rotating-file-stream/dist/esm/index.js

Opens a stream.Writable to a file rotated by interval and/or size. A logrotate alternative.

import { exec } from "child_process";
import { createGzip } from "zlib";
import { Writable } from "stream";
import { access, constants, createReadStream, createWriteStream } from "fs";
import { mkdir, open, readFile, rename, stat, unlink, writeFile } from "fs/promises";
import { sep } from "path";
import { TextDecoder } from "util";
async function exists(filename) {
    return new Promise(resolve => access(filename, constants.F_OK, error => resolve(!error)));
}
export class RotatingFileStreamError extends Error {
    code = "RFS-TOO-MANY";
    constructor() {
        super("Too many destination file attempts");
    }
}
export class RotatingFileStream extends Writable {
    createGzip;
    exec;
    file;
    filename;
    finished;
    fsCreateReadStream;
    fsCreateWriteStream;
    fsOpen;
    fsReadFile;
    fsStat;
    fsUnlink;
    generator;
    initPromise;
    last;
    maxTimeout;
    next;
    options;
    prev;
    rotation;
    size;
    stdout;
    timeout;
    timeoutPromise;
    constructor(generator, options) {
        const { encoding, history, maxFiles, maxSize, path } = options;
        super({ decodeStrings: true, defaultEncoding: encoding });
        this.createGzip = createGzip;
        this.exec = exec;
        this.filename = path + generator(null);
        this.fsCreateReadStream = createReadStream;
        this.fsCreateWriteStream = createWriteStream;
        this.fsOpen = open;
        this.fsReadFile = readFile;
        this.fsStat = stat;
        this.fsUnlink = unlink;
        this.generator = generator;
        this.maxTimeout = 2147483640;
        this.options = options;
        this.stdout = process.stdout;
        if (maxFiles || maxSize)
            options.history = path + (history ? history : this.generator(null) + ".txt");
        this.on("close", () => (this.finished ? null : this.emit("finish")));
        this.on("finish", () => (this.finished = this.clear()));
        // In v15 was introduced the _constructor method to delay any _write(), _final() and _destroy() calls
        // Until v16 will be not deprecated we still need this.initPromise
        // https://nodejs.org/api/stream.html#stream_writable_construct_callback
        (async () => {
            try {
                this.initPromise = this.init();
                await this.initPromise;
                delete this.initPromise;
            }
            catch (e) { }
        })();
    }
    _destroy(error, callback) {
        this.refinal(error, callback);
    }
    _final(callback) {
        this.refinal(undefined, callback);
    }
    _write(chunk, encoding, callback) {
        this.rewrite([{ chunk, encoding }], 0, callback);
    }
    _writev(chunks, callback) {
        this.rewrite(chunks, 0, callback);
    }
    async refinal(error, callback) {
        try {
            this.clear();
            if (this.initPromise)
                await this.initPromise;
            if (this.timeoutPromise)
                await this.timeoutPromise;
            await this.reclose();
        }
        catch (e) {
            return callback(error || e);
        }
        callback(error);
    }
    async rewrite(chunks, index, callback) {
        const { size, teeToStdout } = this.options;
        try {
            if (this.initPromise)
                await this.initPromise;
            for (let i = 0; i < chunks.length; ++i) {
                const { chunk } = chunks[i];
                this.size += chunk.length;
                if (this.timeoutPromise)
                    await this.timeoutPromise;
                await this.file.write(chunk);
                if (teeToStdout && !this.stdout.destroyed)
                    this.stdout.write(chunk);
                if (size && this.size >= size)
                    await this.rotate();
            }
        }
        catch (e) {
            return callback(e);
        }
        callback();
    }
    async init() {
        const { immutable, initialRotation, interval, size } = this.options;
        // In v15 was introduced the _constructor method to delay any _write(), _final() and _destroy() calls
        // Once v16 will be deprecated we can restore only following line
        // if(immutable) return this.immutate(true);
        if (immutable)
            return new Promise((resolve, reject) => process.nextTick(() => this.immutate(true).then(resolve).catch(reject)));
        let stats;
        try {
            stats = await stat(this.filename);
        }
        catch (e) {
            if (e.code !== "ENOENT")
                throw e;
            return this.reopen(0);
        }
        if (!stats.isFile())
            throw new Error(`Can't write on: ${this.filename} (it is not a file)`);
        if (initialRotation) {
            this.intervalBounds(this.now());
            const prev = this.prev;
            this.intervalBounds(new Date(stats.mtime.getTime()));
            if (prev !== this.prev)
                return this.rotate();
        }
        this.size = stats.size;
        if (!size || stats.size < size)
            return this.reopen(stats.size);
        if (interval)
            this.intervalBounds(this.now());
        return this.rotate();
