@logbrew/nestjs

NestJS interceptor helpers for the public LogBrew JavaScript SDK.

This package is intentionally thin. It adds NestJS HTTP interceptor UX while keeping event validation, retry, flush, and shutdown behavior in @logbrew/sdk.

Install

npm install @logbrew/sdk @logbrew/nestjs @nestjs/common @nestjs/core @nestjs/platform-express reflect-metadata rxjs
pnpm add @logbrew/sdk @logbrew/nestjs @nestjs/common @nestjs/core @nestjs/platform-express reflect-metadata rxjs

Global Interceptor

import { NestFactory } from "@nestjs/core";
import { RecordingTransport } from "@logbrew/sdk";
import { LogBrewInterceptor } from "@logbrew/nestjs";
import { AppModule } from "./app.module";

const app = await NestFactory.create(AppModule);

app.useGlobalInterceptors(new LogBrewInterceptor({
  serverApiKey: "LOGBREW_SERVER_API_KEY",
  spanIdFactory: () => "b7ad6b7169203331",
  transport: RecordingTransport.alwaysAccept()
}));

await app.listen(3000);

Inside a controller, the Express request object exposes request.logbrew:

import { Controller, Get, Req } from "@nestjs/common";
import type { Request } from "express";

@Controller()
export class AppController {
  @Get("/health")
  health(@Req() request: Request) {
    request.logbrew?.client.log("evt_log_001", "2026-06-02T10:00:03Z", {
      message: "health check reached",
      level: "info",
      logger: "nestjs"
    });
    return { ok: true };
  }
}

The interceptor uses Nest's HTTP ExecutionContext, adds request.logbrew before the route handler runs, captures successful request completion, and captures thrown route errors with RxJS catchError before rethrowing them to Nest's normal exception handling path.

Use serverApiKey directly for local server examples, or set LOGBREW_SERVER_API_KEY in your server environment and omit it. apiKey and LOGBREW_API_KEY are still accepted for compatibility with the lower-level JavaScript SDK.

When an incoming HTTP request has a valid W3C traceparent header, default request capture records the request as a LogBrew span that continues the incoming trace. Requests without traceparent, or with a malformed header, fall back to the existing request log event so bad client headers do not break the controller. Automatic request metadata uses the path without query text by default. Use captureRequests: false when a controller should only flush manual events, and use spanIdFactory when your runtime needs app-provided child span IDs.

Request Duration Metrics

Enable request metrics when you want low-cardinality latency histograms from NestJS routes without changing controller behavior:

app.useGlobalInterceptors(new LogBrewInterceptor({
  serverApiKey: "LOGBREW_SERVER_API_KEY",
  captureRequestMetrics: true
}));

This emits an explicit http.server.duration histogram with primitive metadata for framework, method, routeTemplate, statusCode, and statusCodeClass. Route templates are preferred when Nest exposes them through the underlying HTTP adapter, and query strings or hashes are omitted by default. Use captureRequests: false with captureRequestMetrics: true when you only want request metrics.

Packaged Examples

The package includes example source for the interceptor, controller access, and app-owned response handling. Use the snippets above as the starting point for wiring LogBrew into your NestJS application.