Utils Abstractions

A collection of utilities and abstractions for logging, middlewares, etc.

API Documentation

Logger

BaseLogger

Defines the logger's structure.

interface BaseLogger {
    info(message: string, meta?: any): void
    debug(message: string, meta?: any): void
    error(message: string, meta?: any): void
    warn(message: string, meta?: any): void
    http(message: string, meta?: any): void
}

BaseMetadataFields

Defines the fields for the metadata of logging. All the new definitions must extend from this interface.

interface BaseMetadataFields extends Record<string, string | number | unknown> {
    domain?: string
    layer?: 'Application' | 'Infrastructure' | 'Presentation' | 'None' | string
    context?: string
}

Log message structure

The structure of the log messages is the next:

[2023-03-30 12:16:16.0761 PM] [log-level] [domain.layer.context]: Database connected

These fields are based in the concepts of Clean Architecture. For an initial approach domain can be similar to a module or submodule.

LoggerContainer

Stores implementations of BaseLogger.

Because you can have different logging mechanisms (console, files, stream, etc.) this container keeps all the defined implementations and allows you, either all or one definition depending on the needed context.

Each implementation is mapped to a name, this allows you to select an instance to use. In the case we want to use all the registered implementations you can use the log level method that you need.

Also, it is configured to be used as dependency with Inversify.

class LoggerContainer implements BaseLogger {...}

Errors

• LoggerAlreadyRegisteredError
• LoggerNotExists

Example

// Register a new logger, in case there already exists throws an error
loggerContainer.addLogger('winston-console', new WinstonLogger())

// Get an instancia, in case there is no exists throws an error
const logger = loggerContainer.getLogger('winston-console')

logger.debug('Hello ..')

// Delete an instance, in case there is no exists throws an error
loggerContainer.removeLogger('winston-console')

// Use all registered loggers
loggerContainer.info('Logging for all')

Logger Implementations

• WinstonLogger: Using winston.
• SeqLogger: Using datalust/winston-seq.
  • Depends on SEQ_SERVER and SEQ_TOKEN.
• LokiLogger: Using winston-loki.
  • Depends on LOKI_SERVER, LOKI_INTERVAL and LOKI_APP_LABEL env.
  • In case that LOKI_APP_LABEL is not assigned the default value is logger-container.

getRequestData

Adds information about the request in the metadata. Sets the fields:

• url
• method

reassign: If true assigns the values in the object directly instead of create a copy. Default to false.

function getRequestData(metadata: BaseMetadataFields, reassign?: boolean): BaseMetadataFields

showDebugQuery

Add the query to the logs. Depends on the env SHOW_QUERY with the value show.

function showDebugQuery(message: string, query: string): string

---

CORS

corsOptions

Defines a configuration for allowed origins. The list of origins comes from then env CORS_ORIGINS in a single string separated by commas.

Example

const corsOptions: CorsOptions

// CORS_ORIGINS = https://dev.test.app,https://admin.test.app

credentialsHeader

Sets the header Access-Control-Allow-Credentials to the request based on the CORS_ORIGINS.

function credentialsHeader(req: Request, res: Response, next: NextFunction)

---

Middlewares

errorHandler

An express error middleware to handle error responses.

function errorHandler(err: any, req: Request, res: Response, next: NextFunction)

HelmetConfig

The Helmet middleware with custom options for:

• hidePoweredBy
• dnsPrefetchControl
• frameguard
• noSniff
• xssFilter

const HelmetConfig = helmet({ ... })

httpRequestData

Fetch data from the request and keep it in memory. Works together a logger, and it takes the values of:

• body
• params
• query
• headers
• url
• method

function httpRequestData(logger: BaseLogger): (req: Request, res: Response, next: NextFunction) => void

morganCustomLogger

A custom implementation of morgan for http request.

function morganCustomLogger(logger: BaseLogger): Handler<IncomingMessage, ServerResponse<IncomingMessage>>

Auth

JwtStrategyOptions

Default configurations for passport-jwt with:

• Extract token from Authorization Header (Bearer)
• Issuer
• Algorithms

Requires the env JWT_ACCESS_SECRET, JWT_ISSUER and JWT_ALGORITHM

const JWT_STRATEGY_OPTIONS: StrategyOptions