zulip/static/js/blueslip.js

/* eslint-disable no-console */

// System documented in https://zulip.readthedocs.io/en/latest/subsystems/logging.html

// This must be included before the first call to $(document).ready
// in order to be able to report exceptions that occur during their
// execution.

import $ from "jquery";

import * as blueslip_stacktrace from "./blueslip_stacktrace";
import {page_params} from "./page_params";
import * as ui_report from "./ui_report";

if (Error.stackTraceLimit !== undefined) {
    Error.stackTraceLimit = 100000;
}

function pad(num, width) {
    return num.toString().padStart(width, "0");
}

function make_logger_func(name) {
    return function Logger_func(...args) {
        const now = new Date();
        const date_str =
            now.getUTCFullYear() +
            "-" +
            pad(now.getUTCMonth() + 1, 2) +
            "-" +
            pad(now.getUTCDate(), 2) +
            " " +
            pad(now.getUTCHours(), 2) +
            ":" +
            pad(now.getUTCMinutes(), 2) +
            ":" +
            pad(now.getUTCSeconds(), 2) +
            "." +
            pad(now.getUTCMilliseconds(), 3) +
            " UTC";

        const str_args = args.map((x) => (typeof x === "object" ? JSON.stringify(x) : x));

        const log_entry = date_str + " " + name.toUpperCase() + ": " + str_args.join("");
        this._memory_log.push(log_entry);

        // Don't let the log grow without bound
        if (this._memory_log.length > 1000) {
            this._memory_log.shift();
        }

        if (console[name] !== undefined) {
            return console[name](...args);
        }
    };
}

class Logger {
    _memory_log = [];

    get_log() {
        return this._memory_log;
    }
}

for (const name of ["debug", "log", "info", "warn", "error"]) {
    Logger.prototype[name] = make_logger_func(name);
}

const logger = new Logger();

export function get_log() {
    return logger.get_log();
}

const reported_errors = new Set();
const last_report_attempt = new Map();

function report_error(
    msg,
    stack = "No stacktrace available",
    {show_ui_msg = false, more_info} = {},
) {
    if (page_params.debug_mode) {
        // In development, we display blueslip errors in the web UI,
        // to make them hard to miss.
        blueslip_stacktrace.display_stacktrace(msg, stack);
    }

    const key = ":" + msg + stack;
    if (
        reported_errors.has(key) ||
        (last_report_attempt.has(key) &&
            // Only try to report a given error once every 5 minutes
            Date.now() - last_report_attempt.get(key) <= 60 * 5 * 1000)
    ) {
        return;
    }

    last_report_attempt.set(key, Date.now());

    // TODO: If an exception gets thrown before we set up ajax calls
    // to include the CSRF token, our ajax call will fail.  The
    // elegant thing to do in that case is to either wait until that
    // setup is done or do it ourselves and then retry.
    //
    // Important: We don't use channel.js here so that exceptions
    // always make it to the server even if reload_state.is_in_progress.
    $.ajax({
        type: "POST",
        url: "/json/report/error",
        dataType: "json",
        data: {
            message: msg,
            stacktrace: stack,
            ui_message: show_ui_msg,
            more_info: JSON.stringify(more_info),
            href: window.location.href,
            user_agent: window.navigator.userAgent,
            log: logger.get_log().join("\n"),
        },
        timeout: 3 * 1000,
        success() {
            reported_errors.add(key);
            if (show_ui_msg && ui_report !== undefined) {
                // There are a few races here (and below in the error
                // callback):
                // 1) The ui_report module or something it requires might
                //    not have been compiled or initialized yet.
                // 2) The DOM might not be ready yet and so fetching
                //    the #home-error div might fail.

                // For (1) we just don't show the message if the ui
                // hasn't been loaded yet.  The user will probably
                // get another error once it does.  We can't solve
                // (2) by using $(document).ready because the
                // callback never gets called (I think what's going
                // on here is if the exception was raised by a
                // function that was called as a result of the DOM
                // becoming ready then the internal state of jQuery
                // gets messed up and our callback never gets
                // invoked).  In any case, it will pretty clear that
                // something is wrong with the page and the user will
                // probably try to reload anyway.
                ui_report.client_error(
                    "Oops.  It seems something has gone wrong. " +
                        "The error has been reported to the fine " +
                        "folks at Zulip, but, in the mean time, " +
                        "please try reloading the page.",
                    $("#home-error"),
                );
            }
        },
        error() {
            if (show_ui_msg && ui_report !== undefined) {
                ui_report.client_error(
                    "Oops.  It seems something has gone wrong. Please try reloading the page.",
                    $("#home-error"),
                );
            }
        },
    });

    if (page_params.save_stacktraces) {
        // Save the stacktrace so it can be examined even in
        // development servers.  (N.B. This assumes you have set DEBUG
        // = False on your development server, or else this code path
        // won't execute to begin with -- useful for testing
        // (un)minification.)
        window.last_stacktrace = stack;
    }
}

class BlueslipError extends Error {
    name = "BlueslipError";

    constructor(msg, more_info) {
        super(msg);
        if (more_info !== undefined) {
            this.more_info = more_info;
        }
    }
}

export function exception_msg(ex) {
    let message = ex.message;
    if (ex.fileName !== undefined) {
        message += " at " + ex.fileName;
        if (ex.lineNumber !== undefined) {
            message += ":" + ex.lineNumber;
        }
    }
    return message;
}

$(window).on("error", (event) => {
    const ex = event.originalEvent.error;
    if (!ex || ex instanceof BlueslipError) {
        return;
    }
    const message = exception_msg(ex);
    report_error(message, ex.stack);
});

function build_arg_list(msg, more_info) {
    const args = [msg];
    if (more_info !== undefined) {
        args.push("\nAdditional information: ", more_info);
    }
    return args;
}

export function debug(msg, more_info) {
    const args = build_arg_list(msg, more_info);
    logger.debug(...args);
}

export function log(msg, more_info) {
    const args = build_arg_list(msg, more_info);
    logger.log(...args);
}

export function info(msg, more_info) {
    const args = build_arg_list(msg, more_info);
    logger.info(...args);
}

export function warn(msg, more_info) {
    const args = build_arg_list(msg, more_info);
    logger.warn(...args);
    if (page_params.debug_mode) {
        console.trace();
    }
}

export function error(msg, more_info, stack = new Error("dummy").stack) {
    const args = build_arg_list(msg, more_info);
    logger.error(...args);
    report_error(msg, stack, {more_info});

    if (page_params.debug_mode) {
        throw new BlueslipError(msg, more_info);
    }

    // This function returns to its caller in production!  To raise a
    // fatal error even in production, use throw new Error(…) instead.
}

export const timings = new Map();

export function measure_time(label, f) {
    const t1 = performance.now();
    const ret = f();
    const t2 = performance.now();
    const elapsed = t2 - t1;
    timings.set(label, elapsed);
    return ret;
}

// Produces an easy-to-read preview on an HTML element.  Currently
// only used for including in error report emails; be sure to discuss
// with other developers before using it in a user-facing context
// because it is not XSS-safe.
export function preview_node(node) {
    if (node instanceof $) {
        node = node[0];
    }

    const tag = node.tagName.toLowerCase();
    const className = node.className.length ? node.className : false;
    const id = node.id.length ? node.id : false;

    const node_preview =
        "<" +
        tag +
        (id ? " id='" + id + "'" : "") +
        (className ? " class='" + className + "'" : "") +
        "></" +
        tag +
        ">";

    return node_preview;
}