Class: AsyncClient

AsyncClient

A zookeeper client that has methods that return promises.

Constructor

new AsyncClient(client)

Creates a new AsyncClient for communicating with zookeeper. This object will expose all the methods of the underlying zookeeper client, but also expose a number of methods that return promises.
Parameters:
Name Type Description
client Client the underlying zookeeper client created by createClient.
Source:
Example
const zk = require('node-zookeeper-client-async');

const client = zk.createAsyncClient("127.0.0.1:2181");

// connect to the server
await client.connectAsync();
console.log('connected!');

// create a node
const rootPath = await client.mkdirpAsync('/test');
console.log(`created ${rootPath}`)

// add some ephemeral nodes
await client.createAsync('/test/counter-', Buffer.from('first'), null, zk.CreateMode.EPHEMERAL_SEQUENTIAL);
await client.createAsync('/test/counter-', Buffer.from('second'), null, zk.CreateMode.EPHEMERAL_SEQUENTIAL);

// list the nodes
const nodes = await client.getChildrenAsync('/test');

// print stuff to console
console.log(`${rootPath} has the children:`)
    await Promise.all(nodes.map(async node => {
    const data = await client.getDataAsync(`/test/${node}`);
    console.log(`  ${node}: ${data.data}`);
}));

// delete everything
await client.rmrfAsync(rootPath);

// shut down
await client.closeAsync();
console.log('disconnected');

Methods

closeAsync() → {Promise}

Close this client. Once the client is closed, its session becomes invalid. All the ephemeral nodes in the ZooKeeper server associated with the session will be removed. The watchers left on those nodes (and on their parents) will be triggered. Resolves true when the client disconnects, resolves false if the client is already disconnected.
Source:
Returns:
resolves when disconnected. Does not reject.
Type
Promise

connectAsync() → {Promise}

Initiate the connection to the provided server list (ensemble). The client will pick an arbitrary server from the list and attempt to connect to it. If the establishment of the connection fails, another server will be tried (picked randomly) until a connection is established or close method is invoked.
Source:
Returns:
resolves on connect. Rejects with message on failure.
Type
Promise

createAsync(path, data, acls, mode) → {Promise}

Create a node with given path, data, acls and mode. Resolves the path name if successful, resolves false if the path already exists, and rejects for anything else going wrong
Parameters:
Name Type Default Description
path String Path of the node.
data Buffer null The data buffer, optional, defaults to null.
acls ACL null An array of ACL objects, optional, defaults to ACL.OPEN_ACL_UNSAFE.
mode CreateMode null The creation mode, optional, defaults to CreateMode.PERSISTENT.
Source:
Returns:
resolves with the path of the created item. Rejects with an error if something goes wrong.
Type
Promise

existsAsync(path) → {Promise}

For the given node path, retrieve the children list and the stat. The children will be an unordered list of strings. Resolves the stat object if the node exists, resolves null if it does not exist, rejects if anything goes wrong.
Parameters:
Name Type Description
path string the Path of the node.
Source:
Returns:
Type
Promise

getACLAsync(path) → {Promise}

Retrieve the list of ACL and stat of the node of the given path. Will resolve an object with acls as a list of ACL objects and stat as the stat for the node. Will resolve null if the node does not exist and will reject if anything goes wrong.
Parameters:
Name Type Description
path string the Path of the node.
Source:
Returns:
Type
Promise

getChildrenAsync(path) → {Promise}

For the given node path, retrieve the children list and the stat. The children will be an unordered list of strings. Resolved the children if the node exists, resolves null if the node does not exist. Rejects if anything goes wrong.
Parameters:
Name Type Description
path string the Path of the node.
Source:
Returns:
Type
Promise

getDataAsync(path) → {Promise}

Retrieve the data and the stat of the node of the given path. Resolves an object containing data as a Buffer object and stat as the stat object. Resolves null if the node does not exist. Rejects if anything goes wrong.
Parameters:
Name Type Description
path string the Path of the node.
Source:
Returns:
Type
Promise

mkdirpAsync(path, data, acls, mode) → {Promise}

Create given path in a way similar to mkdir -p. Will resolve the path if the node is created and will reject if anything goes wrong.
Parameters:
Name Type Default Description
path string the Path of the node.
data Buffer null The data buffer, optional, defaults to null.
acls Array.<ACL> null array of ACL objects, optional, defaults to ACL.OPEN_ACL_UNSAFE
mode CreateMode null The creation mode, optional, defaults to CreateMode.PERSISTENT
Source:
Returns:
Type
Promise

removeAsync(path, version) → {Promise}

Delete a node with the given path and version. If version is provided and not equal to -1, the request will fail when the provided version does not match the server version. Resolves true if the node is deleted. Resolves false if the node does not exist. Rejects if the node has children, if the version does not match, or for any other result.
Parameters:
Name Type Description
path String Path of the node.
version Number The version of the node, optional, defaults to -1.
Source:
Returns:
Type
Promise

rmrfAsync(path) → {Promise}

Remove a given path in a way similar to rm -rf. Will resolve if the node is deleted or does not exist and reject if anything goes wrong.
Parameters:
Name Type Description
path string the Path of the node.
Source:
Returns:
Type
Promise

setACLAsync(path, acls, version)

Set the ACL for the node of the given path if such a node exists and the given version (optional) matches the version of the node on the server. (if the given version is -1, it matches any versions). Will resolve on success and reject if anything goes wrong or the node does not exist.
Parameters:
Name Type Description
path string the Path of the node.
acls Array.<ACL> An array of ACL instances to set on the node.
version Number the version to set. -1 (default) to match any version.
Source:

setDataAsync(path, data, version) → {Promise}

Set the data for the node of the given path if such a node exists and the optional given version matches the version of the node (if the given version is -1, it matches any node's versions). Will resolve the stat of the node if successful. Will reject if unsuccessful or if the node does not exist.
Parameters:
Name Type Description
path string the Path of the node.
data Buffer the data to set on the node.
version Number the version to set. -1 (default) to match any version.
Source:
Returns:
Type
Promise

transaction() → {AsyncTransaction}

Create and return a new Transaction instance which provides a builder object that can be used to construct and commit a set of operations atomically.
Source:
Returns:
Type
AsyncTransaction