lectures: 07-sql rc1

go.mod

@@ -3,6 +3,9 @@ module gitlab.com/slon/shad-go
 go 1.13
 
 require (
+	github.com/ClickHouse/clickhouse-go v1.4.0 // indirect
+	github.com/DATA-DOG/go-sqlmock v1.4.1
+	github.com/go-redis/redis v6.15.7+incompatible // indirect
 	github.com/go-resty/resty/v2 v2.1.0
 	github.com/gofrs/uuid v3.2.0+incompatible
 	github.com/golang/mock v1.4.1

go.sum

@@ -1,10 +1,16 @@
 cloud.google.com/go v0.0.0-20170206221025-ce650573d812/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/ClickHouse/clickhouse-go v1.4.0 h1:cC1DEZ1TL74QviZY4svlwow84X5r7/BGd78kf18swhI=
+github.com/ClickHouse/clickhouse-go v1.4.0/go.mod h1:EaI/sW7Azgz9UATzd5ZdZHRUhHgv5+JMS9NSr2smCJI=
+github.com/DATA-DOG/go-sqlmock v1.4.1 h1:ThlnYciV1iM/V0OSF/dtkqWb6xo5qITT1TJBG1MRDJM=
+github.com/DATA-DOG/go-sqlmock v1.4.1/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20190129172621-c8b1d7a94ddf/go.mod h1:aJ4qN3TfrelA6NZ6AXsXRfmEVaYin3EDbSPJrKS8OXo=
 github.com/aclements/go-gg v0.0.0-20170118225347-6dbb4e4fefb0/go.mod h1:55qNq4vcpkIuHowELi5C8e+1yUHtoLoOUR9QU5j7Tes=
 github.com/aclements/go-moremath v0.0.0-20161014184102-0ff62e0875ff/go.mod h1:idZL3yvz4kzx1dsBOAC+oYv6L92P1oFEhUXUB1A/lwQ=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
+github.com/bkaradzic/go-lz4 v1.0.0/go.mod h1:0YdlkowM3VswSROI7qDxhRvJ3sLhlFrRRwjwegp5jy4=
+github.com/cloudflare/golz4 v0.0.0-20150217214814-ef862a3cdc58/go.mod h1:EOBUe0h4xcZ5GoxqC5SDxFQ8gwyZPKQoEzownBlhI80=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
 github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk=
@@ -17,6 +23,8 @@ github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/go-redis/redis v6.15.7+incompatible h1:3skhDh95XQMpnqeqNftPkQD9jL9e5e36z/1SUm6dy1U=
+github.com/go-redis/redis v6.15.7+incompatible/go.mod h1:NAIEuMOZ/fxfXJIrKDQDz8wamY7mA7PouImQ2Jvg6kA=
 github.com/go-resty/resty/v2 v2.1.0 h1:Z6IefCpUMfnvItVJaJXWv/pMiiD11So35QgwEELsldE=
 github.com/go-resty/resty/v2 v2.1.0/go.mod h1:dZGr0i9PLlaaTD4H/hoZIDjQ+r6xq8mgbRzHZf7f2J8=
 github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
@@ -113,6 +121,7 @@ github.com/mattn/go-sqlite3 v1.9.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOq
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
+github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

lectures/07-sql/clickhouse/clickhouse.go

@@ -0,0 +1,29 @@
+package clickhouse
+
+import (
+	"context"
+	"database/sql"
+
+	_ "github.com/ClickHouse/clickhouse-go"
+)
+
+func Example(ctx context.Context) {
+	db, _ := sql.Open("clickhouse", "tcp://127.0.0.1:9000?debug=true")
+	defer db.Close()
+
+	// Начало батча
+	tx, _ := db.BeginTx(ctx, nil)
+	defer tx.Rollback()
+
+	// Описание батча
+	stmt, _ := tx.PrepareContext(ctx, "INSERT INTO example (id) VALUES (?)")
+	defer stmt.Close()
+
+	// Добавление данных
+	for i := 0; i < 100; i++ {
+		_, _ = stmt.ExecContext(ctx, i)
+	}
+
+	// Отправка батча в ClickHouse
+	_ = tx.Commit()
+}

