feat: Add central error handler

Added: - Added Midleware to capture and handle all errors - will catch error from `throw ...` and `next(...)` - Added RequestError base error class to build consistent error objects - Added common errors like `UnauthorizedRequestError`, `BadRequestError` - Added consistent Logging solution using `winston` - Supports Loki Transporter using `winston-loki` - Outputing Legal disclaimer to console when `TELEMETRY_ENABLED=true` Changed: - Changed console.log to getLogger() favor of using consistent logging
2026-10-14 10:29:52 +00:00 · 2022-12-22 00:55:41 +01:00
parent 2d3255edc0
commit bd9041a62c
12 changed files with 688 additions and 11081 deletions
@@ -0,0 +1,64 @@
+import RequestError, { LogLevel, RequestErrorContext } from "./requestError"
+
+export const RouteNotFoundError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.INFO,
+    statusCode: error?.statusCode ?? 404,
+    type: error?.type ?? 'route_not_found',
+    message: error?.message ?? 'The requested source was not found',
+    context: error?.context,
+    stack: error?.stack
+})
+
+export const MethodNotAllowedError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.INFO,
+    statusCode: error?.statusCode ?? 405,
+    type: error?.type ?? 'method_not_allowed',
+    message: error?.message ?? 'The requested method is not allowed for the resource',
+    context: error?.context,
+    stack: error?.stack
+})
+
+export const UnauthorizedRequestError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.INFO,
+    statusCode: error?.statusCode ?? 401,
+    type: error?.type ?? 'unauthorized',
+    message: error?.message ?? 'You are not authorized to access this resource',
+    context: error?.context,
+    stack: error?.stack
+})
+  
+export const ForbiddenRequestError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.INFO,
+    statusCode: error?.statusCode ?? 403,
+    type: error?.type ?? 'forbidden',
+    message: error?.message ?? 'You are not allowed to access this resource',
+    context: error?.context,
+    stack: error?.stack
+})
+
+export const BadRequestError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.INFO,
+    statusCode: error?.statusCode ?? 400,
+    type: error?.type ?? 'bad_request',
+    message: error?.message ?? 'The request is invalid or cannot be served',
+    context: error?.context,
+    stack: error?.stack
+})
+
+export const InternalServerError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.ERROR,
+    statusCode: error?.statusCode ?? 500,
+    type: error?.type ?? 'internal_server_error',
+    message: error?.message ?? 'The server encountered an error while processing the request',
+    context: error?.context,
+    stack: error?.stack
+})
+
+export const ServiceUnavailableError = (error?: Partial<RequestErrorContext>) => new RequestError({
+    logLevel: error?.logLevel ?? LogLevel.ERROR,
+    statusCode: error?.statusCode ?? 503,
+    type: error?.type ?? 'service_unavailable',
+    message: error?.message ?? 'The service is currently unavailable. Please try again later.',
+    context: error?.context,
+    stack: error?.stack
+})
@@ -0,0 +1,65 @@
+/* eslint-disable no-console */
+import { createLogger, format, transports } from 'winston';
+import LokiTransport from 'winston-loki';
+import { LOKI_HOST, NODE_ENV } from '../config';
+
+const { combine, colorize, label, printf, splat, timestamp } = format;
+
+const logFormat = (prefix: string) => combine(
+  timestamp(),
+  splat(),
+  label({ label: prefix }),
+  printf((info) => `${info.timestamp} ${info.label} ${info.level}: ${info.message}`)
+);
+
+const createLoggerWithLabel = (level: string, label: string) => {
+  const _level = level.toLowerCase() || 'info'
+  //* Always add Console output to transports
+  const _transports: any[] = [
+    new transports.Console({
+      format: combine(
+        colorize(),
+        logFormat(label),
+        // format.json()
+      )
+    })
+  ]
+  //* Add LokiTransport if it's enabled
+  if(LOKI_HOST !== undefined){
+    _transports.push(
+      new LokiTransport({
+        host: LOKI_HOST,
+        handleExceptions: true,
+        handleRejections: true,
+        batching: true,
+        level: _level,
+        timeout: 30000,
+        format: format.combine(
