/
mysqlcsvdump.go
189 lines (163 loc) · 4.16 KB
/
mysqlcsvdump.go
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package main
import (
"compress/gzip"
"database/sql"
"flag"
"fmt"
csv "github.com/JensRantil/go-csv"
"github.com/JensRantil/go-csv/dialect"
_ "github.com/go-sql-driver/mysql"
"io"
"os"
)
// Queryable interface that matches sql.DB and sql.Tx.
type queryable interface {
Query(query string, args ...interface{}) (*sql.Rows, error)
}
func dump(tables []string, db queryable, outputDir string, compressOut, skipHeader bool, csvDialect *csv.Dialect) error {
for _, table := range tables {
err := dumpTable(table, db, outputDir, compressOut, skipHeader, csvDialect)
if err != nil {
fmt.Printf("Error dumping %s: %s\n", table, err)
}
}
return nil
}
func dumpTable(table string, db queryable, outputDir string, compressOut, skipHeader bool, csvDialect *csv.Dialect) error {
fname := outputDir + "/" + table + ".csv"
if compressOut {
fname = fname + ".gz"
}
f, err := os.Create(fname)
if err != nil {
return err
}
defer f.Close()
var out io.Writer
if compressOut {
gzout := gzip.NewWriter(f)
defer gzout.Close()
out = gzout
} else {
out = f
}
w := csv.NewDialectWriter(out, *csvDialect)
rows, err := db.Query("SELECT * FROM " + table) // Couldn't get placeholder expansion to work here
if err != nil {
return err
}
columns, err := rows.Columns()
if err != nil {
panic(err.Error())
}
if !skipHeader {
err = w.Write(columns) // Header
if err != nil {
return err
}
}
for rows.Next() {
// Shamelessly ripped (and modified) from http://play.golang.org/p/jxza3pbqq9
// Create interface set
values := make([]interface{}, len(columns))
scanArgs := make([]interface{}, len(values))
for i := range values {
scanArgs[i] = &values[i]
}
// Scan for arbitrary values
err = rows.Scan(scanArgs...)
if err != nil {
return err
}
// Print data
csvData := make([]string, 0, len(values))
for _, value := range values {
switch value.(type) {
default:
s := fmt.Sprintf("%s", value)
csvData = append(csvData, string(s))
}
}
err = w.Write(csvData)
if err != nil {
return err
}
}
w.Flush()
err = w.Error()
if err != nil {
return err
}
return nil
}
func getTables(db queryable) ([]string, error) {
tables := make([]string, 0, 10)
rows, err := db.Query("SHOW TABLES")
if err != nil {
return nil, err
}
for rows.Next() {
var table string
rows.Scan(&table)
tables = append(tables, table)
}
return tables, nil
}
func main() {
dialectBuilder := dialect.FromCommandLine()
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [options] [table#1 table#2 ... table#N]\n\n", os.Args[0])
fmt.Fprintln(os.Stderr, "If no tables are specified, all tables are dumped.\n")
fmt.Fprintln(os.Stderr, "Options:")
flag.PrintDefaults()
}
dbUser := flag.String("user", "root", "database user")
dbPassword := flag.String("password", "", "database password")
dbHost := flag.String("hostname", "", "database host")
dbPort := flag.Int("port", 3306, "database port")
outputDir := flag.String("outdir", "", "where output will be stored")
compressFiles := flag.Bool("compress-file", false, "whether compress connection or not")
useTransaction := flag.Bool("single-transaction", true, "whether to wrap everything in a transaction or not.")
skipHeader := flag.Bool("skip-header", false, "whether column header should be included or not")
flag.Parse()
csvDialect, err := dialectBuilder.Dialect()
if err != nil {
fmt.Println(err.Error())
flag.PrintDefaults()
os.Exit(1)
}
args := flag.Args()
if len(args) < 1 {
fmt.Println("Database name must be defined.")
flag.PrintDefaults()
os.Exit(1)
}
dbName := args[0]
dbUrl := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s", *dbUser, *dbPassword, *dbHost, *dbPort, dbName)
db, err := sql.Open("mysql", dbUrl)
if err != nil {
fmt.Fprintf(os.Stderr, "Could not connect to server: %s\n", err)
}
defer db.Close()
var q queryable
if *useTransaction {
tx, err := db.Begin()
if err != nil {
panic(err)
}
defer tx.Rollback()
q = tx
} else {
q = db
}
var tables []string
if len(args) > 1 {
tables = args[1:]
} else {
tables, err = getTables(q)
}
err = dump(tables, q, *outputDir, *compressFiles, *skipHeader, csvDialect)
if err != nil {
panic(err)
}
}