taskcluster-client

TaskCluster Client

A taskcluster client library for node.js.

This client library is generated from the auto-generated API reference. You can create a Client class from a JSON reference object at runtime using taskcluster.createClient(reference). But there is also a set of builtin references from which Client classes are already constructed.

Calling API End-Points

To invoke an API end-point instantiate a taskcluster Client class, these are classes can be created from a JSON reference object, but a number of them are also built-in to this library. In the following example we instantiate an instance of the Queue Client class and use to to create a task.

var taskcluster = require('taskcluster-client');

// Instantiate the Queue Client class
var queue = new taskcluster.Queue({
  credentials: {
    clientId:     '...',
    accessToken:  '...'
  }
});

// Create task using the queue client
queue.createTask(task).then(function(result) {
  // status is a task status structure
  console.log(result.status);
});

The payload parameter is always a JSON object as documented by the REST API documentation. The methods always returns a promise for the response JSON object as documented in the REST API documentation.

Listening for Events

Many TaskCluster components publishes messages about current events over AMQP. The JSON reference object also contains meta-data about declared AMQP topic exchanges and their routing key construction. This is designed to make it easy to construct routing key patterns and parse routing keys from incoming messages.

The following example create a listener and instantiate an instance of the Client class QueueEvents which we use to find the exchange and create a routing pattern to listen for completion of a specific task. The taskCompleted method will construct a routing key pattern by using * or # for missing entries, pending on whether or not they are single word or multi-key entries.

var taskcluster = require('taskcluster-client');

// Create a listener (this creates a queue on AMQP)
var listener = new taskcluster.Listener({
  connectionString:   'amqp://...'
});

// Instantiate the QueueEvents Client class
var queueEvents = new taskcluster.QueueEvents();

// Bind to task-completed events from queue that matches routing key pattern:
//   '<myTaskId>.*.*.*.*.*.#'
listener.bind(queueEvents.taskCompleted({taskId: '<myTaskId>'}));

// Listen for messages
listener.on('message', function(message) {
  message.exchange        // Exchange from which message came
  message.payload         // Documented on docs.taskcluster.net
  message.routingKey      // Message routing key in string format
  message.routing.taskId  // Element from parsed routing key
  message.routing.runId   // ...
  message.redelivered     // True, if message has been nack'ed and requeued
  return new Promise(...);
});

// Start listening for events
listener.connect().then(function() {
  // Now listening
});

The listener creates a AMQP queue, on the server side and subscribes to messages on the queue. It's possible to use named queues, see details below. For details on routing key entries refer to documentation on docs.taskcluster.net.

Remark, API end-points and AMQP exchanges are typically documented in separate reference files. For this reason they also have separate Client classes, even if they are from the same component.

Documentation

The set of API entries listed below is generated from the builtin references. Detailed documentation with description, payload and result format details is available on docs.taskcluster.net.

On the documentation site entries often have a signature, you'll find that it matches the signatures below. Notice that all the methods returns a promise. A method with : void also returns a promise, that either resolves without giving a value or rejects with an error.

Methods in taskcluster.Auth

// Create Auth client instance with default baseUrl:
//  - http://auth.taskcluster.net/v1
var auth = new taskcluster.Auth(options);

• auth.inspect(clientId) : result
• auth.getCredentials(clientId) : result

Methods in taskcluster.Queue

// Create Queue client instance with default baseUrl:
//  - http://queue.taskcluster.net/v1
var queue = new taskcluster.Queue(options);

• queue.createTask(payload) : result
• queue.defineTasks(payload) : result
• queue.scheduleTask(taskId) : result
• queue.getTask(taskId) : result
• queue.getTaskStatus(taskId) : result
• queue.claimTask(taskId, payload) : result
• queue.requestArtifactUrls(taskId, payload) : result
• queue.reportTaskCompleted(taskId, payload) : result
• queue.claimWork(provisionerId, workerType, payload) : result
• queue.rerunTask(taskId) : result
• queue.getPendingTasks(provisionerId) : void
• queue.getAMQPConnectionString() : result

Methods in taskcluster.Scheduler

// Create Scheduler client instance with default baseUrl:
//  - http://scheduler.taskcluster.net/v1
var scheduler = new taskcluster.Scheduler(options);

• scheduler.createTaskGraph(payload) : result
• scheduler.extendTaskGraph(taskGraphId, payload) : result
• scheduler.getTaskGraphStatus(taskGraphId) : result
• scheduler.getTaskGraphInfo(taskGraphId) : result
• scheduler.inspectTaskGraph(taskGraphId) : result