+          format.json()
+        ),
+        labels: {app: process.env.npm_package_name, version: process.env.npm_package_version, environment: NODE_ENV},
+        onConnectionError: (err: Error)=> console.error('Connection error while connecting to Loki Server.\n', err)
+      })
+    )
+  }
+  
+  
+  return createLogger({
+    level: _level,
+    transports: _transports,
+    format: format.combine(
+      logFormat(label),
+      format.metadata({ fillExcept: ['message', 'level', 'timestamp', 'label'] })
+    )
+  });
+}
+
+const DEFAULT_LOGGERS = {
+  "backend-main": createLoggerWithLabel('info', '[IFSC:backend-main]'),
+  "database": createLoggerWithLabel('info', '[IFSC:database]'),
+}
+type LoggerNames = keyof typeof DEFAULT_LOGGERS
+
+export const getLogger = (loggerName: LoggerNames) => {
+  return DEFAULT_LOGGERS[loggerName]
+} 
@@ -0,0 +1,113 @@
+import { Request } from 'express'
+import { VERBOSE_ERROR_OUTPUT } from '../config'
+
+export enum LogLevel {
+    DEBUG = 100,
+    INFO = 200,
+    NOTICE = 250,
+    WARNING = 300,
+    ERROR = 400,
+    CRITICAL = 500,
+    ALERT = 550,
+    EMERGENCY = 600,
+}
+
+export type RequestErrorContext =  {
+	logLevel?: LogLevel,
+	statusCode: number,
+	type: string,
+	message: string,
+	context?: Record<string, unknown>,
+	stack?: string|undefined
+}
+
+export default class RequestError extends Error{
+
+    private _logLevel: LogLevel
+    private _logName: string
+    statusCode: number
+    type: string
+    context: Record<string, unknown>
+    extra: Record<string, string|number|symbol>[]
+    private stacktrace: string|undefined|string[]
+
+    constructor(
+        {logLevel, statusCode, type, message, context, stack} : RequestErrorContext
+        ){
+        super(message)
+        this._logLevel = logLevel || LogLevel.INFO
+        this._logName = LogLevel[this._logLevel]
+        this.statusCode = statusCode
+        this.type = type
+        this.context = context || {}
+        this.extra = []
+
+        if(stack) this.stack = stack
+        else Error.captureStackTrace(this, this.constructor)
+        this.stacktrace = this.stack?.split('\n')
+    }
+
+    static convertFrom(error: Error) {
+        //This error was not handled by error handler. Please report this incident to the staff.
+        return new RequestError({
+            logLevel: LogLevel.ERROR,
+            statusCode: 500,
+            type: 'internal_server_error',
+            message: 'This error was not handled by error handler. Please report this incident to the staff',
+            context: {
+                message: error.message,
+                name: error.name
+            },
+            stack: error.stack
+        })
+    }
+
+    get level(){ return this._logLevel }
+    get levelName(){ return this._logName }
+
+    withTags(...tags: string[]|number[]){
+        this.context['tags'] = Object.assign(tags, this.context['tags'])
+        return this
+    }
+
+    withExtras(...extras: Record<string, string|boolean|number>[]){
+        this.extra = Object.assign(extras, this.extra)
+        return this
+    }
+
+    private _omit(obj: any, keys: string[]): typeof obj{
+        const exclude = new Set(keys)
+        obj = Object.fromEntries(Object.entries(obj).filter(e => !exclude.has(e[0])))
+        return obj
+    }
+
+    public format(req: Request){
+        let _context = Object.assign({
+            stacktrace: this.stacktrace
+        }, this.context)
+
+        //* Omit sensitive information from context that can leak internal workings of this program if user is not developer
+        if(!VERBOSE_ERROR_OUTPUT){
+            _context = this._omit(_context, [
+                'stacktrace',
+                'exception',
+            ])
+        }
+
+        const formatObject = {
+            type: this.type,
+            message: this.message,
+            context: _context,
+            level: this.level,
+            level_name: this.levelName,
+            status_code: this.statusCode,
+            datetime_iso: new Date().toISOString(),
+            application: process.env.npm_package_name || 'unknown',
+            request_id: req.headers["Request-Id"],
+            extra: this.extra
+        }
+
+        return formatObject
+
+    }
+}