ucarion / redact

A Golang library for redacting sensitive values from a struct

redact

redact is a Golang library for redacting sensitive values from a struct. This is useful when you're logging requests and responses on a server, but some payloads contain secrets or other values that shouldn't be logged.

Example

redact provides a Redact function that takes a path and the value you want to mutate. It works on struct elements:

import "github.com/ucarion/redact"

type User struct {
  Name string
  Password string
}

user := User{Name: "John", Password: "letmein"}
fmt.Println(user) // {John letmein}

redact.Redact([]string{"Password"}, &user)
fmt.Println(user) // {John }

This works even if the data you want to redact is nested:

type CreateUserRequest struct {
  RequestID string
  User      User
}

req := CreateUserRequest{RequestID: "abc", User: User{Name: "John", Password: "letmein"}}
fmt.Println(req) // {abc {John letmein}}

redact.Redact([]string{"User", "Password"}, &req)
fmt.Println(req) // {abc {John }}

It also works on arrays and slices. In that case, every element of the array or slice gets recursively redacted:

users := []User{
  User{Name: "John", Password: "letmein"},
  User{Name: "Mary", Password: "123456"},
}

fmt.Println(users) // [{John letmein}, {Mary 123456}]

redact.Redact([]string{"Password"}, &users)
fmt.Println(users) // [{John }, {Mary }]

It also works on maps in a way similar to structs.

user := map[string]string{
  "Name": "John",
  "Password": "letmein",
}
fmt.Println(user) // {Name: John, Password: letmein}

redact.Redact([]string{"Password"}, &user)
fmt.Println(user) // {Name: John, Password: }

Note, however, that Go does not support mutating map elements. That's not something any package can work around. So if you want to mutate elements of a map (in the example above, we replaced Password, not modified it). You'll have to make the map elements be pointers:

users := map[string]*User{
  "a": &User{Name: "John", Password: "letmein"},
}
fmt.Println(users["a"]) // &{John letmein}

redact.Redact([]string{"a", "Password"}, &users)
fmt.Println(users["a"]) // &{John }