logging-best-practices

Logging Best Practices

Emit structured logs with Pino throughout the app.

Prerequisites

Complete these setup recipes first:

• Pino Logging Setup

Logging

Import logger from @/lib/logging/logger. Pass a context object first, message second. For errors, put err in the context object.

import { logger } from "@/lib/logging/logger";

logger.info({ port: 3000 }, "Server started");
logger.warn({ endpoint: "/api/chat" }, "Rate limit reached");
logger.debug({ key: "user:123" }, "Cache miss");
logger.error({ err, userId: "123", endpoint: "/api/chat" }, "Request failed");

Levels

Level	When to Use
trace	Detailed debugging (rarely used)
debug	Development troubleshooting
info	Normal operations, business events
warn	Recoverable issues, deprecation warnings
error	Failures that need attention
fatal	Critical failures, app cannot continue

Set the active threshold via LOG_LEVEL (defaults to info). Use warn in production.

LOG_LEVEL="debug"

In API Routes

Log on the way out with timing context.

import { logger } from "@/lib/logging/logger";

export async function POST(request: Request) {
  const start = Date.now();
  try {
    const result = await processRequest(request);
    logger.info(
      { duration: Date.now() - start, status: 200 },
      "Request completed",
    );
    return Response.json(result);
  } catch (err) {
    logger.error({ err, duration: Date.now() - start }, "Request failed");
    return Response.json({ error: "Internal error" }, { status: 500 });
  }
}

In Workflows

The workflow runtime can't import Node modules, so the logger can't be called directly. Wrap it in a "use step" function.

// src/workflows/chat/steps/logger.ts
import { logger } from "@/lib/logging/logger";

export async function log(
  level: "info" | "warn" | "error" | "debug",
  message: string,
  data?: Record<string, unknown>,
): Promise<void> {
  "use step";

  if (data) {
    logger[level](data, message);
  } else {
    logger[level](message);
  }
}

import { log } from "./steps/logger";

export async function chatWorkflow({ chatId }) {
  "use workflow";

  await log("info", "Workflow started", { chatId });
}

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References

• Pino Documentation
• Pino Log Levels