@shellicar/winston-azure-application-insights

Update

This has been forked as the original and other forks have not been updated in quite a while.

Most of this README has been left as is, with relevant updates only.

Intro

An Azure Application Insights transport for Winston logging library.

This transport is designed to make it easy to obtain a reference to a standard logging library that broadcasts to Application Insights.

Your logging interface can remain familiar to standard (logger.info, logger.error etc) without intertwining any Azure-specific implementation detail.

Read the project changelog

Installation

pnpm install @shellicar/winston-azure-application-insights

Support

This library has CJS and ESM outputs.

Continuous integration tests are run against the NodeJS LTS versions.

Usage

See demo.ts and the examples directory for a usage examples.

Connection String

Note: an connection string is required before any data can be sent. Please see the "Connection Strings in Application Insights" for more information.

The connection string can be supplied:

• Passing an initialized Application Insights client in the "client" options property:

import { setup, defaultClient } from 'applicationinsights';
import { AzureApplicationInsightsLogger } from '@shellicar/winston-azure-application-insights';

setup().start();

const insightsLogger = new AzureApplicationInsightsLogger({
  client: defaultClient,
});

const { setup, defaultClient } = require("applicationinsights");
const { AzureApplicationInsightsLogger } = require('@shellicar/winston-azure-application-insights');

setup(process.env.APPLICATIONINSIGHTS_CONNECTION_STRING).start();

const insightsLogger = new AzureApplicationInsightsLogger({
  client: defaultClient,
});

I get an error when using this transport

If you receive the error:

No instrumentation key or connection string was provided to the Azure Monitor Exporter

Then you didn't specify a suitable instrumentation key. See the section above.

Error: @opentelemetry/api: Attempted duplicate registration of API: context

This may be because your environment has already (maybe implicitly) loaded applicationinsights and called .setup(). This happens if you are running an Azure Function App and have APPLICATIONINSIGHTS_CONNECTION_STRING set. The best solution to this is to load applicationinsights and pass in appInsights.defaultClient using the client option as per example.

I'm seeing multiple traces with similar/identical messages

applicationinsights deeply integrates into the console transports, and winston itself (via diagnostic-channel). If you are integrating this transport, it's recommended to disable diagnostic-channel and console auto collection:

To control diagnostic-channel, follow the guide in the main repository.

It is recommended to use only this transport where your application is running in production mode and needs to stream data to Application Insights. In all other scenarios such as local debug and test suites, the console transport (or similar) should suffice. This is to avoid polluting instances/unnecessary cost.

Despite this notice, to specifically disable console transport collection, use .setAutoCollectConsole(false):

setup().setAutoCollectConsole(false);

Options

• level: lowest logging level transport to be logged (default: info)
• sendErrorsAsExceptions: Boolean flag indicating whether to also track errors to the AI exceptions table. See section below for more details (default: true).

SDK integration options (required):

• client: An existing App Insights client

Log Levels

Supported log levels are:

Winston Level | App Insights level ---------------|------------------ error | error (3) warn | warning (2) info | informational (1) verbose | verbose (0) debug | verbose (0) silly | verbose (0)

All other possible levels, or custom levels, will default to info

Error & Exception Logging: Exceptions vs. Traces

The Application Insights "exceptions" table allows you to see more detailed error information including the stack trace. Therefore for all log events at severity level error or above, an exception is logged if the library detects that an Error object has been passed. The log event will still generate a trace with the correct severity level regardless of this setting, but please note that any Error object will have its stack property omitted when sent to trackTrace. All other properties are included.

This allows you to see clearly Azure Application Insights instead of having to access trace information manually and set up alerts based on the related metrics.

How it works with sendErrorsAsExceptions: true:

• logger.error('error message'); creates a trace with severity level 3; no exception is tracked
• logger.error(new Error('error message')); creates a trace with severity level 3, and an exception with the Error object as argument
• logger.error('error message', new Error('error message')); creates a trace with severity level 3, and an exception with the Error object as argument
• logger.error(new Error('error message'), logContext); creates a trace and exception and logContext is set to the customDimensions (properties) track* field
• logger.info(new Error('error message')); creates a trace with severity level 1; no exception is tracked

If you do not wish to track exceptions, you can set the option sendErrorsAsExceptions: false when configuring the transport.