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
func main() {
db, err := sql.Open("mysql", "user:pass@tcp(localhost:3306)/mysql")
if err != nil {
panic(err)
}
const query = `SELECT CONCAT("Hello ", ?, "!")`
var s string
if err := 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/prepdemo
package main
var prepStatements = []string{
"SELECT CONCAT(\"Hello \", ?, \"!\")",
}Using prepared statements
func main() {
sqlDB, err := sql.Open("mysql", "root:root@tcp(localhost:3306)/mysql")
if err != nil {
panic(err)
}
db, err := prep.NewConnection(sqlDB, prepStatements)
if err != nil {
panic(err)
}
const query = `SELECT CONCAT("Hello ", ?, "!")`
var s string
if err := 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 generateSome 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