etcd-io__etcd/Documentation/etcd-file-system.md

#Etcd File System

Structure

[TODO]

Node

In Etcd, the Node is the rudimentary element constructing the whole. Currently Etcd file system is comprised in a Unix-like way of files and directories, and they are two kinds of nodes different in:

• File Node has data associated with it.
• Directory Node has children nodes associated with it.

Besides the file and directory difference, all nodes have common attributes and operations as follows:

Attributes:

• Expiration Time [optional]

The node will be deleted when it expires.

• ACL

The path of access control list of the node.

Operation:

• Get (path, recursive)

Get the content of the node

- If the node is a file, the data of the file will be returned.
- If the node is a directory, the child nodes of the directory will be returned.
- If recursive is true, it will recursively get the nodes of the directory.

• Set (path, value[optional], ttl [optional])

Set the value to a file. Set operation will help to create intermediate directories with no expiration time.

- If the value is given, set will create a file
- If the value is not given, set will crate a directory
- If ttl is given, the node will be deleted when it expires.

• Delete (path, recursive)

Delete the node of given path.

- If the node is a directory:
- If recursive is true, the operation will delete all nodes under the directory.
- If recursive is false, error will be returned.

• TestAndSet (path, prevValue [prevIndex], value, ttl)

Atomic test and set value to a file. If test succeeds, this operation will change the previous value of the file to the given value.

- If the prevValue is given, it will test against previous value of 
the node.
- If the prevValue is empty, it will test if the node is not existing.
- If the prevValue is not empty, it will test if the prevValue is equal to the current value of the file.
- If the prevIndex is given, it will test if the create/last modified index of the node is equal to prevIndex.

• Renew (path, ttl)

Set the node's expiration time to (current time + ttl)

ACL

[TODO]

User Group

[TODO]