Prep

Prep finds all SQL statements in a Go package and instruments db connection with prepared statements. It allows you to benefit from the prepared SQL statements almost without any changes to your code.

Prep consists of two parts:

• A command line tool that finds all SQL statements in your code
• A package that instruments your code with prepared SQL statements using the found ones

Usage

Generate a list of SQL statements used in your application

$ cat example.go

funcmain() {
db, err:=sql.Open("mysql", "user:pass@tcp(localhost:3306)/mysql")
iferr!=nil {
panic(err)
}
constquery=`SELECT CONCAT("Hello ", ?, "!")`varsstringiferr:=db.QueryRow(query, "World").Scan(&s); err!=nil {
panic(err)
}
fmt.Println(s)
}

Let's generate a list of the SQL statements used in your package:

$ prep -f github.com/hexdigest/prepdemo
$ cat prepared_statements.go

//go:generate prep -f github.com/hexdigest/prepdemopackage main
varprepStatements= []string{
"SELECT CONCAT(\"Hello \", ?, \"!\")",
}

Using prepared statements

funcmain() {
sqlDB, err:=sql.Open("mysql", "root:root@tcp(localhost:3306)/mysql")
iferr!=nil {
panic(err)
}
db, err:=prep.NewConnection(sqlDB, prepStatements)
iferr!=nil {
panic(err)
}
constquery=`SELECT CONCAT("Hello ", ?, "!")`varsstringiferr:=db.QueryRow(query, "World").Scan(&s); err!=nil {
panic(err)
}
fmt.Println(s)
}

Take a look at the line:

db, err:=prep.NewConnection(sqlDB, prepStatements)

It instruments your connection with prepared statements found by the generator. The generated code already contains //go:generate instruction, so in order to update the statements list you can simply run:

$ go generate

Some synthetic benchmarks

$ go test -bench=.
BenchmarkPostgresWithoutPreparedStatements-4 20000 59941 ns/op 1183 B/op 32 allocs/op
BenchmarkPostgresWithPreparedStatements-4 50000 41560 ns/op 1021 B/op 26 allocs/op
BenchmarkMySQLWithoutPreparedStatements-4 50000 26454 ns/op 827 B/op 23 allocs/op
BenchmarkMySQLWithPreparedStatements-4 200000 9509 ns/op 634 B/op 19 allocs/op
PASS
ok github.com/hexdigest/prep	7.884s