terraform/plans/changes_sync.go

64 lines
2.2 KiB
Go

package plans
import (
"fmt"
"sync"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/states"
)
// ChangesSync is a wrapper around a Changes that provides a concurrency-safe
// interface to insert new changes and retrieve copies of existing changes.
//
// Each ChangesSync is independent of all others, so all concurrent writers
// to a particular Changes must share a single ChangesSync. Behavior is
// undefined if any other caller makes changes to the underlying Changes
// object or its nested objects concurrently with any of the methods of a
// particular ChangesSync.
type ChangesSync struct {
lock sync.Mutex
changes *Changes
}
// AppendResourceInstanceChange records the given resource instance change in
// the set of planned resource changes.
//
// The caller must ensure that there are no concurrent writes to the given
// change while this method is running, but it is safe to resume mutating
// it after this method returns without affecting the saved change.
func (cs *ChangesSync) AppendResourceInstanceChange(changeSrc *ResourceInstanceChangeSrc) {
if cs == nil {
panic("AppendResourceInstanceChange on nil ChangesSync")
}
cs.lock.Lock()
defer cs.lock.Unlock()
s := changeSrc.DeepCopy()
cs.changes.Resources = append(cs.changes.Resources, s)
}
// GetResourceInstanceChange searches the set of resource instance changes for
// one matching the given address and generation, returning it if it exists.
//
// If no such change exists, nil is returned.
//
// The returned object is a deep copy of the change recorded in the plan, so
// callers may mutate it although it's generally better (less confusing) to
// treat planned changes as immutable after they've been initially constructed.
func (cs *ChangesSync) GetResourceInstanceChange(addr addrs.AbsResourceInstance, gen states.Generation) *ResourceInstanceChangeSrc {
if cs == nil {
panic("GetResourceInstanceChange on nil ChangesSync")
}
cs.lock.Lock()
defer cs.lock.Unlock()
if gen == states.CurrentGen {
return cs.changes.ResourceInstance(addr).DeepCopy()
}
if dk, ok := gen.(states.DeposedKey); ok {
return cs.changes.ResourceInstanceDeposed(addr, dk).DeepCopy()
}
panic(fmt.Sprintf("unsupported generation value %#v", gen))
}