lectures/07-sql/query/query.go

@@ -7,7 +7,7 @@ import (
 )
 
 func Query(ctx context.Context, db *sql.DB) {
-	rows, err := db.QueryContext(ctx, "SELECT id, name FROM users WHERE id = $1", 1)
+	rows, err := db.QueryContext(ctx, "SELECT id, name FROM users")
 	if err != nil {
 		log.Fatal(err)
 	}

lectures/07-sql/redis/redis.go

@@ -0,0 +1,31 @@
+package redis
+
+import (
+	"log"
+	"time"
+
+	"github.com/go-redis/redis"
+)
+
+func Example() {
+	rdb := redis.NewUniversalClient(&redis.UniversalOptions{
+		MasterName: "master",
+		Addrs:      []string{":26379"},
+	})
+	defer rdb.Close()
+
+	if err := rdb.Ping(); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := rdb.Set("key", "value", time.Hour).Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	value, err := rdb.Get("key").Result()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	log.Println(value)
+}

lectures/07-sql/resources/conn.go

@@ -0,0 +1,16 @@
+package resources
+
+import (
+	"context"
+	"database/sql"
+	"log"
+)
+
+func ConnExhaust(ctx context.Context, db *sql.DB) {
+	c, err := db.Conn(ctx)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	_ = c.PingContext(ctx)
+}

lectures/07-sql/resources/queries.go

@@ -0,0 +1,72 @@
+package resources
+
+import (
+	"context"
+	"database/sql"
+	"log"
+)
+
+func QueryDeadlock(ctx context.Context, db *sql.DB) {
+	rows, _ := db.QueryContext(ctx, "SELECT id, name FROM users")
+	defer rows.Close()
+
+	for rows.Next() {
+		var id int
+		var name string
+		_ = rows.Scan(&id, &name)
+
+		rowsAddrs, _ := db.QueryContext(
+			ctx,
+			"SELECT address FROM addresses WHERE user_id = $1",
+			id,
+		)
+		defer rowsAddrs.Close()
+
+		var addr string
+		_ = rowsAddrs.Scan(&addr)
+
+		log.Println(id, name, addr)
+	}
+}
+
+func QueryDeadlockFixOne(ctx context.Context, db *sql.DB) {
+	type Res struct {
+		ID   int
+		Name string
+		Addr string
+	}
+	var values []Res
+	rows, _ := db.QueryContext(ctx, "SELECT id, name FROM users")
+
+	for rows.Next() {
+		var res Res
+		_ = rows.Scan(&res.ID, &res.Name)
+		values = append(values, res)
+	}
+	rows.Close()
+
+	for _, v := range values {
+		_ = db.QueryRowContext(
+			ctx,
+			"SELECT address FROM addresses WHERE user_id = $1",
+			v.ID,
+		).Scan(&v.Addr)
+		log.Println(v)
+	}
+}
+
+func QueryDeadlockFixTwo(ctx context.Context, db *sql.DB) {
+	rows, _ := db.QueryContext(
+		ctx,
+		"SELECT u.id, u.name, a.address FROM users AS u, addresses as a WHERE u.id == a.user_id",
+	)
+	defer rows.Close()
+
+	for rows.Next() {
+		var id int
+		var name string
+		var addr string
+		_ = rows.Scan(&id, &name, &addr)
+		log.Println(id, name, addr)
+	}
+}

lectures/07-sql/resources/rows.go

@@ -0,0 +1,24 @@
+package resources
+
+import (
+	"context"
+	"database/sql"
+	"log"
+)
+
+func RowsExhaust(ctx context.Context, db *sql.DB) {
+	rows, err := db.QueryContext(ctx, "SELECT id, name FROM users")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if rows.Next() {
+		var id int
+		var name string
+		if err := rows.Scan(&id, &name); err != nil {
+			log.Fatal(err)
+		}
+
+		log.Println(id, name)
+	}
+}

