vitess$ . dev.env
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// vitess$ cd examples/local
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// vitess/examples/local$ go run client.go -server=localhost:15991
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package main
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import (
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"flag"
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"fmt"
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"math/rand"
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"os"
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"time"
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"vitess.io/vitess/go/vt/vitessdriver"
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)
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var (
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server = flag.String("server", "", "vtgate server to connect to")
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)
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func main() {
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flag.Parse()
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rand.Seed(time.Now().UnixNano())
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// Connect to vtgate.
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db, err := vitessdriver.Open(*server, "@master")
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if err != nil {
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fmt.Printf("client error: %v\n", err)
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os.Exit(1)
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}
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defer db.Close()
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// Insert some messages on random pages.
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fmt.Println("Inserting into master...")
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for i := 0; i < 3; i++ {
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tx, err := db.Begin()
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if err != nil {
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fmt.Printf("begin failed: %v\n", err)
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os.Exit(1)
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}
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page := rand.Intn(100) + 1
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timeCreated := time.Now().UnixNano()
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if _, err := tx.Exec("INSERT INTO messages (page,time_created_ns,message) VALUES (?,?,?)",
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page, timeCreated, "V is for speed"); err != nil {
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fmt.Printf("exec failed: %v\n", err)
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os.Exit(1)
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}
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if err := tx.Commit(); err != nil {
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fmt.Printf("commit failed: %v\n", err)
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os.Exit(1)
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}
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}
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// Read it back from the master.
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fmt.Println("Reading from master...")
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rows, err := db.Query("SELECT page, time_created_ns, message FROM messages")
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if err != nil {
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fmt.Printf("query failed: %v\n", err)
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os.Exit(1)
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}
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for rows.Next() {
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var page, timeCreated uint64
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var msg string
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if err := rows.Scan(&page, &timeCreated, &msg); err != nil {
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fmt.Printf("scan failed: %v\n", err)
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os.Exit(1)
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}
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fmt.Printf("(%v, %v, %q)\n", page, timeCreated, msg)
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}
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if err := rows.Err(); err != nil {
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fmt.Printf("row iteration failed: %v\n", err)
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os.Exit(1)
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}
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// Read from a replica.
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// Note that this may be behind master due to replication lag.
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fmt.Println("Reading from replica...")
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dbr, err := vitessdriver.Open(*server, "@replica")
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if err != nil {
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fmt.Printf("client error: %v\n", err)
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os.Exit(1)
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}
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defer dbr.Close()
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rows, err = dbr.Query("SELECT page, time_created_ns, message FROM messages")
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if err != nil {
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fmt.Printf("query failed: %v\n", err)
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os.Exit(1)
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}
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for rows.Next() {
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var page, timeCreated uint64
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var msg string
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if err := rows.Scan(&page, &timeCreated, &msg); err != nil {
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fmt.Printf("scan failed: %v\n", err)
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os.Exit(1)
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}
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fmt.Printf("(%v, %v, %q)\n", page, timeCreated, msg)
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}
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if err := rows.Err(); err != nil {
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fmt.Printf("row iteration failed: %v\n", err)
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os.Exit(1)
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}
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}
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