snapshot

snapshot

Sometimes you need to experiment.

package main

import (
  "fmt"
  "github.com/jhunt/go-snapshot"
)

type Thing struct {
  Name  string
  Value int
  On    bool
}

int main() {
  thing := Thing{
    Name:  "widget",
    Value: 4,
    On:    true,
  }

  sn, _ := snapshot.Take(&thing)

  ok := TrySomethingCrazy(&thing)
  if (ok) {
    fmt.Printf("something crazy worked!  %s = %d (on is %v)\n",
               thing.Name, thing,Value, thing.On)
    return
  }

  sn.Revert()

  ok = TrySomethingEvenCrazier(&thing)
  if (ok) {
    fmt.Printf("something EVEN CRAZIER worked!  %s = %d (on is %v)\n",
               thing.Name, thing,Value, thing.On)
    return
  }

  sn.Revert()
  fmt.Printf("nothing worked!  %s = %d (on is %v)\n",
             thing.Name, thing,Value, thing.On)
}

snapshot lets you take a point-in-time, deep-copy of an arbitrary value, be it a string, boolean, number, struct, etc., and be able to return to that point in time at some point in the future.

Contributing

This code is licensed MIT. Enjoy.

If you find a bug, please raise a Github Issue first, before submitting a PR.

When you do work up a patch, keep in mind that we have a fairly extensive test suite in snapshot_test.go. I don't care all that much about code coverage, but we do have >90% C0 code coverage on the current tests suite, and I'd like to keep it that way.

(That's not to say we've caught 90% of the bugs, but it's better than nothin')

Happy Hacking!