152 lines
7.0 KiB
JavaScript
152 lines
7.0 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.listTags = void 0;
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/*
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* This is a TypeScript port of the original Java version, which was written by
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* Gil Tene as described in
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* https://github.com/HdrHistogram/HdrHistogram
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* and released to the public domain, as explained at
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* http://creativecommons.org/publicdomain/zero/1.0/
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*/
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const Histogram_1 = require("./Histogram");
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const encoding_1 = require("./encoding");
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const TAG_PREFIX = "Tag=";
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const TAG_PREFIX_LENGTH = "Tag=".length;
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/**
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* A histogram log reader.
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* <p>
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* Histogram logs are used to capture full fidelity, per-time-interval
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* histograms of a recorded value.
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* <p>
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* For example, a histogram log can be used to capture high fidelity
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* reaction-time logs for some measured system or subsystem component.
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* Such a log would capture a full reaction time histogram for each
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* logged interval, and could be used to later reconstruct a full
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* HdrHistogram of the measured reaction time behavior for any arbitrary
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* time range within the log, by adding [only] the relevant interval
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* histograms.
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* <h3>Histogram log format:</h3>
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* A histogram log file consists of text lines. Lines beginning with
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* the "#" character are optional and treated as comments. Lines
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* containing the legend (starting with "Timestamp") are also optional
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* and ignored in parsing the histogram log. All other lines must
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* be valid interval description lines. Text fields are delimited by
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* commas, spaces.
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* <p>
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* A valid interval description line contains an optional Tag=tagString
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* text field, followed by an interval description.
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* <p>
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* A valid interval description must contain exactly four text fields:
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* <ul>
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* <li>StartTimestamp: The first field must contain a number parse-able as a Double value,
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* representing the start timestamp of the interval in seconds.</li>
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* <li>intervalLength: The second field must contain a number parse-able as a Double value,
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* representing the length of the interval in seconds.</li>
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* <li>Interval_Max: The third field must contain a number parse-able as a Double value,
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* which generally represents the maximum value of the interval histogram.</li>
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* <li>Interval_Compressed_Histogram: The fourth field must contain a text field
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* parse-able as a Base64 text representation of a compressed HdrHistogram.</li>
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* </ul>
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* The log file may contain an optional indication of a starting time. Starting time
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* is indicated using a special comments starting with "#[StartTime: " and followed
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* by a number parse-able as a double, representing the start time (in seconds)
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* that may be added to timestamps in the file to determine an absolute
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* timestamp (e.g. since the epoch) for each interval.
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*/
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class HistogramLogReader {
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constructor(logContent, bitBucketSize = 32, useWebAssembly = false) {
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this.lines = splitLines(logContent);
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this.currentLineIndex = 0;
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this.bitBucketSize = bitBucketSize;
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this.useWebAssembly = useWebAssembly;
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}
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/**
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* Read the next interval histogram from the log. Returns a Histogram object if
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* an interval line was found, or null if not.
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* <p>Upon encountering any unexpected format errors in reading the next interval
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* from the file, this method will return a null.
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* @return a DecodedInterval, or a null if no appropriate interval found
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*/
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nextIntervalHistogram(rangeStartTimeSec = 0, rangeEndTimeSec = Number.MAX_VALUE) {
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while (this.currentLineIndex < this.lines.length) {
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const currentLine = this.lines[this.currentLineIndex];
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this.currentLineIndex++;
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if (currentLine.startsWith("#[StartTime:")) {
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this.parseStartTimeFromLine(currentLine);
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}
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else if (currentLine.startsWith("#[BaseTime:")) {
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this.parseBaseTimeFromLine(currentLine);
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}
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else if (currentLine.startsWith("#") ||
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currentLine.startsWith('"StartTimestamp"')) {
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// skip legend & meta data for now
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}
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else if (currentLine.includes(",")) {
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const tokens = currentLine.split(",");
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const [firstToken] = tokens;
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let tag;
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if (firstToken.startsWith(TAG_PREFIX)) {
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tag = firstToken.substring(TAG_PREFIX_LENGTH);
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tokens.shift();
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}
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else {
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tag = Histogram_1.NO_TAG;
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}
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const [rawLogTimeStampInSec, rawIntervalLengthSec, , base64Histogram,] = tokens;
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const logTimeStampInSec = Number.parseFloat(rawLogTimeStampInSec);
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if (!this.baseTimeSec) {
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// No explicit base time noted. Deduce from 1st observed time (compared to start time):
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if (logTimeStampInSec < this.startTimeSec - 365 * 24 * 3600.0) {
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// Criteria Note: if log timestamp is more than a year in the past (compared to
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// StartTime), we assume that timestamps in the log are not absolute
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this.baseTimeSec = this.startTimeSec;
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}
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else {
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// Timestamps are absolute
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this.baseTimeSec = 0.0;
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}
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}
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if (rangeEndTimeSec < logTimeStampInSec) {
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return null;
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}
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if (logTimeStampInSec < rangeStartTimeSec) {
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continue;
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}
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const histogram = encoding_1.decodeFromCompressedBase64(base64Histogram, this.bitBucketSize, this.useWebAssembly);
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histogram.startTimeStampMsec =
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(this.baseTimeSec + logTimeStampInSec) * 1000;
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const intervalLengthSec = Number.parseFloat(rawIntervalLengthSec);
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histogram.endTimeStampMsec =
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(this.baseTimeSec + logTimeStampInSec + intervalLengthSec) * 1000;
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histogram.tag = tag;
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return histogram;
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}
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}
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return null;
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}
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parseStartTimeFromLine(line) {
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this.startTimeSec = Number.parseFloat(line.split(" ")[1]);
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}
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parseBaseTimeFromLine(line) {
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this.baseTimeSec = Number.parseFloat(line.split(" ")[1]);
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}
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}
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const splitLines = (logContent) => logContent.split(/\r\n|\r|\n/g);
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const shouldIncludeNoTag = (lines) => lines.find((line) => !line.startsWith("#") &&
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!line.startsWith('"') &&
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!line.startsWith(TAG_PREFIX) &&
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line.includes(","));
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exports.listTags = (content) => {
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const lines = splitLines(content);
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const tags = lines
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.filter((line) => line.includes(",") && line.startsWith(TAG_PREFIX))
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.map((line) => line.substring(TAG_PREFIX_LENGTH, line.indexOf(",")));
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const tagsWithoutDuplicates = new Set(tags);
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const result = Array.from(tagsWithoutDuplicates);
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if (shouldIncludeNoTag(lines)) {
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result.unshift("NO TAG");
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}
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return result;
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};
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exports.default = HistogramLogReader;
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//# sourceMappingURL=HistogramLogReader.js.map
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