Add sqldb and set packages

2018-06-23 23:46:35 +02:00
parent 0df8b1ec84
commit b06910f223
31 changed files with 2983 additions and 0 deletions
@@ -0,0 +1,106 @@
+package sqldb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/juju/errors"
+)
+
+// Conn represents database connection.
+type Conn struct {
+	db *sql.DB
+
+	beforeCallbacks []BeforeCallback
+	afterCallbacks  []AfterCallback
+}
+
+type (
+	// BeforeCallback is a kind of function that can be called before a query is
+	// executed.
+	BeforeCallback func(ctx context.Context, query string)
+	// AfterCallback is a kind of function that can be called after a query was
+	// executed.
+	AfterCallback func(ctx context.Context, query string, took time.Duration, err error)
+)
+
+// Flavor defines a kind of SQL database.
+type Flavor string
+
+const (
+	// MySQL is the MySQL SQL flavor.
+	MySQL Flavor = "mysql"
+	// PostgreSQL is the PostgreSQL SQL flavor.
+	PostgreSQL Flavor = "postgresql"
+)
+
+// Connect establishes a new database connection.
+func Connect(ctx context.Context, f Flavor, dsn string) (*Conn, error) {
+	conn, err := sql.Open(string(f), dsn)
+	if err != nil {
+		return nil, errors.Annotate(err, "Failed to establish connection")
+	}
+	err = conn.PingContext(ctx)
+	if err != nil {
+		return nil, errors.Annotate(err, "Connection is not responding")
+	}
+	return &Conn{db: conn}, nil
+}
+
+// Exec executes a query and does not expect any result.
+func (c *Conn) Exec(ctx context.Context, query string, args ...interface{}) Result {
+	c.callBefore(ctx, query)
+	startedAt := time.Now()
+	res, err := c.db.ExecContext(ctx, query, args...)
+	c.callAfter(ctx, query, time.Since(startedAt), err)
+	if err != nil {
+		return result{err: err}
+	}
+	return result{res: res}
+}
+
+// Query executes a query and returns a result object that can later be used to
+// retrieve values.
+func (c *Conn) Query(ctx context.Context, query string, args ...interface{}) Result {
+	var r result
+	c.callBefore(ctx, query)
+	startedAt := time.Now()
+	r.rows, r.err = c.db.QueryContext(ctx, query, args...)
+	c.callAfter(ctx, query, time.Since(startedAt), r.err)
+	return r
+}
+
+// DB returns the underlying DB object.
+func (c *Conn) DB() *sql.DB {
+	return c.db
+}
+
+// Close closes the connection.
+func (c *Conn) Close() error {
+	return c.db.Close()
+}
+
+// Before adds a callback function that would be called before a query is
+// executed.
+func (c *Conn) Before(cb BeforeCallback) {
+	c.beforeCallbacks = append(c.beforeCallbacks, cb)
+}
+
+// After adds a callback function that would be called after a query was
+// executed.
+func (c *Conn) After(cb AfterCallback) {
+	c.afterCallbacks = append(c.afterCallbacks, cb)
+}
+
+func (c *Conn) callBefore(ctx context.Context, query string) {
+	for _, cb := range c.beforeCallbacks {
+		cb(ctx, query)
+	}
+}
+
+func (c *Conn) callAfter(ctx context.Context, query string, took time.Duration, err error) {
+	for _, cb := range c.afterCallbacks {
+		cb(ctx, query, took, err)
+	}
+}
@@ -0,0 +1,312 @@
+package sqldb
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+)
+
+// Result represents query result.
+type Result interface {
+	// Load decodes rows into provided variable.
+	Load(dest interface{}) Result
+	// Error returns an error if one happened during query execution.
+	Error() error
+	// Rows returns original database rows object.
+	Rows() *sql.Rows
+	// LastInsertID returns the last inserted record ID for results obtained
+	// from Exec calls.
+	LastInsertID() int64
+	// RowsAffected returns the number of rows affected for results obtained
+	// from Exec calls.
