transport.ts

import { Transform } from 'stream';
import { spawn } from 'child_process';

import build from 'pino-abstract-transport';

export interface Options {
  logLevel: string;
}

export default function transport({ logLevel }: Options) {
  const logScript = `$Input | ForEach-Object {
    $data = ($_ | ConvertFrom-Json)
    $message = @{
      Data = $data;
      LogLevel = '${logLevel}';
      Message = $data.msg
    }

    $dataTime = New-Object -Type DateTime -ArgumentList 1970, 1, 1, 0, 0, 0, 0
    $dataTime = [DateTime]::SpecifyKind($dataTime, [System.DateTimeKind]::Utc)
    $dataTime = $dataTime.AddMilliseconds($data.time)
    $message.DataTime = $dataTime.ToString('u')

    $msg = ($message | ConvertTo-Json -Compress)

    if ($data.level -lt 30) {
      $message.Severity = "Normal"
      Write-Verbose $msg
    } elseif ($data.level -lt 40) {
      $message.Severity = "Warning"
      Write-Warning $msg
    } else {
      $message.Severity = "Error"
      Write-Error $msg
    }
  }
  `;

  const proc = spawn('pwsh', [
    '-NoProfile',
    '-NonInteractive',
    '-c',
    logScript,
  ]);
  proc.stdout.pipe(process.stdout);
  proc.stderr.pipe(process.stderr);

  return build(async (source) => {
    source
      .pipe(
        new Transform({
          objectMode: true,
          autoDestroy: true,
          transform(chunk, _encoding, callback) {
            callback(null, JSON.stringify(chunk) + '\n');
          },
        }),
      )
      .pipe(proc.stdin);
  });
}