    }
    async makePath(name) {
        return mkdir(name.split(sep).slice(0, -1).join(sep), { recursive: true });
    }
    async reopen(size) {
        let file;
        try {
            file = await open(this.filename, "a", this.options.mode);
        }
        catch (e) {
            if (e.code !== "ENOENT")
                throw e;
            await this.makePath(this.filename);
            file = await open(this.filename, "a", this.options.mode);
        }
        this.file = file;
        this.size = size;
        this.interval();
        this.emit("open", this.filename);
    }
    async reclose() {
        const { file } = this;
        if (!file)
            return;
        delete this.file;
        return file.close();
    }
    now() {
        return new Date();
    }
    async rotate() {
        const { immutable, rotate } = this.options;
        this.size = 0;
        this.rotation = this.now();
        this.clear();
        this.emit("rotation");
        await this.reclose();
        if (rotate)
            return this.classical();
        if (immutable)
            return this.immutate(false);
        return this.move();
    }
    async findName() {
        const { interval, path, intervalBoundary } = this.options;
        for (let index = 1; index < 1000; ++index) {
            const filename = path + this.generator(interval && intervalBoundary ? new Date(this.prev) : this.rotation, index);
            if (!(await exists(filename)))
                return filename;
        }
        throw new RotatingFileStreamError();
    }
    async move() {
        const { compress } = this.options;
        const filename = await this.findName();
        await this.touch(filename);
        if (compress)
            await this.compress(filename);
        else
            await rename(this.filename, filename);
        return this.rotated(filename);
    }
    async touch(filename) {
        let file;
        try {
            file = await this.fsOpen(filename, "a");
        }
        catch (e) {
            if (e.code !== "ENOENT")
                throw e;
            await this.makePath(filename);
            file = await open(filename, "a");
        }
        await file.close();
        return this.unlink(filename);
    }
    async classical() {
        const { compress, path, rotate } = this.options;
        let rotatedName = "";
        for (let count = rotate; count > 0; --count) {
            const currName = path + this.generator(count);
            const prevName = count === 1 ? this.filename : path + this.generator(count - 1);
            if (!(await exists(prevName)))
                continue;
            if (!rotatedName)
                rotatedName = currName;
            if (count === 1 && compress)
                await this.compress(currName);
            else {
                try {
                    await rename(prevName, currName);
                }
                catch (e) {
                    if (e.code !== "ENOENT")
                        throw e;
                    await this.makePath(currName);
                    await rename(prevName, currName);
                }
            }
        }
        return this.rotated(rotatedName);
    }
    clear() {
        if (this.timeout) {
            clearTimeout(this.timeout);
            this.timeout = null;
        }
        return true;
    }
    intervalBoundsBig(now) {
        const year = this.options.intervalUTC ? now.getUTCFullYear() : now.getFullYear();
        let month = this.options.intervalUTC ? now.getUTCMonth() : now.getMonth();
        let day = this.options.intervalUTC ? now.getUTCDate() : now.getDate();
        let hours = this.options.intervalUTC ? now.getUTCHours() : now.getHours();
        const { num, unit } = this.options.interval;
        if (unit === "M") {
            day = 1;
            hours = 0;
        }
        else if (unit === "d")
            hours = 0;
        else
            hours = parseInt((hours / num), 10) * num;
        this.prev = new Date(year, month, day, hours, 0, 0, 0).getTime();
        if (unit === "M")
            month += num;
        else if (unit === "d")
            day += num;
        else
            hours += num;
        this.next = new Date(year, month, day, hours, 0, 0, 0).getTime();
    }
    intervalBounds(now) {
        const unit = this.options.interval.unit;
        if (unit === "M" || unit === "d" || unit === "h")
            this.intervalBoundsBig(now);
        else {
            let period = 1000 * this.options.interval.num;
            if (unit === "m")
                period *= 60;
            this.prev = parseInt((now.getTime() / period), 10) * period;
            this.next = this.prev + period;
        }
        return new Date(this.prev);
    }
    interval() {
        if (!this.options.interval)
            return;
        this.intervalBounds(this.now());
        const set = async () => {
            const time = this.next - this.now().getTime();
            if (time <= 0) {
                try {
                    this.timeoutPromise = this.rotate();
                    await this.timeoutPromise;
                    delete this.timeoutPromise;
                }
                catch (e) { }
            }
            else {