Exchanges in taskcluster.QueueEvents

// Create QueueEvents client instance with default exchangePrefix:
//  - queue/v1/
var queueEvents = new taskcluster.QueueEvents(options);

• queueEvents.taskPending(routingKeyPattern) : binding-info
• queueEvents.taskRunning(routingKeyPattern) : binding-info
• queueEvents.taskCompleted(routingKeyPattern) : binding-info
• queueEvents.taskFailed(routingKeyPattern) : binding-info

Exchanges in taskcluster.SchedulerEvents

// Create SchedulerEvents client instance with default exchangePrefix:
//  - scheduler/v1/
var schedulerEvents = new taskcluster.SchedulerEvents(options);

• schedulerEvents.taskGraphRunning(routingKeyPattern) : binding-info
• schedulerEvents.taskGraphExtended(routingKeyPattern) : binding-info
• schedulerEvents.taskGraphBlocked(routingKeyPattern) : binding-info
• schedulerEvents.taskGraphFinished(routingKeyPattern) : binding-info

Create Client Class Dynamically

You can create a Client class from a reference JSON object as illustrated below:

var reference = {...}; // JSON from references.taskcluster.net/...

// Create Client class
var MyClient = taskcluster.createClient(reference);

// Instantiate an instance of MyClient
var myClient = new MyClient(options);

// Make a request with a method on myClient
myClient.myMethod(arg1, arg2, payload).then(function(result) {
  // ...
});

Configuration of API Invocations

There is a number of configuration options for Client which affects invocation of API end-points. These are useful if using a non-default server, for example when setting up a staging area or testing locally.

Configuring API BaseUrls

If you use the builtin API Client classes documented above you can configure the baseUrl when creating an instance of the client. As illustrated below:

var auth = new taskcluster.Auth({
  credentials:  {...},
  baseUrl:      "http://localhost:4040" // Useful for development and testing
});

Configuring Credentials

When creating an instance of a Client class the credentials can be provided in options. For example:

var auth = new taskcluster.Auth({
  credentials: {
    clientId:     '...',
    accessToken:  '...'
  }
});

You can also configure default options globally using taskcluster.config(options), as follows:

// Configure default options
taskcluster.config({
  credentials: {
    clientId:     '...',
    accessToken:  '...'
  }
});

// No credentials needed here
var auth = new taskcluster.Auth();

Delegated Authorization

If your client has the scope auth:can-delegate you can send requests with a scope set different from the one you have. This is useful when the scheduler performs a request on behalf of a task-graph, or when authentication takes place in a trusted proxy. See example below:

// Create delegating instance of Auth Client class
var auth = new taskcluster.Auth({
  credentials: {
    clientId:     '...',
    accessToken:  '...',
    delegating:   true,
    scopes:       ['scope', ...]  // For example task.scopes
  }
});

// This request is only successful if the set of scopes declared above
// allows the request to come through. The set of scopes the client has
// will not be used to authorize this request.
auth.getCredentials(someClientId).then(function(result) {
  // ...
});

We call this delegated authorization, because the trusted node that has the scope auth:can-delegate, delegates authorization of the request to API end-point.

Configuration of Exchange Bindings

When a taskcluster Client class is instantiated the option exchangePrefix may be given. This will replace the default exchangePrefix. This can be useful if deploying a staging area or similar. See example below:

// Instantiate the QueueEvents Client class
var queueEvents = new taskcluster.QueueEvents({
  exchangePrefix:     'staging-queue/v1/'
});

// This listener will now bind to: staging-queue/v1/task-completed
listener.bind(queueEvents.taskCompleted({taskId: '<myTaskId>'}));

Using the Listener

TODO:

var listener = new taskcluster.Listener({
  prefetch:           5,            // Number of tasks to process in parallel
  connectionString:   'amqp://...', // AMQP connection string
  // If no queue name is given, the queue is:
  //    exclusive, autodeleted and non-durable
  // If a queue name is given, the queue is:
  //    durable, not auto-deleted and non-exclusive
  queueName:          'my-queue',   // Queue name, undefined if none
  maxLength:          0,            // Max allowed queue size
});

listener.connect().then(...);       // Setup listener and start
listener.pause().then(...);         // Pause retrieval of new messages
listener.resume().then(...);        // Start getting new messages
listener.close();                   // Disconnect from AMQP

Updating Builtin APIs

When releasing a new version of the taskcluster-client library, we should always update the builtin references using utils/update-apis.js this maintenance script can be used to list, show, add, remove and update builtin API definitions.

When apis.json is updated, please run utils/generate-docs.js to update the documentation in this file.

##License The taskcluster client library is released on MPL 2.0.