Next.js edge logging with Pino/Datadog

Posted on in Web

I encountered an issue with the potent combo of: Next.js App Router, Edge runtime, Server Actions, Pino and Datadog. After much googling, I couldn’t find a solution to this problem, hence this keyword-stuffed blog post for future me/others.

First up: logs were appearing in Datadog over multiple lines, which broke the stdout formatting rendering the logs unusable. Note, this only happened with the Edge runtime, not the standard Node variation. To solve this, I added a new section to the standard pino config:

const isServer = typeof window === 'undefined';
const isNextEdgeRuntime = process.env.NEXT_RUNTIME === 'edge';

export const config = {	
    // ...standard pino config
    ...(isServer && isNextEdgeRuntime && {
        browser: {
            write: {
                critical: (o: Object) => console.error(JSON.stringify(o)),
                debug: (o: Object) => console.log(JSON.stringify(o)),
                error: (o: Object) => console.error(JSON.stringify(o)),
                fatal: (o: Object) => console.error(JSON.stringify(o)),
                info: (o: Object) => console.log(JSON.stringify(o)),
                trace: (o: Object) => console.log(JSON.stringify(o)),
                warn: (o: Object) => console.warn(JSON.stringify(o)),
            },
        },
    }),
};

const loggerInstance = pino(config);

However, this created a second problem. Despite using console.error, errors were still being reported to Datadog as info, which then failed to trigger alerts and monitors. Not great. The solution was to pass a level parameter into the object; pre-stringification, on the warn and error methods.

const isServer = typeof window === 'undefined';
const isNextEdgeRuntime = process.env.NEXT_RUNTIME === 'edge';

export const config = {	
    // ...standard pino config
    ...(isServer && isNextEdgeRuntime && {
        browser: {
            write: {
                critical: (o: Object) => console.error(JSON.stringify(o)),
                debug: (o: Object) => console.log(JSON.stringify(o)),
                error: (o: Object) => console.error(JSON.stringify({ ...o, level: 'error' })),
                fatal: (o: Object) => console.error(JSON.stringify(o)),
                info: (o: Object) => console.log(JSON.stringify(o)),
                trace: (o: Object) => console.log(JSON.stringify(o)),
                warn: (o: Object) => console.warn(JSON.stringify({ ...o, level: 'warn' })),
            },
        },
    }),
};

const loggerInstance = pino(config);

This tells Datadog to treat the offending logs as errors/warnings, which can then be used to trigger alerts etc.

Posted on in Web