rollbar/src/truncation.js

Effortlessly track and debug errors in your JavaScript applications with Rollbar. This package includes advanced error tracking features and an intuitive interface to help you identify and fix issues more quickly.

var _ = require('./utility');
var traverse = require('./utility/traverse');

function raw(payload, jsonBackup) {
  return [payload, _.stringify(payload, jsonBackup)];
}

function selectFrames(frames, range) {
  var len = frames.length;
  if (len > range * 2) {
    return frames.slice(0, range).concat(frames.slice(len - range));
  }
  return frames;
}

function truncateFrames(payload, jsonBackup, range) {
  range = typeof range === 'undefined' ? 30 : range;
  var body = payload.data.body;
  var frames;
  if (body.trace_chain) {
    var chain = body.trace_chain;
    for (var i = 0; i < chain.length; i++) {
      frames = chain[i].frames;
      frames = selectFrames(frames, range);
      chain[i].frames = frames;
    }
  } else if (body.trace) {
    frames = body.trace.frames;
    frames = selectFrames(frames, range);
    body.trace.frames = frames;
  }
  return [payload, _.stringify(payload, jsonBackup)];
}

function maybeTruncateValue(len, val) {
  if (!val) {
    return val;
  }
  if (val.length > len) {
    return val.slice(0, len - 3).concat('...');
  }
  return val;
}

function truncateStrings(len, payload, jsonBackup) {
  function truncator(k, v, seen) {
    switch (_.typeName(v)) {
      case 'string':
        return maybeTruncateValue(len, v);
      case 'object':
      case 'array':
        return traverse(v, truncator, seen);
      default:
        return v;
    }
  }
  payload = traverse(payload, truncator);
  return [payload, _.stringify(payload, jsonBackup)];
}

function truncateTraceData(traceData) {
  if (traceData.exception) {
    delete traceData.exception.description;
    traceData.exception.message = maybeTruncateValue(
      255,
      traceData.exception.message,
    );
  }
  traceData.frames = selectFrames(traceData.frames, 1);
  return traceData;
}

function minBody(payload, jsonBackup) {
  var body = payload.data.body;
  if (body.trace_chain) {
    var chain = body.trace_chain;
    for (var i = 0; i < chain.length; i++) {
      chain[i] = truncateTraceData(chain[i]);
    }
  } else if (body.trace) {
    body.trace = truncateTraceData(body.trace);
  }
  return [payload, _.stringify(payload, jsonBackup)];
}

function needsTruncation(payload, maxSize) {
  return _.maxByteSize(payload) > maxSize;
}

function truncate(payload, jsonBackup, maxSize) {
  maxSize = typeof maxSize === 'undefined' ? 512 * 1024 : maxSize;
  var strategies = [
    raw,
    truncateFrames,
    truncateStrings.bind(null, 1024),
    truncateStrings.bind(null, 512),
    truncateStrings.bind(null, 256),
    minBody,
  ];
  var strategy, results, result;

  while ((strategy = strategies.shift())) {
    results = strategy(payload, jsonBackup);
    payload = results[0];
    result = results[1];
    if (result.error || !needsTruncation(result.value, maxSize)) {
      return result;
    }
  }
  return result;
}

module.exports = {
  truncate: truncate,

  /* for testing */
  raw: raw,
  truncateFrames: truncateFrames,
  truncateStrings: truncateStrings,
  maybeTruncateValue: maybeTruncateValue,
};