mesos-operator-api-client

A generic client to listen to the Mesos Operator API's events.

Usage

Install as a dependency like this:

npm install mesos-operator-api-client --save

Master client

The Master client can be used to connect to the Mesos Operator API like.

Events

Known Mesos Operator API events

As of the Mesos Operator API documentation and the Mesos master.proto there are currently the following events:

• SUBSCRIBED
• TASK_ADDED
• TASK_UPDATED
• AGENT_ADDED
• AGENT_REMOVED

Those events will be emitted by this client as well if they occur.

Internal events

The Mesos Operator API events slient itself emits the following events:

• subscribed: Is emitted after a successful subscription to the Mesos Operator API.
• unsubscribed: Is emitted after unsubscribe() is called.
• reconciled: Is emitted after reconcile() is called. This queries the Operator API with a separate call to the GET_STATE method.
• error: Is emitted in case of internal or upstream errors.

Using the client

Options

You can specify the following properties when instantiating the Mesos Operator API events client:

• masterHost: The Mesos Master hostname (or ip address). Default is leader.mesos.
• masterPort: The Mesos Master port. Default is 5050.
• masterProtocol: The Mesos Operator API protocol (http or https). Default is http.
• masterApiUri: The relative path where the Mesos Operator API endpoint can be found. Default is /api/v1.
• masterConnectionTimeout: The time in milliseconds after which the connection to the Mesos Master is deemed as timed out. Default is 5000.
• eventTypes: An array of event types emitted by the Mesos Master (see above for a list). Default is ["SUBSCRIBED", "TASK_ADDED", "TASK_UPDATED", "AGENT_ADDED", "AGENT_REMOVED"].
• handlers: A map object consisting of handler functions for the individual Mesos Operator API events. See below for an explanation. No defaults.

Methods for events

The Mesos Operator API events client only exposes the subscribe() and the unsubscribe() methods. You can catch all above events via on(<eventType>, function (data) { ... }.

Supported methods for specific Operator API calls

The callback(error, data) function is optional, you need to add it only if you directly want to handle the results. Otherwise, those methods will trigger an event (starting with received_ appended by the lowercase method name, e.g. for GET_STATE is received_get_state), which applications can listen to to receive the responses in an asynchronous way.

• getHealth(callback): This calls the GET_HEALTH method.
• getFlags(callback): This calls the GET_FLAGS method.
• getVersion(callback): This calls the GET_VERSION method.
• getMetrics(callback): This calls the GET_METRICS method.
• getLoggingLevel(callback): This calls the GET_LOGGING_LEVEL method.
• getState(callback): This calls the GET_STATE method.
• getAgents(callback): This calls the GET_AGENTS method.
• getFrameworks(callback): This calls the GET_FRAMEWORKS method.
• getExecutors(callback): This calls the GET_EXECUTORS method.
• getTasks(callback): This calls the GET_TASKS method.
• getRoles(callback): This calls the GET_ROLES method.
• getWeights(callback): This calls the GET_WEIGHTS method.
• getMaster(callback): This calls the GET_MASTER method.
• getMaintenanceStatus(callback): This calls the GET_MAINTENANCE_STATUS method.
• getMaintenanceSchedule(callback): This calls the GET_MAINTENANCE_SCHEDULE method.
• getQuota(callback): This calls the GET_QUOTA method.

Event handler functions

The custom event handler functions can be configured by setting a map object as handlers property during the instantiation. Each map object's property represents a event handling function. The property name needs to match on of the Marathon event types from the list of known Marathon events.

This is an example handlers map object:

{ // Specify the custom event handlers
    "TASK_ADDED": function (data) {
        console.log("We have a new TASK_ADDED event!");
    },
    "TASK_UPDATED": function (data) {
        console.log("We have a new TASK_UPDATED event!");
    }
}

The function arguments are:

• data: The emitted data for the respective event

Example code

For a complete example, have a look at examples/masterExample.js.

