Working with Logging

Use structured logging with Pino throughout your application. Covers log levels, context, and workflow-safe logging patterns.

Implement Working with Logging

Use structured logging with Pino throughout your application. Covers log levels, context, and workflow-safe logging patterns.

See:

• Resource: using-logging in Fullstack Recipes

• URL: https://fullstackrecipes.com/recipes/using-logging

Basic Logging

Import the logger and use it throughout your application:

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

// Info level for normal operations logger.info("Server started", { port: 3000 });

// Warn level for recoverable issues logger.warn("Rate limit reached", { endpoint: "/api/chat" });

// Error level with Error objects logger.error(err, "Failed to process request");

// Debug level for development troubleshooting logger.debug("Cache miss", { key: "user:123" });

Structured Logging

Always include context as the first argument for structured logs:

// Context object first, message second logger.info({ userId: "123", action: "login" }, "User logged in");

// For errors, pass the error first logger.error({ err, userId: "123", endpoint: "/api/chat" }, "Request failed");

Log Levels

Use appropriate levels for different scenarios:

| 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 |

Configuring Log Level

Set the LOG_LEVEL environment variable:

Show all logs including debug

LOG_LEVEL="debug"

Production: only warnings and errors

LOG_LEVEL="warn"

Default is info if not set. Valid values: trace , debug , info , warn , error , fatal .

Logging in API Routes

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 });

} }

Logging in Workflows

Workflow functions run in a restricted environment. Use the logger step wrapper:

// 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 { loggerlevel; } }

Then use it in workflows:

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

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

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

References

• Pino Documentation

• Pino Log Levels