chore(refactor): rename some files and classes for ease of understanding (#6934)

* Chunk -> MsgpackChunk

* format.js -> span_format.js

* Writer -> AgentWriter

* remove setHeader()

Author: tlhunter

benchmark/core.js

@@ -19,7 +19,7 @@ const Writer = proxyquire('../packages/dd-trace/src/exporters/agent/writer', {
   }
 })
 const Sampler = require('../packages/dd-trace/src/sampler')
-const format = require('../packages/dd-trace/src/format')
+const spanFormat = require('../packages/dd-trace/src/span_format')
 const { AgentEncoder: Agent04Encoder } = require('../packages/dd-trace/src/encode/0.4')
 const { AgentEncoder: Agent05Encoder } = require('../packages/dd-trace/src/encode/0.5')
 const config = getConfig({ service: 'benchmark' })
@@ -42,7 +42,7 @@ let writer
 let sampler
 
 const spanStub = require('./stubs/span')
-const span = format(spanStub)
+const span = spanFormat(spanStub)
 
 suite
   .add('DatadogTracer#startSpan', {
@@ -96,9 +96,9 @@ suite
       sampler.isSampled(span)
     }
   })
-  .add('format', {
+  .add('spanFormat', {
     fn () {
-      format(spanStub)
+      spanFormat(spanStub)
     }
   })
   .add('encode (0.4)', {

packages/dd-trace/src/encode/0.4.js

@@ -1,7 +1,7 @@
 'use strict'
 
 const { truncateSpan, normalizeSpan } = require('./tags-processors')
-const { Chunk, MsgpackEncoder } = require('../msgpack')
+const { MsgpackChunk, MsgpackEncoder } = require('../msgpack')
 const log = require('../log')
 const { isTrue } = require('../util')
 const { memoize } = require('../log/utils')
@@ -27,8 +27,8 @@ class AgentEncoder {
   constructor (writer, limit = SOFT_LIMIT) {
     this._msgpack = new MsgpackEncoder()
     this._limit = limit
-    this._traceBytes = new Chunk()
-    this._stringBytes = new Chunk()
+    this._traceBytes = new MsgpackChunk()
+    this._stringBytes = new MsgpackChunk()
     this._writer = writer
     this._reset()
     this._debugEncoding = isTrue(getEnvironmentVariable('DD_TRACE_ENCODING_DEBUG'))

packages/dd-trace/src/encode/coverage-ci-visibility.js

@@ -1,6 +1,6 @@
 'use strict'
 const { AgentEncoder } = require('./0.4')
-const { Chunk } = require('../msgpack')
+const { MsgpackChunk } = require('../msgpack')
 
 const {
   distributionMetric,
@@ -15,7 +15,7 @@ const COVERAGE_KEYS_LENGTH = 2
 class CoverageCIVisibilityEncoder extends AgentEncoder {
   constructor () {
     super(...arguments)
-    this._coverageBytes = new Chunk()
+    this._coverageBytes = new MsgpackChunk()
     this.form = new FormData()
     this._coveragesCount = 0
     this.reset()

packages/dd-trace/src/exporters/agent/writer.js

@@ -9,7 +9,7 @@ const BaseWriter = require('../common/writer')
 
 const METRIC_PREFIX = 'datadog.tracer.node.exporter.agent'
 
-class Writer extends BaseWriter {
+class AgentWriter extends BaseWriter {
   constructor ({ prioritySampler, lookup, protocolVersion, headers, config = {} }) {
     super(...arguments)
     const AgentEncoder = getEncoder(protocolVersion)
@@ -62,12 +62,6 @@ class Writer extends BaseWriter {
   }
 }
 
-function setHeader (headers, key, value) {
-  if (value) {
-    headers[key] = value
-  }
-}
-
 function getEncoder (protocolVersion) {
   return protocolVersion === '0.5'
     ? require('../../encode/0.5').AgentEncoder
@@ -82,16 +76,15 @@ function makeRequest (version, data, count, url, headers, lookup, needsStartupLo
       ...headers,
       'Content-Type': 'application/msgpack',
       'Datadog-Meta-Tracer-Version': tracerVersion,
-      'X-Datadog-Trace-Count': String(count)
+      'X-Datadog-Trace-Count': String(count),
+      'Datadog-Meta-Lang': 'nodejs',
+      'Datadog-Meta-Lang-Version': process.version,
+      'Datadog-Meta-Lang-Interpreter': process.jsEngine || 'v8'
     },
     lookup,
     url
   }
 
