README
¶
Package cloudeng.io/file/checkpoint
import cloudeng.io/file/checkpoint
Package checkpoint provides a mechanism for checkpointing the state of an ongoing operation. An operation is defined as any application activity that can be meaningfully broken into smaller steps and that can be resumed from one of those steps. The record of the successful completion of each step is recorded as a 'checkpoint'.
Types
Type Operation
type Operation interface {
// Checkpoint records the successful completion of a step in the
// operation.
Checkpoint(ctx context.Context, label string, data []byte) (id string, err error)
// Latest reads the latest recorded checkpoint.
Latest(ctx context.Context) ([]byte, error)
// Complete removes all checkpoints since the operation is
// deemed to be have comleted successfully.
Complete(ctx context.Context) error
// Load reads the checkpoint with the specified id, the id
// must have been returned by an earlier call to Checkpoint.
Load(ctx context.Context, id string) ([]byte, error)
}
Operation is the interface for checkpointing an operation.
Functions
func NewDirectoryOperation(dir string) (Operation, error)
NewDirectoryOperation returns an implementation of Operation that uses a directory on the local file system to record checkpoints. This implementation locks the directory using os.Lockedfile and rescans it on each call to Checkpoint to determine the latest entry. Consequently it is not well suited to very large numbers of checkpoints.
Documentation
¶
Overview ¶
Package checkpoint provides a mechanism for checkpointing the state of an ongoing operation. An operation is defined as any application activity that can be meaningfully broken into smaller steps and that can be resumed from one of those steps. The record of the successful completion of each step is recorded as a 'checkpoint'.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Operation ¶
type Operation interface {
Init(ctx context.Context, root string) error
// Clear all existing checkpoints.
Clear(context.Context) error
// Compact removes all but the most recent checkpoint and
// renames as the first checkpoint in the sequence.
Compact(ctx context.Context, label string) error
// Checkpoint records the successful completion of a step in the
// operation.
Checkpoint(ctx context.Context, label string, data []byte) (id string, err error)
// Latest reads the latest recorded checkpoint.
Latest(ctx context.Context) ([]byte, error)
// Complete removes all checkpoints since the operation is
// deemed to be have comleted successfully.
Complete(ctx context.Context) error
// Load reads the checkpoint with the specified id, the id
// must have been returned by an earlier call to Checkpoint.
Load(ctx context.Context, id string) ([]byte, error)
}
Operation is the interface for checkpointing an operation.
func NewDirectoryOperation ¶
func NewDirectoryOperation() Operation
NewDirectoryOperation returns an implementation of Operation that uses a directory on the local file system to record checkpoints. This implementation locks the directory using os.Lockedfile and rescans it on each call to Checkpoint to determine the latest entry. Consequently it is not well suited to very large numbers of checkpoints.
Source Files