Add wrangler logs command to search past logs. Let LLMs & agents read logs more easily

[remorses]

Describe the solution

With the new observability features it should be possible to implement a command that gets the last worker logs without using tail

This would be super useful for agents to let them see the logs inside the worker after a request

The API call would look something like this

ACCOUNT_ID=$(jq -r .account_id wrangler.toml)

QUERY="fields * \
  | filter timestamp >= \"$START\" and timestamp < \"$END\" \
  | sort timestamp asc \
  | limit 1000"

wrangler api accounts/$ACCOUNT_ID/workers/observability/telemetry/query \
  --method POST \
  --body "{\"query\": \"$QUERY\"}"

[connorads]

This would be handy to allow coding agents to query logs without using the above workaround or the Cloudflare Observability MCP Server

[seeARMS]

my workaround. run with ./get-logs.mjs <request_id>

to paste into LLMs, run with ./get-logs.mjs <request_id> --json | pbcopy

#!/usr/bin/env node
/**
 * Fetch all Cloudflare Worker logs for a given request ID
 *
 * Usage: ./scripts/get-logs.mjs <request-id> [--hours=N] [--json]
 *
 * Environment variables required:
 *   CLOUDFLARE_API_TOKEN - API token with Workers:Read permission
 *   CLOUDFLARE_ACCOUNT_ID - Your Cloudflare account ID
 *
 * Examples:
 *   ./scripts/get-logs.mjs 9b9b9937bc6dc65e
 *   ./scripts/get-logs.mjs 9b9b9937bc6dc65e --hours=24
 *   ./scripts/get-logs.mjs 9b9b9937bc6dc65e --json
 */

const ACCOUNT_ID = process.env.CLOUDFLARE_ACCOUNT_ID
const API_TOKEN = process.env.CLOUDFLARE_API_TOKEN

const args = process.argv.slice(2);
const requestId = args.find((arg) => !arg.startsWith('--'));
const hoursArg = args.find((arg) => arg.startsWith('--hours='));
const hours = hoursArg ? parseInt(hoursArg.split('=')[1], 10) : 168; // Default 7 days (max retention)
const jsonOutput = args.includes('--json');

if (!requestId) {
	console.error('Usage: get-logs.mjs <request-id> [--hours=N] [--json]');
	console.error('');
	console.error('Options:');
	console.error('  --hours=N   Look back N hours (default: 168, max 7 days)');
	console.error('  --json      Output raw JSON instead of formatted logs');
	console.error('');
	console.error('Environment variables:');
	console.error('  CLOUDFLARE_API_TOKEN   - API token with Workers:Read permission');
	console.error('  CLOUDFLARE_ACCOUNT_ID  - Your Cloudflare account ID');
	process.exit(1);
}

if (!ACCOUNT_ID || !API_TOKEN) {
	console.error('Error: Missing required environment variables');
	console.error('  CLOUDFLARE_ACCOUNT_ID:', ACCOUNT_ID ? 'set' : 'missing');
	console.error('  CLOUDFLARE_API_TOKEN:', API_TOKEN ? 'set' : 'missing');
	process.exit(1);
}

const colors = {
	reset: '\x1b[0m',
	dim: '\x1b[2m',
	red: '\x1b[31m',
	yellow: '\x1b[33m',
	blue: '\x1b[34m',
	magenta: '\x1b[35m',
	cyan: '\x1b[36m',
	gray: '\x1b[90m',
};

const useColor = process.stdout.isTTY && !process.env.NO_COLOR;

function colorize(text, color) {
	return useColor ? `${color}${text}${colors.reset}` : text;
}

function levelColor(level) {
	switch (level?.toLowerCase()) {
		case 'error':
			return colors.red;
		case 'warn':
			return colors.yellow;
		case 'info':
			return colors.blue;
		case 'debug':
			return colors.gray;
		default:
			return colors.cyan;
	}
}

function formatTimestamp(ts) {
	if (!ts) return '';
	const date = new Date(ts);
	return date.toISOString().replace('T', ' ').replace('Z', '');
}

function truncate(str, maxLen = 200) {
	if (!str || str.length <= maxLen) return str;
	return str.slice(0, maxLen - 3) + '...';
}

function formatLogEntry(entry) {
	const meta = entry.$metadata || {};
	const workers = entry.$workers || {};

	const timestamp = formatTimestamp(entry.timestamp);
	const level = (meta.level || 'log').toUpperCase().padEnd(5);
	const service = meta.service || workers.scriptName || '';
	const message = meta.message || '';

	const parts = [
		colorize(timestamp, colors.dim),
		colorize(level, levelColor(meta.level)),
		service ? colorize(`[${service}]`, colors.magenta) : '',
		message,
	].filter(Boolean);

	let output = parts.join(' ');

