| package statemgr |
| |
| import ( |
| "fmt" |
| |
| "github.com/hashicorp/terraform/internal/states" |
| "github.com/hashicorp/terraform/internal/states/statefile" |
| ) |
| |
| // PlannedStateUpdate is a special helper to obtain a statefile representation |
| // of a not-yet-written state snapshot that can be written later by a call |
| // to the companion function WritePlannedStateUpdate. |
| // |
| // The statefile object returned here has an unusual interpretation of its |
| // metadata that is understood only by WritePlannedStateUpdate, and so the |
| // returned object should not be used for any other purpose. |
| // |
| // If the state manager implements Locker then it is the caller's |
| // responsibility to hold the lock at least for the duration of this call. |
| // It is not safe to modify the given state concurrently while |
| // PlannedStateUpdate is running. |
| func PlannedStateUpdate(mgr Transient, planned *states.State) *statefile.File { |
| ret := &statefile.File{ |
| State: planned.DeepCopy(), |
| } |
| |
| // If the given manager uses snapshot metadata then we'll save that |
| // in our file so we can check it again during WritePlannedStateUpdate. |
| if mr, ok := mgr.(PersistentMeta); ok { |
| m := mr.StateSnapshotMeta() |
| ret.Lineage = m.Lineage |
| ret.Serial = m.Serial |
| } |
| |
| return ret |
| } |
| |
| // WritePlannedStateUpdate is a companion to PlannedStateUpdate that attempts |
| // to apply a state update that was planned earlier to the given state |
| // manager. |
| // |
| // An error is returned if this function detects that a new state snapshot |
| // has been written to the backend since the update was planned, since that |
| // invalidates the plan. An error is returned also if the manager itself |
| // rejects the given state when asked to store it. |
| // |
| // If the returned error is nil, the given manager's transient state snapshot |
| // is updated to match what was planned. It is the caller's responsibility |
| // to then persist that state if the manager also implements Persistent and |
| // the snapshot should be written to the persistent store. |
| // |
| // If the state manager implements Locker then it is the caller's |
| // responsibility to hold the lock at least for the duration of this call. |
| func WritePlannedStateUpdate(mgr Transient, planned *statefile.File) error { |
| // If the given manager uses snapshot metadata then we'll check to make |
| // sure no new snapshots have been created since we planned to write |
| // the given state file. |
| if mr, ok := mgr.(PersistentMeta); ok { |
| m := mr.StateSnapshotMeta() |
| if planned.Lineage != "" { |
| if planned.Lineage != m.Lineage { |
| return fmt.Errorf("planned state update is from an unrelated state lineage than the current state") |
| } |
| if planned.Serial != m.Serial { |
| return fmt.Errorf("stored state has been changed by another operation since the given update was planned") |
| } |
| } |
| } |
| |
| return mgr.WriteState(planned.State) |
| } |