                this.timeout = setTimeout(set, time > this.maxTimeout ? this.maxTimeout : time);
                this.timeout.unref();
            }
        };
        set();
    }
    async compress(filename) {
        const { compress } = this.options;
        if (typeof compress === "function") {
            await new Promise((resolve, reject) => {
                this.exec(compress(this.filename, filename), (error, stdout, stderr) => {
                    this.emit("external", stdout, stderr);
                    error ? reject(error) : resolve();
                });
            });
        }
        else
            await this.gzip(filename);
        return this.unlink(this.filename);
    }
    async gzip(filename) {
        const { mode } = this.options;
        const options = mode ? { mode } : {};
        const inp = this.fsCreateReadStream(this.filename, {});
        const out = this.fsCreateWriteStream(filename, options);
        const zip = this.createGzip();
        return new Promise((resolve, reject) => {
            [inp, out, zip].map(stream => stream.once("error", reject));
            out.once("finish", resolve);
            inp.pipe(zip).pipe(out);
        });
    }
    async rotated(filename) {
        const { maxFiles, maxSize } = this.options;
        if (maxFiles || maxSize)
            await this.history(filename);
        this.emit("rotated", filename);
        return this.reopen(0);
    }
    async history(filename) {
        const { history, maxFiles, maxSize } = this.options;
        const res = [];
        let files = [filename];
        try {
            const content = await this.fsReadFile(history, "utf8");
            files = [...content.toString().split("\n"), filename];
        }
        catch (e) {
            if (e.code !== "ENOENT")
                throw e;
        }
        for (const file of files) {
            if (file) {
                try {
                    const stats = await this.fsStat(file);
                    if (stats.isFile()) {
                        res.push({
                            name: file,
                            size: stats.size,
                            time: stats.ctime.getTime()
                        });
                    }
                    else
                        this.emit("warning", new Error(`File '${file}' contained in history is not a regular file`));
                }
                catch (e) {
                    if (e.code !== "ENOENT")
                        throw e;
                }
            }
        }
        res.sort((a, b) => a.time - b.time);
        if (maxFiles) {
            while (res.length > maxFiles) {
                const file = res.shift();
                await this.unlink(file.name);
                this.emit("removed", file.name, true);
            }
        }
        if (maxSize) {
            while (res.reduce((size, file) => size + file.size, 0) > maxSize) {
                const file = res.shift();
                await this.unlink(file.name);
                this.emit("removed", file.name, false);
            }
        }
        await writeFile(history, res.map(e => e.name).join("\n") + "\n", "utf-8");
        this.emit("history");
    }
    async immutate(first) {
        const { size } = this.options;
        const now = this.now();
        for (let index = 1; index < 1000; ++index) {
            let fileSize = 0;
            let stats = undefined;
            this.filename = this.options.path + this.generator(now, index);
            try {
                stats = await this.fsStat(this.filename);
            }
            catch (e) {
                if (e.code !== "ENOENT")
                    throw e;
            }
            if (stats) {
                fileSize = stats.size;
                if (!stats.isFile())
                    throw new Error(`Can't write on: '${this.filename}' (it is not a file)`);
                if (size && fileSize >= size)
                    continue;
            }
            if (first) {
                this.last = this.filename;
                return this.reopen(fileSize);
            }
            await this.rotated(this.last);
            this.last = this.filename;
            return;
        }
        throw new RotatingFileStreamError();
    }
    async unlink(filename) {
        try {
            await this.fsUnlink(filename);
        }
        catch (e) {
            if (e.code !== "ENOENT")
                throw e;
            this.emit("warning", e);
        }
    }
}
function buildNumberCheck(field) {
    return (type, options, value) => {
        const converted = parseInt(value, 10);
        if (type !== "number" || converted !== value || converted <= 0)
            throw new Error(`'${field}' option must be a positive integer number`);
    };
}
function buildStringCheck(field, check) {
    return (type, options, value) => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.${field}' type: ${type}`);
        options[field] = check(value);
    };
}
function checkMeasure(value, what, units) {
    const ret = {};
    ret.num = parseInt(value, 10);
    if (isNaN(ret.num))
        throw new Error(`Unknown 'options.${what}' format: ${value}`);
    if (ret.num <= 0)
        throw new Error(`A positive integer number is expected for 'options.${what}'`);