+	RowsAffected() int64
+}
+
+type result struct {
+	rows *sql.Rows
+	res  sql.Result
+	err  error
+}
+
+func (r result) Rows() *sql.Rows {
+	return r.rows
+}
+
+func (r result) Error() error {
+	return r.err
+}
+
+func (r result) LastInsertID() int64 {
+	if r.res == nil {
+		return 0
+	}
+	id, err := r.res.LastInsertId()
+	if err != nil {
+		return 0
+	}
+	return id
+}
+
+func (r result) RowsAffected() int64 {
+	if r.res == nil {
+		return 0
+	}
+	ra, err := r.res.RowsAffected()
+	if err != nil {
+		return 0
+	}
+	return ra
+}
+
+func (r result) Load(dest interface{}) Result {
+	if r.err != nil {
+		return r
+	}
+	defer r.rows.Close()
+
+	dtyp := reflect.TypeOf(dest)
+	if dtyp.Kind() != reflect.Ptr {
+		panic("Value must be a pointer")
+	}
+	dtyp = dtyp.Elem()
+
+	switch dtyp.Kind() {
+	case reflect.Struct:
+		r.loadStruct(dtyp, dest)
+	case reflect.Map:
+		r.loadMap(dest.(*map[string]interface{}))
+	case reflect.Slice:
+		switch dtyp.Elem().Kind() {
+		case reflect.Struct:
+			r.loadSliceOfStructs(dtyp, dest)
+		case reflect.Map:
+			r.loadSliceOfMaps(dest.(*[]map[string]interface{}))
+		default:
+			r.loadSlice(dtyp, dest)
+		}
+	default:
+		r.loadValue(dest)
+	}
+
+	if r.err == nil && r.rows.Err() != nil {
+		return r.withError(r.rows.Err())
+	}
+
+	return r
+}
+
+func (r *result) loadValue(dest interface{}) {
+	if r.rows.Next() {
+		r.err = r.rows.Scan(dest)
+	}
+}
+
+func (r *result) loadSlice(typ reflect.Type, dest interface{}) {
+	vSlice := reflect.MakeSlice(typ, 0, 0)
+	for r.rows.Next() {
+		val := reflect.New(typ.Elem())
+		r.err = r.rows.Scan(val.Interface())
+		if r.err != nil {
+			return
+		}
+		vSlice = reflect.Append(vSlice, val.Elem())
+	}
+	reflect.ValueOf(dest).Elem().Set(vSlice)
+}
+
+func (r *result) loadMap(dest *map[string]interface{}) {
+	if !r.rows.Next() {
+		return
+	}
+
+	cols, err := r.rows.Columns()
+	if err != nil {
+		r.err = err
+		return
+	}
+	colTypes, err := r.rows.ColumnTypes()
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	vals := make([]interface{}, len(cols))
+	for i := range cols {
+		vals[i] = newValue(colTypes[i])
+	}
+	err = r.rows.Scan(vals...)
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	if *dest == nil {
+		*dest = make(map[string]interface{}, len(cols))
+	}
+	for i, col := range cols {
+		switch tval := vals[i].(type) {
+		case *int64:
+			(*dest)[col] = *tval
+		case *string:
+			(*dest)[col] = *tval
+		case *bool:
+			(*dest)[col] = *tval
+		}
+	}
+}
+
+func (r *result) loadSliceOfMaps(dest *[]map[string]interface{}) {
+	cols, err := r.rows.Columns()
+	if err != nil {
+		r.err = err
+		return
+	}
+	colTypes, err := r.rows.ColumnTypes()
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	if *dest == nil {
+		*dest = make([]map[string]interface{}, 0)
+	}
+	for r.rows.Next() {
+		vals := make([]interface{}, len(cols))
+		for i := range cols {
+			vals[i] = newValue(colTypes[i])
+		}
+		err = r.rows.Scan(vals...)