"use strict";
 
// Use the MesosOperatorApiClient
const MasterClient = require("mesos-operator-api-client");
 
// Create MesosOperatorApiClient instance
const eventsClient = new MasterClient({
    masterHost: "172.17.11.101" // Replace with your Mesos Leader hostname or ip address
});
 
// Wait for "subscribed" event
eventsClient.on("subscribed", function () {
    console.log("Subscribed to the Mesos Operator API events!");
    // Call GET_AGENTS
    eventsClient.getAgents(function (err, data) {
        console.log("Got result for GET_AGENTS");
        console.log(JSON.stringify(data));
    });
    // Do a reconcile after 3000ms. Demo!
    setTimeout(function () {
        eventsClient.reconcile();
    }, 3000);
});
 
// Wait for "unsubscribed" event
eventsClient.on("unsubscribed", function () {
    console.log("Unsubscribed from the Mesos Operator API events!");
});
 
// Catch error events
eventsClient.on("error", function (errorObj) {
    console.log("Got an error");
    console.log(JSON.stringify(errorObj));
});
 
// Log SUBSCRIBED event
eventsClient.on("SUBSCRIBED", function (eventObj) {
    console.log("Got SUBSCRIBED");
    console.log(JSON.stringify(eventObj));
});
 
// Log TASK_ADDED event
eventsClient.on("TASK_ADDED", function (eventObj) {
    console.log("Got TASK_ADDED");
    console.log(JSON.stringify(eventObj));
});
 
// Log TASK_UPDATED event
eventsClient.on("TASK_UPDATED", function (eventObj) {
    console.log("Got TASK_UPDATED");
    console.log(JSON.stringify(eventObj));
});
 
// Log AGENT_ADDED event
eventsClient.on("AGENT_ADDED", function (eventObj) {
    console.log("Got AGENT_ADDED");
    console.log(JSON.stringify(eventObj));
});
 
// Log AGENT_REMOVED event
eventsClient.on("AGENT_REMOVED", function (eventObj) {
    console.log("Got AGENT_REMOVED");
    console.log(JSON.stringify(eventObj));
});
 
// Subscribe to Mesos Operator API events
eventsClient.subscribe();
 
// Unsubscribe after 10sec. Demo!
setTimeout(function () {
    eventsClient.unsubscribe();
}, 10000);

Agent client

Using the client

Options

You can specify the following properties when instantiating the Mesos Operator API events client:

• agentHost: The Mesos Agent hostname (or ip address). Default is 127.0.0.1.
• agentPort: The Mesos Agent port. Default is 5051.
• agentProtocol: The Mesos Operator API protocol (http or https). Default is http.
• agentApiUri: The relative path where the Mesos Operator API endpoint can be found. Default is /api/v1.
• agentConnectionTimeout: The time in milliseconds after which the connection to the Mesos Agent is deemed as timed out. Default is 5000.

Example code

For a complete example, have a look at examples/agentExample.js.

"use strict";
 
// Use the agentClient
const AgentClient = require("mesos-operator-api-client").agentClient;
 
// Create agentClient instance
const agent = new AgentClient({
    agentHost: "172.17.11.102"
});
 
// Call GET_HEALTH
agent.getHealth(function (err, data) {
    console.log(JSON.stringify(data));
});

Supported methods for specific Operator API calls

The callback(error, data) function is optional, you need to add it only if you directly want to handle the results. Otherwise, those methods will trigger an event (starting with received_ appended by the lowercase method name, e.g. for GET_STATE is received_get_state), which applications can listen to to receive the responses in an asynchronous way.

• getHealth(callback): This calls the GET_HEALTH method.
• getFlags(callback): This calls the GET_FLAGS method.
• getVersion(callback): This calls the GET_VERSION method.
• getMetrics(callback): This calls the GET_METRICS method.
• getState(callback): This calls the GET_STATE method.
• getContainers(callback): This calls the GET_CONTAINERS method.
• getFrameworks(callback): This calls the GET_FRAMEWORKS method.
• getExecutors(callback): This calls the GET_EXECUTORS method.
• getTasks(callback): This calls the GET_TASKS method.
• getAgent(callback): This calls the GET_AGENT method.