Function defaultHandler

defaultHandler(opts?: HandlerOpts): Handler
Creates a log handler from options and Nebius logging environment variables.

Explicit scalar options override their matching environment settings. Important settings include NEBIUS_LOG, NEBIUS_LOG_JSON, NEBIUS_LOG_ALWAYS_ADD_TRACE, and NEBIUS_LOG_OUTPUT.

Per-name variables add environment filters. The suffix is matched with a case-sensitive loggerName.includes(suffix) check. For example, NEBIUS_LOG_auth=DEBUG matches nebius.auth. If opts.filters is present, the environment filters are added to it; they are not replaced. A per-name filter cannot lower the handler's global minimum level. To emit debug records, also set NEBIUS_LOG=DEBUG or pass level: Level.DEBUG.

Without explicit output, NEBIUS_LOG_OUTPUT accepts stderr, stdout, console, none, or a file path. Color selection also follows NO_COLOR, FORCE_COLOR, and whether stderr is a terminal.
Parameters
- Optionalopts: HandlerOpts
Returns Handler
Example
```
import {
  defaultHandler,
  Level,
  Logger,
} from '@nebius/js-sdk/runtime/util/logging';

const handler = defaultHandler({
  level: Level.DEBUG,
  useJson: true,
  filters: ['nebius.auth', 'nebius.request'],
});
const logger = new Logger(handler, 'nebius.request');
```
- Defined in src/runtime/util/logging.ts:886