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

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

import { sep } from "node:path";
import { Writable } from "node:stream";
import { TextDecoder } from "node:util";
export class RotatingFileStreamError extends Error {
    code = "RFS-TOO-MANY";
    constructor() {
        super("Too many destination file attempts");
    }
}
/* eslint-enable @typescript-eslint/no-unused-vars */
// Dummy implementation: only stores constructor args for now.
export class RotatingFileStream extends Writable {
    generator;
    options;
    constructor(generator, options) {
        super({ decodeStrings: true, defaultEncoding: options.encoding });
        this.generator = generator;
        this.options = options;
    }
}
const sizeUnits = { B: true, G: true, K: true, M: true };
const intervalUnits = { d: true, h: true, m: true, M: true, s: true };
const noopChecker = () => undefined;
const assertPositiveInteger = (field, type, value) => {
    const converted = parseInt(value, 10);
    if (type !== "number" || converted !== value || converted <= 0)
        throw new Error(`'${field}' option must be a positive integer number`);
};
const parseMeasure = (value, what, units) => {
    const num = parseInt(value, 10);
    if (Number.isNaN(num))
        throw new Error(`Unknown 'options.${what}' format: ${value}`);
    if (num <= 0)
        throw new Error(`A positive integer number is expected for 'options.${what}'`);
    const unit = value.replace(/^[ 0]*/g, "").slice(String(num).length, String(num).length + 1);
    if (!unit)
        throw new Error(`Missing unit for 'options.${what}'`);
    if (!units[unit])
        throw new Error(`Unknown 'options.${what}' unit: ${unit}`);
    return { num, unit };
};
const parseSize = (value, what) => {
    const { num, unit } = parseMeasure(value, what, sizeUnits);
    if (unit === "K")
        return num * 1024;
    if (unit === "M")
        return num * 1048576;
    if (unit === "G")
        return num * 1073741824;
    return num;
};
const assertIntervalDivider = (num, unit, amount) => {
    if (Math.trunc(amount / num) * num !== amount)
        throw new Error(`An integer divider of ${amount} is expected as ${unit} for 'options.interval'`);
};
const parseInterval = (value) => {
    const ret = parseMeasure(value, "interval", intervalUnits);
    if (ret.unit === "h")
        assertIntervalDivider(ret.num, "hours", 24);
    if (ret.unit === "m")
        assertIntervalDivider(ret.num, "minutes", 60);
    if (ret.unit === "s")
        assertIntervalDivider(ret.num, "seconds", 60);
    return ret;
};
const checkers = {
    compress: (type, options, value) => {
        if (value === false)
            return;
        if (!value)
            throw new Error("A value for 'options.compress' must be specified");
        if (type === "boolean") {
            options.compress = (source, dest) => `cat ${source} | gzip -c9 > ${dest}`;
            return;
        }
        if (type === "function")
            return;
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.compress' type: ${type}`);
        const method = value;
        if (method !== "gzip")
            throw new Error(`Don't know how to handle compression method: ${method}`);
    },
    encoding: (_type, _options, value) => {
        new TextDecoder(value);
    },
    history: type => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.history' type: ${type}`);
    },
    immutable: noopChecker,
    initialRotation: noopChecker,
    interval: (type, options, value) => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.interval' type: ${type}`);
        options.interval = parseInterval(value);
    },
    intervalBoundary: noopChecker,
    intervalUTC: noopChecker,
    maxFiles: (type, _options, value) => assertPositiveInteger("maxFiles", type, value),
    maxSize: (type, options, value) => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.maxSize' type: ${type}`);
        options.maxSize = parseSize(value, "maxSize");
    },
    mode: noopChecker,
    omitExtension: noopChecker,
    path: (type, options, value) => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.path' type: ${type}`);
        const path = value;
        if (!path.endsWith(sep))
            options.path = path + sep;
    },
    rotate: (type, _options, value) => assertPositiveInteger("rotate", type, value),
    size: (type, options, value) => {
        if (type !== "string")
            throw new Error(`Don't know how to handle 'options.size' type: ${type}`);
        options.size = parseSize(value, "size");
    },
    teeToStdout: noopChecker
};
const checkOpts = (options) => {
    const ret = {};
    for (const opt of Object.keys(options)) {
        const value = options[opt];
        const type = typeof value;
        if (!(opt in checkers))
            throw new Error(`Unknown option: ${opt}`);
        ret[opt] = value;
        checkers[opt](type, ret, value);
    }
    if (!ret.path)
        ret.path = "";
    if (!ret.interval) {
        delete ret.immutable;
        delete ret.initialRotation;
        delete ret.intervalBoundary;
        delete ret.intervalUTC;
    }
    if (ret.rotate) {
        delete ret.history;
        delete ret.immutable;
        delete ret.maxFiles;
        delete ret.maxSize;
        delete ret.intervalBoundary;
        delete ret.intervalUTC;
    }
    if (ret.immutable)
        delete ret.compress;
    if (!ret.intervalBoundary)
        delete ret.initialRotation;
    return ret;
};
const pad = (num) => `${num > 9 ? "" : "0"}${num}`;
const createClassical = (filename, compress, omitExtension) => (index) => index ? `${filename}.${index}${compress && !omitExtension ? ".gz" : ""}` : filename;
const createGenerator = (filename, compress, omitExtension) => (time, index) => {
    if (!time)
        return filename;
    const date = time instanceof Date ? time : new Date(time);
    const month = `${date.getFullYear()}${pad(date.getMonth() + 1)}`;
    const day = pad(date.getDate());
    const hour = pad(date.getHours());
    const minute = pad(date.getMinutes());
    return `${month}${day}-${hour}${minute}-${pad(index ?? 0)}-${filename}${compress && !omitExtension ? ".gz" : ""}`;
};
export const createStream = (filename, options) => {
    const rawOptions = options;
    if (rawOptions === undefined)
        options = {};
    else if (typeof rawOptions !== "object" || rawOptions === null)
        throw new Error(`The "options" argument must be of type object. Received type ${typeof rawOptions}`);
    else
        options = rawOptions;
    const opts = checkOpts(options);
    const { compress, omitExtension } = opts;
    let generator;
    if (typeof filename === "string") {
        generator = opts.rotate
            ? createClassical(filename, Boolean(compress), Boolean(omitExtension))
            : createGenerator(filename, Boolean(compress), Boolean(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);
};