lectures/07-sql/resources/tx.go

@@ -0,0 +1,35 @@
+package resources
+
+import (
+	"context"
+	"database/sql"
+	"log"
+)
+
+func TxExhaust(ctx context.Context, db *sql.DB) {
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	if _, err = tx.ExecContext(ctx, `UPDATE users SET name = "Surl/Tesh-echer" WHERE id = 1`); err != nil {
+		log.Println(err)
+		return
+	}
+
+	if err = tx.Commit(); err != nil {
+		log.Println(err)
+	}
+}
+
+func TxDeadlock(ctx context.Context, db *sql.DB) {
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	_, _ = db.QueryContext(ctx, "SELECT id, name FROM users")
+	_, _ = db.QueryContext(ctx, "SELECT id, name FROM users")
+}

lectures/07-sql/sql.slide

@@ -101,19 +101,33 @@ database/sql
 
 * Типовые ошибки и подводные камни
 
-* Deadlock
+* Запросы - deadlock
 
-- ПРИМЕР много SQL вызовов подряд без вычитки данных
+.code resources/queries.go /^func QueryDeadlock/,/^}/
 
-* Исчерпание ресурсов
+* Запросы - deadlock - fix 1
 
-- ПРИМЕР незакрытие транзакций
+.code resources/queries.go /^func QueryDeadlockFixOne/,/^}/
-- ПРИМЕР незакрытие rows
-- ПРИМЕР неотдача коннектов
 
-* Рефлексия
+* Запросы - deadlock - fix 2
 
-ПРИМЕР ColumnType
+.code resources/queries.go /^func QueryDeadlockFixTwo/,/^}/
+
+* Запросы - исчерпание ресурсов
+
+.code resources/rows.go /^func RowsExhaust/,/^}/
+
+* Транзакции - исчерпание ресурсов
+
+.code resources/tx.go /^func TxExhaust/,/^}/
+
+* Транзакции - deadlock
+
+.code resources/tx.go /^func TxDeadlock/,/^}/
+
+* Коннекты - исчерпание ресурсов
+
+.code resources/conn.go /^func ConnExhaust/,/^}/
 
 * Удобства и расширения
 
@@ -160,22 +174,24 @@ database/sql
 
 .code sqlx/named.go /^func Insert/,/^}/
 
-* GORM
-
-- ORM которая умеет всё
-- ORM которая не умеет ничего
-
-* Моки
-
-Здесь будет пара слайдов о github.com/DATA-DOG/go-sqlmock
-
 * Нетипичные драйверы
 
-- драйвер к кликхаусу использует транзакции как батчинг (ЗДЕСЬ БУДЕТ ПРИМЕР)
+* Нетипичные драйверы - github.com/DATA-DOG/go-sqlmock
 
-* Пример не-sql драйвера
+.play sqlmock/sqlmock_test.go /^func TestSelect/,/^}/
 
-ПРИМЕР go-redis
+* Нетипичные драйверы - github.com/ClickHouse/clickhouse-go
+
+.code clickhouse/clickhouse.go /^func Example/,/^}/
+
+* Не-SQL драйверы - Redis
+
+.code redis/redis.go /^func Example/,/^}/
+
+* ORM
+
+- github.com/jinzhu/gorm
+- github.com/go-pg/pg
 
 * Популярные базы данных и их драйверы
 

lectures/07-sql/sqlmock/sqlmock_test.go

@@ -0,0 +1,35 @@
+package sqlmock
+
+import (
+	"database/sql"
+	"log"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSelect(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	mock.ExpectBegin()
+	mock.ExpectExec("SELECT name FROM users WHERE id = ?").
+		WithArgs(1).
+		WillReturnError(sql.ErrNoRows)
+	mock.ExpectCommit()
+
+	tx, err := db.Begin()
+	require.NoError(t, err)
+
+	_, err = db.Exec("SELECT name FROM users WHERE id = ?", 1)
+	require.NotNil(t, err)
+	require.Equal(t, err, sql.ErrNoRows)
+
+	require.NoError(t, tx.Commit())
+
+	require.NoError(t, mock.ExpectationsWereMet())
+}