+		if err != nil {
+			r.err = err
+			return
+		}
+
+		row := make(map[string]interface{}, len(cols))
+		for i, col := range cols {
+			switch tval := vals[i].(type) {
+			case *int64:
+				row[col] = *tval
+			case *string:
+				row[col] = *tval
+			case *bool:
+				row[col] = *tval
+			}
+		}
+		*dest = append(*dest, row)
+	}
+}
+
+func (r *result) loadStruct(typ reflect.Type, dest interface{}) {
+	if !r.rows.Next() {
+		return
+	}
+
+	cols, err := r.rows.Columns()
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	val := reflect.ValueOf(dest).Elem()
+	vals := make([]interface{}, len(cols))
+	tm := tagMap(cols, val.Type())
+	for i := range cols {
+		if fi, ok := tm[i]; ok {
+			fval := val.Field(fi)
+			vals[i] = reflect.New(fval.Type()).Interface()
+		} else {
+			var dummy interface{}
+			vals[i] = &dummy
+		}
+	}
+
+	err = r.rows.Scan(vals...)
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	for i, fi := range tm {
+		fval := val.Field(fi)
+		fval.Set(reflect.ValueOf(vals[i]).Elem())
+	}
+}
+
+func (r *result) loadSliceOfStructs(typ reflect.Type, dest interface{}) {
+	cols, err := r.rows.Columns()
+	if err != nil {
+		r.err = err
+		return
+	}
+
+	vSlice := reflect.ValueOf(dest).Elem()
+	tSlice := vSlice.Type()
+	tElem := tSlice.Elem()
+	tm := tagMap(cols, tElem)
+
+	for r.rows.Next() {
+		vals := make([]interface{}, len(cols))
+		val := reflect.New(tElem).Elem()
+		for i := range cols {
+			if fi, ok := tm[i]; ok {
+				fval := val.Field(fi)
+				vals[i] = reflect.New(fval.Type()).Interface()
+			} else {
+				var dummy interface{}
+				vals[i] = &dummy
+			}
+		}
+
+		err = r.rows.Scan(vals...)
+		if err != nil {
+			r.err = err
+			return
+		}
+
+		for i, fi := range tm {
+			fval := val.Field(fi)
+			fval.Set(reflect.ValueOf(vals[i]).Elem())
+		}
+		vSlice.Set(reflect.Append(vSlice, val))
+	}
+}
+
+func (r result) withError(err error) Result {
+	r.err = err
+	return r
+}
+
+func newValue(typ *sql.ColumnType) interface{} {
+	switch typ.DatabaseTypeName() {
+	case "VARCHAR", "NVARCHAR", "TEXT":
+		var s string
+		return &s
+	case "INT", "BIGINT":
+		var i int64
+		return &i
+	case "BOOL":
+		var b bool
+		return &b
+	default:
+		panic(fmt.Errorf("Unsupported MySQL type: %s", typ.DatabaseTypeName()))
+	}
+}
+
+func tagMap(cols []string, typ reflect.Type) map[int]int {
+	fieldIndices := map[string]int{}
+	for i := 0; i < typ.NumField(); i++ {
+		tag := typ.Field(i).Tag.Get("db")
+		if tag != "" {
+			fieldIndices[tag] = i
+		}
+	}
+
+	colFields := map[int]int{}
+	for i, col := range cols {
+		if fi, ok := fieldIndices[col]; ok {
+			colFields[i] = fi
+		}
+	}
+
+	return colFields
+}
@@ -0,0 +1,74 @@
+package sqldb
+
+import (
+	"context"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestLoadSingleValue(t *testing.T) {
+	ctx := context.Background()
+	exp := int(1)
+	var out int
+	mustT(t, conn.Query(ctx, "SELECT 1").Load(&out))
+	if exp != out {
+		t.Errorf("Value doesn't match: expected %d, got %d", exp, out)
+	}
+}
+
+func TestLoadSlice(t *testing.T) {
+	ctx := context.Background()
+	exp := []int{1, 2}
+	var out []int
