@logtape/file/dist/filesink.base.js

File sink and rotating file sink for LogTape

import { defaultTextFormatter } from "@logtape/logtape";

//#region filesink.base.ts
/**
* Get a platform-independent file sink.
*
* @typeParam TFile The type of the file descriptor.
* @param path A path to the file to write to.
* @param options The options for the sink and the file driver.
* @returns A sink that writes to the file.  The sink is also a disposable
*          object that closes the file when disposed.
*/
function getBaseFileSink(path, options) {
	const formatter = options.formatter ?? defaultTextFormatter;
	const encoder = options.encoder ?? new TextEncoder();
	const bufferSize = options.bufferSize ?? 1024 * 8;
	const flushInterval = options.flushInterval ?? 5e3;
	let fd = options.lazy ? null : options.openSync(path);
	let buffer = "";
	let lastFlushTimestamp = Date.now();
	function flushBuffer() {
		if (fd == null) return;
		if (buffer.length > 0) {
			options.writeSync(fd, encoder.encode(buffer));
			buffer = "";
			options.flushSync(fd);
			lastFlushTimestamp = Date.now();
		}
	}
	const sink = (record) => {
		if (fd == null) fd = options.openSync(path);
		buffer += formatter(record);
		const shouldFlushBySize = buffer.length >= bufferSize;
		const shouldFlushByTime = flushInterval > 0 && record.timestamp - lastFlushTimestamp >= flushInterval;
		if (shouldFlushBySize || shouldFlushByTime) flushBuffer();
	};
	sink[Symbol.dispose] = () => {
		if (fd !== null) {
			flushBuffer();
			options.closeSync(fd);
		}
	};
	return sink;
}
/**
* Get a platform-independent rotating file sink.
*
* This sink writes log records to a file, and rotates the file when it reaches
* the `maxSize`.  The rotated files are named with the original file name
* followed by a dot and a number, starting from 1.  The number is incremented
* for each rotation, and the maximum number of files to keep is `maxFiles`.
*
* @param path A path to the file to write to.
* @param options The options for the sink and the file driver.
* @returns A sink that writes to the file.  The sink is also a disposable
*          object that closes the file when disposed.
*/
function getBaseRotatingFileSink(path, options) {
	const formatter = options.formatter ?? defaultTextFormatter;
	const encoder = options.encoder ?? new TextEncoder();
	const maxSize = options.maxSize ?? 1024 * 1024;
	const maxFiles = options.maxFiles ?? 5;
	const bufferSize = options.bufferSize ?? 1024 * 8;
	const flushInterval = options.flushInterval ?? 5e3;
	let offset = 0;
	try {
		const stat = options.statSync(path);
		offset = stat.size;
	} catch {}
	let fd = options.openSync(path);
	let lastFlushTimestamp = Date.now();
	function shouldRollover(bytes) {
		return offset + bytes.length > maxSize;
	}
	function performRollover() {
		options.closeSync(fd);
		for (let i = maxFiles - 1; i > 0; i--) {
			const oldPath = `${path}.${i}`;
			const newPath = `${path}.${i + 1}`;
			try {
				options.renameSync(oldPath, newPath);
			} catch (_) {}
		}
		options.renameSync(path, `${path}.1`);
		offset = 0;
		fd = options.openSync(path);
	}
	function flushBuffer() {
		if (buffer.length > 0) {
			const bytes = encoder.encode(buffer);
			buffer = "";
			if (shouldRollover(bytes)) performRollover();
			options.writeSync(fd, bytes);
			options.flushSync(fd);
			offset += bytes.length;
			lastFlushTimestamp = Date.now();
		}
	}
	let buffer = "";
	const sink = (record) => {
		buffer += formatter(record);
		const shouldFlushBySize = buffer.length >= bufferSize;
		const shouldFlushByTime = flushInterval > 0 && record.timestamp - lastFlushTimestamp >= flushInterval;
		if (shouldFlushBySize || shouldFlushByTime) flushBuffer();
	};
	sink[Symbol.dispose] = () => {
		flushBuffer();
		options.closeSync(fd);
	};
	return sink;
}

//#endregion
export { getBaseFileSink, getBaseRotatingFileSink };
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