-  setHeader(options.headers, 'Datadog-Meta-Lang', 'nodejs')
-  setHeader(options.headers, 'Datadog-Meta-Lang-Version', process.version)
-  setHeader(options.headers, 'Datadog-Meta-Lang-Interpreter', process.jsEngine || 'v8')
-
   log.debug('Request to the agent: %j', options)
 
   request(data, options, (err, res, status) => {
@@ -105,4 +98,4 @@ function makeRequest (version, data, count, url, headers, lookup, needsStartupLo
   })
 }
 
-module.exports = Writer
+module.exports = AgentWriter

packages/dd-trace/src/msgpack/chunk.js

@@ -7,7 +7,7 @@ const DEFAULT_MIN_SIZE = 2 * 1024 * 1024 // 2MB
  * interfaces so that it can be used seamlessly by any encoder code that expects
  * either.
  */
-class Chunk {
+class MsgpackChunk {
   constructor (minSize = DEFAULT_MIN_SIZE) {
     this.buffer = Buffer.allocUnsafe(minSize)
     this.view = new DataView(this.buffer.buffer)
@@ -66,4 +66,4 @@ class Chunk {
   }
 }
 
-module.exports = Chunk
+module.exports = MsgpackChunk

packages/dd-trace/src/msgpack/encoder.js

@@ -1,11 +1,10 @@
 'use strict'
 
-const Chunk = require('./chunk')
+const MsgpackChunk = require('./chunk')
 
 class MsgpackEncoder {
   encode (value) {
-    const bytes = new Chunk()
-
+    const bytes = new MsgpackChunk()
     this.encodeValue(bytes, value)
 
     return bytes.buffer.subarray(0, bytes.length)

packages/dd-trace/src/msgpack/index.js

@@ -1,6 +1,6 @@
 'use strict'
 
-const Chunk = require('./chunk')
+const MsgpackChunk = require('./chunk')
 const { MsgpackEncoder } = require('./encoder')
 
-module.exports = { Chunk, MsgpackEncoder }
+module.exports = { MsgpackChunk, MsgpackEncoder }

packages/dd-trace/src/format.js renamed to packages/dd-trace/src/span_format.js

@@ -1,7 +1,7 @@
 'use strict'
 
 const log = require('./log')
-const format = require('./format')
+const spanFormat = require('./span_format')
 const SpanSampler = require('./span_sampler')
 const GitMetadataTagger = require('./git_metadata_tagger')
 const { getEnvironmentVariable } = require('./config-helper')
@@ -53,7 +53,7 @@ class SpanProcessor {
         if (span._duration === undefined) {
           active.push(span)
         } else {
-          const formattedSpan = format(span, isChunkRoot)
+          const formattedSpan = spanFormat(span, isChunkRoot)
           isChunkRoot = false
           this._stats?.onSpanFinished(formattedSpan)
           formatted.push(formattedSpan)

packages/dd-trace/src/span_processor.js

@@ -19,7 +19,7 @@ const { NoopSpanProcessor } = require('../../src/opentelemetry/span_processor')
 const { ERROR_MESSAGE, ERROR_STACK, ERROR_TYPE, IGNORE_OTEL_ERROR } = require('../../src/constants')
 const { SERVICE_NAME, RESOURCE_NAME, SPAN_KIND } = require('../../../../ext/tags')
 const kinds = require('../../../../ext/kinds')
-const format = require('../../src/format')
+const spanFormat = require('../../src/span_format')
 
 const spanKindNames = {
   [api.SpanKind.INTERNAL]: kinds.INTERNAL,
@@ -406,20 +406,20 @@ describe('OTel Span', () => {
       startTime: datenow
     }])
 
-    let formatted = format(span._ddSpan)
+    let formatted = spanFormat(span._ddSpan)
     expect(formatted).to.have.property('error', 0)
     expect(formatted.meta).to.not.have.property('doNotSetTraceError')
 
     // Set error code
     span.setStatus({ code: 2, message: 'error' })
 
-    formatted = format(span._ddSpan)
+    formatted = spanFormat(span._ddSpan)
     expect(formatted).to.have.property('error', 1)
 
     span.recordException(new Error('foobar'), Date.now())
 
     // Keep the error set to 1
-    formatted = format(span._ddSpan)
+    formatted = spanFormat(span._ddSpan)
     expect(formatted).to.have.property('error', 1)
     expect(formatted).to.have.property('meta')
     expect(formatted.meta).to.have.property('error.message', 'foobar')