azure-middy-logger

Logger middleware for the azure-middy framework, the Node.js middleware engine for Azure functions.

Install

To install the logger middleware, you can use NPM:

npm install --save @kevboutin/azure-middy-logger

Prerequisites

• Node.js >= 18
• An Azure Function App

Usage

The middleware provides logging capabilities for your Azure Functions using the azure-function-log-intercept library.

JavaScript (CommonJS)

const { app } = require("@azure/functions");
const middy = require("@kevboutin/azure-middy-core");
const loggerMiddleware = require("@kevboutin/azure-middy-logger");

// Your handler
const baseHandler = async (req, context) => {
    // Your business logic here
    // Logging is automatically handled by the middleware
    return {
        body: JSON.stringify({ message: "Success" }),
    };
};

// Wrap handler with middy
const handler = middy(baseHandler).use(loggerMiddleware());

module.exports = { handler };

app.http("yourFunction", {
    route: "your-route",
    methods: ["GET"],
    authLevel: "anonymous",
    handler: handler,
});

TypeScript

import { app } from "@azure/functions";
import middy from "@kevboutin/azure-middy-core";
import { loggerMiddleware } from "@kevboutin/azure-middy-logger";
import type {
    AzureFunctionContext,
    AzureFunctionRequest,
} from "@kevboutin/azure-middy-types";

// Your handler
const baseHandler = async (
    req: AzureFunctionRequest,
    context: AzureFunctionContext,
) => {
    // Your business logic here
    // Logging is automatically handled by the middleware

    context.log("Processing request");
    context.info("Request details:", {
        method: req["method"],
        url: req["url"],
    });

    return {
        body: JSON.stringify({ message: "Success" }),
    };
};

// Wrap handler with middy
const handler = middy(baseHandler).use(loggerMiddleware());

export { handler };

app.http("yourFunction", {
    route: "your-route",
    methods: ["GET"],
    authLevel: "anonymous",
    handler: handler,
});

TypeScript Support

This package includes full TypeScript support with:

• Type Definitions: Complete type definitions for all logging interfaces and functions
• Type Safety: Full type checking for request and context objects
• IntelliSense: Enhanced IDE support with autocomplete and type hints

Available Types

import { LoggerMiddleware } from "@kevboutin/azure-middy-logger";
import type {
    AzureFunctionContext,
    AzureFunctionRequest,
} from "@kevboutin/azure-middy-types";

TypeScript Configuration

To use TypeScript with this package, ensure your tsconfig.json includes:

{
    "compilerOptions": {
        "esModuleInterop": true,
        "moduleResolution": "node"
    }
}

How it works

The logger middleware uses the azure-function-log-intercept library to intercept and handle logging in your Azure Functions. It automatically:

1. Intercepts the Azure Function context
2. Handles log routing
3. Ensures proper log formatting
4. Maintains context across async operations

Documentation and examples

For more documentation and examples, refer to the main Azure-middy monorepo on GitHub.

Contributing

Everyone is very welcome to contribute to this repository. Feel free to raise issues or to submit Pull Requests.

License

Licensed under MIT License. Copyright (c) 2024 Kevin Boutin and the Azure-Middy team.