Merge pull request #10134 from hashicorp/b-shadow-close

helper/shadow: Close for auto-closing all values
This commit is contained in:
Mitchell Hashimoto 2016-11-15 08:54:42 -08:00 committed by GitHub
commit b6f5eb6371
3 changed files with 150 additions and 17 deletions

80
helper/shadow/closer.go Normal file
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@ -0,0 +1,80 @@
package shadow
import (
"fmt"
"io"
"reflect"
"github.com/hashicorp/go-multierror"
"github.com/mitchellh/reflectwalk"
)
// Close will close all shadow values within the given structure.
//
// This uses reflection to walk the structure, find all shadow elements,
// and close them. Currently this will only find struct fields that are
// shadow values, and not slice elements, etc.
func Close(v interface{}) error {
// We require a pointer so we can address the internal fields
val := reflect.ValueOf(v)
if val.Kind() != reflect.Ptr {
return fmt.Errorf("value must be a pointer")
}
// Walk and close
var w closeWalker
if err := reflectwalk.Walk(v, &w); err != nil {
return err
}
return w.Err
}
type closeWalker struct {
Err error
}
func (w *closeWalker) Struct(reflect.Value) error {
// Do nothing. We implement this for reflectwalk.StructWalker
return nil
}
func (w *closeWalker) StructField(f reflect.StructField, v reflect.Value) error {
// Not sure why this would be but lets avoid some panics
if !v.IsValid() {
return nil
}
// Empty for exported, so don't check unexported fields
if f.PkgPath != "" {
return nil
}
// Verify the io.Closer is in this package
typ := v.Type()
if typ.PkgPath() != "github.com/hashicorp/terraform/helper/shadow" {
return nil
}
// We're looking for an io.Closer
raw := v.Interface()
if raw == nil {
return nil
}
closer, ok := raw.(io.Closer)
if !ok && v.CanAddr() {
closer, ok = v.Addr().Interface().(io.Closer)
}
if !ok {
return reflectwalk.SkipEntry
}
// Close it
if err := closer.Close(); err != nil {
w.Err = multierror.Append(w.Err, err)
}
// Don't go into the struct field
return reflectwalk.SkipEntry
}

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@ -0,0 +1,69 @@
package shadow
import (
"testing"
"time"
)
func TestClose(t *testing.T) {
var foo struct {
A Value
B KeyedValue
}
if err := Close(&foo); err != nil {
t.Fatalf("err: %s", err)
}
if v := foo.A.Value(); v != ErrClosed {
t.Fatalf("bad: %#v", v)
}
if v := foo.B.Value("foo"); v != ErrClosed {
t.Fatalf("bad: %#v", v)
}
}
func TestClose_nonPtr(t *testing.T) {
var foo struct{}
if err := Close(foo); err == nil {
t.Fatal("should error")
}
}
func TestClose_unexported(t *testing.T) {
var foo struct {
A Value
b Value
}
if err := Close(&foo); err != nil {
t.Fatalf("err: %s", err)
}
if v := foo.A.Value(); v != ErrClosed {
t.Fatalf("bad: %#v", v)
}
// Start trying to get the value
valueCh := make(chan interface{})
go func() {
valueCh <- foo.b.Value()
}()
// We should not get the value
select {
case <-valueCh:
t.Fatal("shouldn't receive value")
case <-time.After(10 * time.Millisecond):
}
// Set the value
foo.b.Close()
val := <-valueCh
// Verify
if val != ErrClosed {
t.Fatalf("bad: %#v", val)
}
}

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@ -2,7 +2,6 @@ package terraform
import ( import (
"fmt" "fmt"
"io"
"log" "log"
"sync" "sync"
@ -309,22 +308,7 @@ type shadowResourceProviderShared struct {
} }
func (p *shadowResourceProviderShared) Close() error { func (p *shadowResourceProviderShared) Close() error {
closers := []io.Closer{ return shadow.Close(p)
&p.CloseErr, &p.Input, &p.Validate,
&p.Configure, &p.ValidateResource, &p.Apply, &p.Diff,
&p.Refresh, &p.ValidateDataSource, &p.ReadDataDiff,
}
for _, c := range closers {
// This should never happen, but we don't panic because a panic
// could affect the real behavior of Terraform and a shadow should
// never be able to do that.
if err := c.Close(); err != nil {
return err
}
}
return nil
} }
func (p *shadowResourceProviderShadow) CloseShadow() error { func (p *shadowResourceProviderShadow) CloseShadow() error {