winston-transport-logtail/src/winston.ts

logtail.com transport for winston v3 logger

import { LogEntry } from "winston";
import Transport from "winston-transport";

import { Logtail } from "@logtail/node";
import { LogLevel } from "@logtail/types";

import { getStackContext } from "./context";

export class LogtailTransport extends Transport {
  private _context: any;

  public constructor(private _logtail: Logtail, stackContext?: any) {
    super();
    this._context = stackContext;
  }

  // Allow stack context to be parsed from a different StackFrame.
  public setStackContext(_context: any) {
    this._context = _context;
  }

  public log(info: LogEntry, cb: Function) {
    // Pass the log to Winston's internal event handlers
    setImmediate(() => {
      this.emit("logged", info);
    });

    const { level, message, ...meta } = info;

    // Determine the log level
    let logLevel: LogLevel;

    switch (level) {
      case "debug":
        logLevel = LogLevel.Debug;
        break;

      case "warn":
        logLevel = LogLevel.Warn;
        break;

      case "error":
        logLevel = LogLevel.Error;
        break;

      // All other log levels use `Info` by default
      default:
        logLevel = LogLevel.Info;
    }

    // Log out to Logtail
    void this._logtail.log(message, logLevel, {
      ...meta,
      ...getStackContext(this._context),
    });

    // Winston callback...
    cb();
  }
}