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-loggingin 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 {
logger[level](message);
}
}Then use it in workflows:
import { log } from "./steps/logger";
export async function chatWorkflow({ chatId }) {
"use workflow";
await log("info", "Workflow started", { chatId });
}