github.com/jrasell/terraform@v0.6.17-0.20160523115548-2652f5232949/state/state.go (about)

     1  package state
     2  
     3  import (
     4  	"github.com/hashicorp/terraform/terraform"
     5  )
     6  
     7  // State is the collection of all state interfaces.
     8  type State interface {
     9  	StateReader
    10  	StateWriter
    11  	StateRefresher
    12  	StatePersister
    13  }
    14  
    15  // StateReader is the interface for things that can return a state. Retrieving
    16  // the state here must not error. Loading the state fresh (an operation that
    17  // can likely error) should be implemented by RefreshState. If a state hasn't
    18  // been loaded yet, it is okay for State to return nil.
    19  type StateReader interface {
    20  	State() *terraform.State
    21  }
    22  
    23  // StateWriter is the interface that must be implemented by something that
    24  // can write a state. Writing the state can be cached or in-memory, as
    25  // full persistence should be implemented by StatePersister.
    26  type StateWriter interface {
    27  	WriteState(*terraform.State) error
    28  }
    29  
    30  // StateRefresher is the interface that is implemented by something that
    31  // can load a state. This might be refreshing it from a remote location or
    32  // it might simply be reloading it from disk.
    33  type StateRefresher interface {
    34  	RefreshState() error
    35  }
    36  
    37  // StatePersister is implemented to truly persist a state. Whereas StateWriter
    38  // is allowed to perhaps be caching in memory, PersistState must write the
    39  // state to some durable storage.
    40  type StatePersister interface {
    41  	PersistState() error
    42  }