prep

Prep finds all SQL statements in a Go package and instruments db connection with prepared statements

Programming language: Go

License: Apache License 2.0

Tags: Database    

README

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:[email protected](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:[email protected](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 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