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)) } // RemoveResourceInstanceChange searches the set of resource instance changes // for one matching the given address and generation, and removes it from the // set if it exists. func (cs *ChangesSync) RemoveResourceInstanceChange(addr addrs.AbsResourceInstance, gen states.Generation) { if cs == nil { panic("RemoveResourceInstanceChange on nil ChangesSync") } cs.lock.Lock() defer cs.lock.Unlock() dk := states.NotDeposed if realDK, ok := gen.(states.DeposedKey); ok { dk = realDK } addrStr := addr.String() for i, r := range cs.changes.Resources { if r.Addr.String() != addrStr || r.DeposedKey != dk { continue } copy(cs.changes.Resources[i:], cs.changes.Resources[i+1:]) cs.changes.Resources = cs.changes.Resources[:len(cs.changes.Resources)-1] return } }