	// Add context info if present
	const contextKeys = Object.keys(entry).filter(
		(k) => !['$metadata', '$workers', 'dataset', 'timestamp', 'source'].includes(k),
	);
	if (contextKeys.length > 0) {
		const context = contextKeys
			.map((k) => {
				const val = entry[k];
				if (typeof val === 'object') {
					return `${k}=${truncate(JSON.stringify(val), 100)}`;
				}
				return `${k}=${truncate(String(val), 100)}`;
			})
			.join(' ');
		if (context) {
			output += ` ${colorize('|', colors.gray)} ${colorize(context, colors.gray)}`;
		}
	}

	return output;
}

async function fetchLogs(requestId, hours) {
	const now = new Date();
	const from = new Date(now.getTime() - hours * 60 * 60 * 1000);

	const query = {
		view: 'events',
		queryId: `logs-${requestId}`,
		limit: 1000,
		parameters: {
			filters: [
				{
					key: '$metadata.requestId',
					operation: 'eq',
					type: 'string',
					value: requestId,
				},
			],
		},
		timeframe: {
			from: from.getTime(),
			to: now.getTime(),
		},
	};

	const url = `https://api.cloudflare.com/client/v4/accounts/${ACCOUNT_ID}/workers/observability/telemetry/query`;

	const response = await fetch(url, {
		method: 'POST',
		headers: {
			Authorization: `Bearer ${API_TOKEN}`,
			'Content-Type': 'application/json',
		},
		body: JSON.stringify(query),
	});

	if (!response.ok) {
		const text = await response.text();
		throw new Error(`API request failed: ${response.status} ${response.statusText}\n${text}`);
	}

	const data = await response.json();

	if (!data.success) {
		throw new Error(`API error: ${JSON.stringify(data.errors)}`);
	}

	// API returns { result: { events: { events: [...] } } }
	return data.result?.events?.events || [];
}

async function main() {
	try {
		console.error(
			colorize(`Fetching logs for request ID: ${requestId} (last ${hours} hours)...`, colors.dim),
		);

		const logs = await fetchLogs(requestId, hours);

		if (logs.length === 0) {
			console.error(colorize('No logs found for this request ID', colors.yellow));
			process.exit(0);
		}

		// Sort by timestamp ascending
		logs.sort((a, b) => (a.timestamp || 0) - (b.timestamp || 0));

		console.error(colorize(`Found ${logs.length} log entries\n`, colors.dim));

		if (jsonOutput) {
			console.log(JSON.stringify(logs, null, 2));
		} else {
			for (const entry of logs) {
				console.log(formatLogEntry(entry));
			}
		}

		// Print summary
		const meta = logs[0]?.$metadata || {};
		const workers = logs[0]?.$workers || {};
		console.error('');
		console.error(colorize('--- Summary ---', colors.dim));
		console.error(
			colorize(`  Service: ${meta.service || workers.scriptName || 'unknown'}`, colors.dim),
		);
		console.error(colorize(`  Trigger: ${meta.trigger || 'unknown'}`, colors.dim));
		console.error(colorize(`  Entries: ${logs.length}`, colors.dim));
		if (workers.outcome) {
			console.error(colorize(`  Outcome: ${workers.outcome}`, colors.dim));
		}
	} catch (error) {
		console.error(colorize(`Error: ${error.message}`, colors.red));
		process.exit(1);
	}
}

main();

[kevinsimper]

I struggled a lot and codex was never really able to read worker logs, so I made a solution now so AI can help fix bugs in production

https://github.com/kevinsimper/cf-worker-logs