dsn.go

package dsn

type DSN string

func (d DSN) String() string {
        i := strings.Index(string(d), "&password=")
        if i == -1 {
                return string(d)
        }
        ret := []byte(d)
        for i += len("&password="); i < len(d) && ret[i] != '&'; i++ {
                ret[i] = '*'
        }
        return string(ret)
}

dsn_test.go

package dsn

import (
        "testing"

        "github.com/stretchr/testify/assert"
)

func TestDSN(t *testing.T) {
        var tc = []struct {
                Name   string
                Input  string
                Expect string
        }{
                {
                        Name:   "sanity",
                        Input:  "asdf&password=werweq",
                        Expect: "asdf&password=******",
                },
                {
                        Name:   "middle",
                        Input:  "asdf&password=werweq&count=4",
                        Expect: "asdf&password=******&count=4",
                },
                {
                        Name:   "empty pw",
                        Input:  "asdf&password=&asdf=qwer",
                        Expect: "asdf&password=&asdf=qwer",
                },
                {
                        Name:   "start of string",
                        Input:  "&password=werweq&count=4",
                        Expect: "&password=******&count=4",
                },
                {
                        Name:   "only contents",
                        Input:  "&password=werweq",
                        Expect: "&password=******",
                },
                {
                        Name:   "empty string",
                        Input:  "",
                        Expect: "",
                },
                {
                        Name:   "no password",
                        Input:  "asdf/&adfwe=werw",
                        Expect: "asdf/&adfwe=werw",
                },
        }

        for _, c := range tc {
                t.Run(c.Name, func(t *testing.T) {
                        x := DSN(c.Input)
                        assert.Equal(t, c.Input, string(x), "string cast should keep original")
                        assert.Equal(t, c.Expect, x.String(), "should obfuscate password")
                })
        }
}