file Key-Value Store driver¶

The file driver uses the filesystem as a key-value store directly. A key directly specifies a path under a given root directory; the value is stored as the file contents.

Locking provided by the filesystem is used to safely allow concurrent access from multiple processes. (The locking protocol used does not block readers.) Provided that shared locking is supported, concurrent access from multiple machines to a network filesystem is also safe.

json kvstore/file : object¶

JSON specification of file-backed key-value store.

Extends:¶

• KvStore — Key-value store specification.

Required members:¶

driver : "file"¶

path : string¶

Path to root directory on local filesystem.

Optional members:¶

context : Context¶

Specifies context resources that augment/override the parent context.

file_io_concurrency : ContextResource¶

Specifies or references a previously defined Context.file_io_concurrency.

json KvStoreUrl/file : string¶

file:// KvStore URL scheme

File-based key-value stores may be specified using the widely-supported file://path URL syntax.

Examples

URL representation	JSON representation
"file:///tmp/dataset/"	{"driver": "file", "path": "/tmp/dataset/"}
"file://C:/Users/abc/dataset/"	{"driver": "file", "path": "C:/Users/abc/dataset/"}

Extends:¶

• KvStoreUrl — URL representation of a key-value store.

Limitations¶