    ret.unit = value.replace(/^[ 0]*/g, "").substr((ret.num + "").length, 1);
    if (ret.unit.length === 0)
        throw new Error(`Missing unit for 'options.${what}'`);
    if (!units[ret.unit])
        throw new Error(`Unknown 'options.${what}' unit: ${ret.unit}`);
    return ret;
}
const intervalUnits = { M: true, d: true, h: true, m: true, s: true };
function checkIntervalUnit(ret, unit, amount) {
    if (parseInt((amount / ret.num), 10) * ret.num !== amount)
        throw new Error(`An integer divider of ${amount} is expected as ${unit} for 'options.interval'`);
}
function checkInterval(value) {
    const ret = checkMeasure(value, "interval", intervalUnits);
    switch (ret.unit) {
        case "h":
            checkIntervalUnit(ret, "hours", 24);
            break;
        case "m":
            checkIntervalUnit(ret, "minutes", 60);
            break;
        case "s":
            checkIntervalUnit(ret, "seconds", 60);
            break;
    }
    return ret;
}
const sizeUnits = { B: true, G: true, K: true, M: true };
function checkSize(value) {
    const ret = checkMeasure(value, "size", sizeUnits);
    if (ret.unit === "K")
        return ret.num * 1024;
    if (ret.unit === "M")
        return ret.num * 1048576;
    if (ret.unit === "G")
        return ret.num * 1073741824;
    return ret.num;
}
const checks = {
    encoding: (type, options, value) => new TextDecoder(value),
    immutable: () => { },
    initialRotation: () => { },
    interval: buildStringCheck("interval", checkInterval),
    intervalBoundary: () => { },
    intervalUTC: () => { },
    maxFiles: buildNumberCheck("maxFiles"),
    maxSize: buildStringCheck("maxSize", checkSize),
    mode: () => { },
    omitExtension: () => { },
    rotate: buildNumberCheck("rotate"),
    size: buildStringCheck("size", checkSize),
    teeToStdout: () => { },
    ...{
        compress: (type, options, value) => {
            if (!value)
                throw new Error("A value for 'options.compress' must be specified");
            if (type === "boolean")
                return (options.compress = (source, dest) => `cat ${source} | gzip -c9 > ${dest}`);
            if (type === "function")
                return;
            if (type !== "string")
                throw new Error(`Don't know how to handle 'options.compress' type: ${type}`);
            if (value !== "gzip")
                throw new Error(`Don't know how to handle compression method: ${value}`);
        },
        history: (type) => {
            if (type !== "string")
                throw new Error(`Don't know how to handle 'options.history' type: ${type}`);
        },
        path: (type, options, value) => {
            if (type !== "string")
                throw new Error(`Don't know how to handle 'options.path' type: ${type}`);
            if (value[value.length - 1] !== sep)
                options.path = value + sep;
        }
    }
};
function checkOpts(options) {
    const ret = {};
    let opt;
    for (opt in options) {
        const value = options[opt];
        const type = typeof value;
        if (!(opt in checks))
            throw new Error(`Unknown option: ${opt}`);
        ret[opt] = options[opt];
        checks[opt](type, ret, value);
    }
    if (!ret.path)
        ret.path = "";
    if (!ret.interval) {
        delete ret.immutable;
        delete ret.initialRotation;
        delete ret.intervalBoundary;
        delete ret.intervalUTC;
    }
    if (ret.rotate) {
        delete ret.history;
        delete ret.immutable;
        delete ret.maxFiles;
        delete ret.maxSize;
        delete ret.intervalBoundary;
        delete ret.intervalUTC;
    }
    if (ret.immutable)
        delete ret.compress;
    if (!ret.intervalBoundary)
        delete ret.initialRotation;
    return ret;
}
function createClassical(filename, compress, omitExtension) {
    return (index) => (index ? `${filename}.${index}${compress && !omitExtension ? ".gz" : ""}` : filename);
}
function createGenerator(filename, compress, omitExtension) {
    const pad = (num) => (num > 9 ? "" : "0") + num;
    return (time, index) => {
        if (!time)
            return filename;
        const month = time.getFullYear() + "" + pad(time.getMonth() + 1);
        const day = pad(time.getDate());
        const hour = pad(time.getHours());
        const minute = pad(time.getMinutes());
        return month + day + "-" + hour + minute + "-" + pad(index) + "-" + filename + (compress && !omitExtension ? ".gz" : "");
    };
}
export function createStream(filename, options) {
    if (typeof options === "undefined")
        options = {};
    else if (typeof options !== "object")
        throw new Error(`The "options" argument must be of type object. Received type ${typeof options}`);
    const opts = checkOpts(options);
    const { compress, omitExtension } = opts;
    let generator;
    if (typeof filename === "string")
        generator = options.rotate ? createClassical(filename, compress !== undefined, omitExtension) : createGenerator(filename, compress !== undefined, omitExtension);
    else if (typeof filename === "function")
        generator = filename;
    else
        throw new Error(`The "filename" argument must be one of type string or function. Received type ${typeof filename}`);
    return new RotatingFileStream(generator, opts);
}