What is applicationinsights?
The applicationinsights npm package is a powerful tool for monitoring and diagnosing performance issues in your applications. It provides a range of features for collecting telemetry data, tracking custom events, and monitoring dependencies, among other capabilities.
What are applicationinsights's main functionalities?
Telemetry Client
The Telemetry Client allows you to track custom events and metrics. This example demonstrates how to set up the client and track a custom event.
const appInsights = require('applicationinsights');
appInsights.setup('YOUR_INSTRUMENTATION_KEY').start();
const client = appInsights.defaultClient;
client.trackEvent({ name: 'my custom event', properties: { customProperty: 'custom value' } });
Request Tracking
Request Tracking automatically collects and sends telemetry data for incoming HTTP requests. This example shows how to set up a basic HTTP server with request tracking enabled.
const appInsights = require('applicationinsights');
appInsights.setup('YOUR_INSTRUMENTATION_KEY').start();
const http = require('http');
http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('Hello World\n');
}).listen(8080);
Dependency Tracking
Dependency Tracking allows you to monitor the performance and success of external dependencies. This example demonstrates how to manually track a dependency.
const appInsights = require('applicationinsights');
appInsights.setup('YOUR_INSTRUMENTATION_KEY').start();
const client = appInsights.defaultClient;
client.trackDependency({ target: 'http://example.com', name: 'GET /', data: 'http://example.com', duration: 100, resultCode: 200, success: true });
Exception Tracking
Exception Tracking captures and sends telemetry data for exceptions. This example shows how to track an exception.
const appInsights = require('applicationinsights');
appInsights.setup('YOUR_INSTRUMENTATION_KEY').start();
const client = appInsights.defaultClient;
try {
throw new Error('Test error');
} catch (e) {
client.trackException({ exception: e });
}
Other packages similar to applicationinsights
winston
Winston is a versatile logging library for Node.js. While it focuses more on logging rather than telemetry, it can be used to log events, errors, and other information. It does not provide the same level of built-in telemetry and performance monitoring as applicationinsights.
log4js
Log4js is another logging library for Node.js, inspired by the Java log4j library. It provides a variety of appenders for logging to different destinations. Like winston, it focuses on logging rather than telemetry and performance monitoring.
newrelic
New Relic is a comprehensive application performance monitoring tool that provides similar functionalities to applicationinsights, including telemetry, error tracking, and performance monitoring. It is a commercial product with a broader set of features and integrations.
datadog
Datadog is a monitoring and analytics platform for developers, IT operations teams, and business users. It offers extensive features for monitoring applications, including telemetry, performance metrics, and log management. It is a commercial product with a wide range of integrations and capabilities.
Application Insights for Node.js
This project provides a Node.js SDK for Application Insights. Application Insights is a service that allows developers to keep their applications available, performant, and successful. This node module will allow you to send telemetry of various kinds (event, trace, exception, etc.) to the Application Insights service where they can be visualized in the Azure Portal.
Requirements
Install
npm install applicationinsights
Get an instrumentation key
Note: an instrumentation key is required before any data can be sent. Please see the "Getting an Application Insights Instrumentation Key" section of the wiki for more information. To try the SDK without an instrumentation key, set the instrumentationKey config value to a non-empty string.
Usage
This will enable request monitoring, unhandled exception tracking, and system performance monitoring (CPU/Memory/RPS)
import appInsights = require("applicationinsights");
appInsights.setup("<instrumentation_key>").start();
The instrumentation key can also be set in the environment variable APPINSIGHTS_INSTRUMENTATIONKEY. If this is done, no argument is required when calling appInsights.setup()
or appInsights.getClient()
.
Customized Usage
#####Disabling auto-collection#####
import appInsights = require("applicationinsights");
appInsights.setup("<instrumentation_key>")
.setAutoCollectRequests(false)
.setAutoCollectPerformance(false)
.setAutoCollectExceptions(false)
.start();
#####Using multiple instrumentaion keys#####
import appInsights = require("applicationinsights");
appInsights.setup("<instrumentation_key>").start();
var otherClient = appInsights.getClient("<other_instrumentation_key>");
otherClient.trackEvent("custom event");
#####Custom monitoring#####
import appInsights = require("applicationinsights");
var client = appInsights.getClient();
client.trackEvent("custom event", {customProperty: "custom property value"});
client.trackException(new Error("handled exceptions can be logged with this method"));
client.trackMetric("custom metric", 3);
client.trackTrace("trace message");
#####Example with tracking dependency#####
import appInsights = require("applicationinsights");
var client = appInsights.getClient();
var startTime = Date.now();
var endTime = Date.now();
var elapsedTime = endTime - startTime;
var success = true;
client.trackDependency("dependency name", "command name", elapsedTime, success);
#####Example with manual request tracking of all "GET" requests#####
var http = require("http");
var appInsights = require("applicationinsights");
appInsights.setup("<instrumentation_key>")
.setAutoCollectRequests(false)
.start();
appInsights.client.commonProperties = {
environment: process.env.SOME_ENV_VARIABLE
};
appInsights.client.trackEvent("server start");
var port = process.env.port || 1337
var server = http.createServer(function (req, res) {
if(req.method === "GET") {
appInsights.client.trackRequest(req, res);
}
res.writeHead(200, { "Content-Type": "text/plain" });
res.end("Hello World\n");
}).listen(port);
var start = +new Date;
server.on("listening", () => {
var end = +new Date;
var duration = end - start;
appInsights.client.trackMetric("StartupTime", duration);
});
Contributing
Development environment