+	mustT(t, conn.Query(ctx, "SELECT id FROM sqldb_test").Load(&out))
+	if !cmp.Equal(exp, out) {
+		t.Errorf("Values dont't match: %s", cmp.Diff(exp, out))
+	}
+}
+
+func TestLoadMap(t *testing.T) {
+	ctx := context.Background()
+	exp := map[string]interface{}{"id": int64(1), "name": "Alice"}
+	var out map[string]interface{}
+	mustT(t, conn.Query(ctx, "SELECT * FROM sqldb_test WHERE id = 1").Load(&out))
+	if !cmp.Equal(exp, out) {
+		t.Errorf("Record doesn't match: %s", cmp.Diff(exp, out))
+	}
+}
+
+func TestLoadSliceOfMaps(t *testing.T) {
+	ctx := context.Background()
+	exp := []map[string]interface{}{
+		{"id": int64(1), "name": "Alice"},
+		{"id": int64(2), "name": "Bob"},
+	}
+	var out []map[string]interface{}
+	mustT(t, conn.Query(ctx, "SELECT * FROM sqldb_test ORDER BY id ASC").Load(&out))
+	if !cmp.Equal(exp, out) {
+		t.Errorf("Records don't match: %s", cmp.Diff(exp, out))
+	}
+}
+
+func TestLoadStruct(t *testing.T) {
+	ctx := context.Background()
+	exp := record{ID: 1, Name: "Alice"}
+	var out record
+	mustT(t, conn.Query(ctx, "SELECT * FROM sqldb_test WHERE id = 1").Load(&out))
+	if !cmp.Equal(exp, out) {
+		t.Errorf("Record doesn't match: %s", cmp.Diff(exp, out))
+	}
+}
+
+func TestLoadSliceOfStructs(t *testing.T) {
+	ctx := context.Background()
+	exp := []record{
+		{ID: 1, Name: "Alice"},
+		{ID: 2, Name: "Bob"},
+	}
+	var out []record
+	mustT(t, conn.Query(ctx, "SELECT * FROM sqldb_test").Load(&out))
+	if !cmp.Equal(exp, out) {
+		t.Errorf("Records don't match: %s", cmp.Diff(exp, out))
+	}
+}
@@ -0,0 +1,77 @@
+package sqldb
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"testing"
+
+	_ "github.com/go-sql-driver/mysql" // MySQL driver
+)
+
+type record struct {
+	ID   uint   `db:"id"`
+	Name string `db:"name"`
+}
+
+var conn *Conn
+
+func TestMain(m *testing.M) {
+	dsn := flag.String("dsn", "", "Database source name")
+	flag.Parse()
+	if *dsn == "" {
+		log.Println("Database source name is not provided, skipping package tests")
+		os.Exit(0)
+	}
+
+	log.Println("Establishing connection to the test database")
+	ctx := context.Background()
+	var err error
+	conn, err = Connect(ctx, MySQL, *dsn)
+	if err != nil {
+		log.Fatalf("Failed to connect: %v\n", err)
+	}
+
+	log.Println("Seeding database")
+	must(conn.Exec(ctx, `
+		DROP TABLE IF EXISTS sqldb_test
+	`))
+	must(conn.Exec(ctx, `
+		CREATE TABLE sqldb_test (
+			id int(11) UNSIGNED NOT NULL,
+			name VARCHAR(10) DEFAULT '',
+			PRIMARY KEY (id)
+		) ENGINE=InnoDB DEFAULT CHARSET=ascii
+	`))
+	must(conn.Exec(ctx, `
+		INSERT INTO sqldb_test (id, name) 
+		VALUES
+			(1, "Alice"),
+			(2, "Bob")
+	`))
+
+	fmt.Println("Starting test suite")
+	exitCode := m.Run()
+	log.Println("Test suite finished")
+	if err := conn.Close(); err != nil {
+		log.Printf("Failed to close connection: %v\n", err)
+	}
+	os.Exit(exitCode)
+}
+
+func mustT(t *testing.T, r Result) Result {
+	t.Helper()
+	if r.Error() != nil {
+		t.Fatalf("Query failed: %v", r.Error())
+	}
+	return r
+}
+
+func must(r Result) Result {
+	if r.Error() != nil {
+		log.Fatalf("Query failed: %v\n", r.Error())
+	}
+	return r
+}