Simplify and speed up trace context parsing

[dyladan]

Which problem is this PR solving?

• Speeds up the trace context parser significantly

Short description of the changes

• Remove duplicate validity checks
• Condense validity check and parsing into a single step

Benchmark

On my machine I achieved a ~2X speedup

➜  testbed node index.js

  2 tests completed.

  old x 1,835,685 ops/sec ±0.46% (93 runs sampled)
  new x 3,499,510 ops/sec ±0.32% (96 runs sampled)

Based on this benchmark code:

const Benchmark = require('benchmark');
const pretty = require('beautify-benchmark');

const VALID_TRACE_PARENT_REGEX_NEW = /^00-([\da-f]{32})-([\da-f]{16})-([\da-f]{2})$/;
const VALID_TRACE_PARENT_REGEX = /^[\da-f]{2}-[\da-f]{32}-[\da-f]{16}-[\da-f]{2}$/;
const VALID_TRACEID_REGEX = /^[0-9a-f]{32}$/i;
const VALID_SPANID_REGEX = /^[0-9a-f]{16}$/i;
const INVALID_ID_REGEX = /^0+$/i;
const VERSION = '00';

const suite = new Benchmark.Suite()
    .on('cycle', event => pretty.add(event.target))
    .on('error', event => { throw event.target.error; })
    .on('complete', function () { pretty.log(); });

suite
    .add("old", () => parseTraceParent("00-d4cda95b652f4a1592b449d5929fda1b-6e0c63257de34c92-00"))
    .add("new", () => newParseTraceParent("00-d4cda95b652f4a1592b449d5929fda1b-6e0c63257de34c92-00"));

suite.run();

function newParseTraceParent(traceParent) {
    const match = traceParent.match(VALID_TRACE_PARENT_REGEX_NEW);
    if (
        !match ||
        match[1] === '00000000000000000000000000000000' ||
        match[2] === '0000000000000000'
    ) {
        return null;
    }

    return { traceId: match[1], spanId: match[2], traceFlags: parseInt(match[3], 16) };
}

function parseTraceParent(traceParent) {
    const match = traceParent.match(VALID_TRACE_PARENT_REGEX);
    if (!match) return null;
    const parts = traceParent.split('-');
    const [version, traceId, spanId, option] = parts;
    const traceFlags = parseInt(option, 16);

    if (
        !isValidVersion(version) ||
        !isValidTraceId(traceId) ||
        !isValidSpanId(spanId)
    ) {
        return null;
    }

    return { traceId, spanId, traceFlags };
}

function isValidVersion(version) {
    return version === VERSION;
}

function isValidTraceId(traceId) {
    return VALID_TRACEID_REGEX.test(traceId) && !INVALID_ID_REGEX.test(traceId);
}

function isValidSpanId(spanId) {
    return VALID_SPANID_REGEX.test(spanId) && !INVALID_ID_REGEX.test(spanId);
}

[codecov-io]

Codecov Report

Merging #708 into master will decrease coverage by 1.79%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master     #708     +/-   ##
=========================================
- Coverage   92.69%   90.89%   -1.8%     
=========================================
  Files         228      225      -3     
  Lines       10411    10305    -106     
  Branches      939      957     +18     
=========================================
- Hits         9650     9367    -283     
- Misses        761      938    +177

Impacted Files	Coverage Δ
packages/opentelemetry-core/test/utils/url.test.ts	50% <0%> (-50%)	⬇️
...pentelemetry-core/test/internal/validators.test.ts	50% <0%> (-50%)	⬇️
...elemetry-core/test/trace/spancontext-utils.test.ts	55.55% <0%> (-44.45%)	⬇️
...lemetry-core/test/trace/ProbabilitySampler.test.ts	56.52% <0%> (-43.48%)	⬇️
...s/opentelemetry-core/test/trace/NoopTracer.test.ts	60% <0%> (-40%)	⬇️
...s/opentelemetry-core/test/context/B3Format.test.ts	63.39% <0%> (-36.61%)	⬇️
...ges/opentelemetry-core/test/trace/NoopSpan.test.ts	63.63% <0%> (-36.37%)	⬇️
...s/opentelemetry-core/test/trace/tracestate.test.ts	65.06% <0%> (-34.94%)	⬇️
...ntelemetry-core/test/trace/NoRecordingSpan.test.ts	71.42% <0%> (-28.58%)	⬇️
...ackages/opentelemetry-core/src/platform/node/id.ts	71.42% <0%> (-28.58%)	⬇️
... and 41 more

[OlivierAlbertini]

Good job!

[mayurkale22]

Nice 💯