[DI] Improve sampling tests (#4999)

To test that multiple probes doesn't interfere with each others sample
rate, this commit also adds support for multiple breakpoints in a single
file.

integration-tests/debugger/basic.spec.js

@@ -14,7 +14,7 @@ describe('Dynamic Instrumentation', function () {
   it('base case: target app should work as expected if no test probe has been added', async function () {
     const response = await t.axios.get(t.breakpoint.url)
     assert.strictEqual(response.status, 200)
-    assert.deepStrictEqual(response.data, { hello: 'foo' })
+    assert.deepStrictEqual(response.data, { hello: 'bar' })
   })
 
   describe('diagnostics messages', function () {
@@ -54,7 +54,7 @@ describe('Dynamic Instrumentation', function () {
           t.axios.get(t.breakpoint.url)
             .then((response) => {
               assert.strictEqual(response.status, 200)
-              assert.deepStrictEqual(response.data, { hello: 'foo' })
+              assert.deepStrictEqual(response.data, { hello: 'bar' })
             })
             .catch(done)
         } else {
@@ -245,7 +245,7 @@ describe('Dynamic Instrumentation', function () {
           message: 'Hello World!',
           logger: {
             name: t.breakpoint.file,
-            method: 'handler',
+            method: 'fooHandler',
             version,
             thread_name: 'MainThread'
           },
@@ -279,7 +279,7 @@ describe('Dynamic Instrumentation', function () {
         const topFrame = payload['debugger.snapshot'].stack[0]
         // path seems to be prefeixed with `/private` on Mac
         assert.match(topFrame.fileName, new RegExp(`${t.appFile}$`))
-        assert.strictEqual(topFrame.function, 'handler')
+        assert.strictEqual(topFrame.function, 'fooHandler')
         assert.strictEqual(topFrame.lineNumber, t.breakpoint.line)
         assert.strictEqual(topFrame.columnNumber, 3)
 
@@ -375,6 +375,61 @@ describe('Dynamic Instrumentation', function () {
 
       t.agent.addRemoteConfig(rcConfig)
     })
+
+    it('should adhere to individual probes sample rate', function (done) {
+      const rcConfig1 = t.breakpoints[0].generateRemoteConfig({ sampling: { snapshotsPerSecond: 1 } })
+      const rcConfig2 = t.breakpoints[1].generateRemoteConfig({ sampling: { snapshotsPerSecond: 1 } })
+      const state = {
+        [rcConfig1.config.id]: {
+          payloadsReceived: 0,
+          tiggerBreakpointContinuously () {
+            t.axios.get(t.breakpoints[0].url).catch(done)
+            this.timer = setTimeout(this.tiggerBreakpointContinuously.bind(this), 10)
+          }
+        },
+        [rcConfig2.config.id]: {
+          payloadsReceived: 0,
+          tiggerBreakpointContinuously () {
+            t.axios.get(t.breakpoints[1].url).catch(done)
+            this.timer = setTimeout(this.tiggerBreakpointContinuously.bind(this), 10)
+          }
+        }
+      }
+
+      t.agent.on('debugger-diagnostics', ({ payload }) => {
+        const { probeId, status } = payload.debugger.diagnostics
+        if (status === 'INSTALLED') state[probeId].tiggerBreakpointContinuously()
+      })
+
+      t.agent.on('debugger-input', ({ payload }) => {
+        const _state = state[payload['debugger.snapshot'].probe.id]
+        _state.payloadsReceived++
+        if (_state.payloadsReceived === 1) {
+          _state.start = Date.now()
+        } else if (_state.payloadsReceived === 2) {
+          const duration = Date.now() - _state.start
+          clearTimeout(_state.timer)
+
+          // Allow for a variance of -5/+50ms (time will tell if this is enough)
+          assert.isAbove(duration, 995)
+          assert.isBelow(duration, 1050)
+
+          // Wait at least a full sampling period, to see if we get any more payloads
+          _state.timer = setTimeout(doneWhenCalledTwice, 1250)
+        } else {
+          clearTimeout(_state.timer)
+          done(new Error('Too many payloads received!'))
+        }
+      })
+
+      t.agent.addRemoteConfig(rcConfig1)
+      t.agent.addRemoteConfig(rcConfig2)
+
+      function doneWhenCalledTwice () {
+        if (doneWhenCalledTwice.calledOnce) return done()
+        doneWhenCalledTwice.calledOnce = true
+      }
+    })
   })
 
   describe('race conditions', function () {

integration-tests/debugger/target-app/basic.js

@@ -5,8 +5,12 @@ const Fastify = require('fastify')
 
 const fastify = Fastify()
 
-fastify.get('/:name', function handler (request) {
-  return { hello: request.params.name } // BREAKPOINT: /foo
+fastify.get('/foo/:name', function fooHandler (request) {
+  return { hello: request.params.name } // BREAKPOINT: /foo/bar
+})
+
+fastify.get('/bar/:name', function barHandler (request) {
+  return { hello: request.params.name } // BREAKPOINT: /bar/baz
 })
 
 fastify.listen({ port: process.env.APP_PORT }, (err) => {

integration-tests/debugger/utils.js

@@ -20,28 +20,43 @@ module.exports = {
 
 function setup () {
   let sandbox, cwd, appPort
-  const breakpoint = getBreakpointInfo(1) // `1` to disregard the `setup` function
+  const breakpoints = getBreakpointInfo(1) // `1` to disregard the `setup` function
   const t = {
-    breakpoint,
+    breakpoint: breakpoints[0],
+    breakpoints,
+
     axios: null,
     appFile: null,
     agent: null,
+
+    // Default to the first breakpoint in the file (normally there's only one)
     rcConfig: null,
-    triggerBreakpoint,
-    generateRemoteConfig,
-    generateProbeConfig
+    triggerBreakpoint: triggerBreakpoint.bind(null, breakpoints[0].url),
+    generateRemoteConfig: generateRemoteConfig.bind(null, breakpoints[0]),
+    generateProbeConfig: generateProbeConfig.bind(null, breakpoints[0])
   }
 
-  function triggerBreakpoint () {
+  // Allow specific access to each breakpoint
+  for (let i = 0; i < breakpoints.length; i++) {
+    t.breakpoints[i] = {
+      rcConfig: null,
+      triggerBreakpoint: triggerBreakpoint.bind(null, breakpoints[i].url),
+      generateRemoteConfig: generateRemoteConfig.bind(null, breakpoints[i]),
+      generateProbeConfig: generateProbeConfig.bind(null, breakpoints[i]),
+      ...breakpoints[i]
+    }
+  }
+
+  function triggerBreakpoint (url) {
     // Trigger the breakpoint once probe is successfully installed
     t.agent.on('debugger-diagnostics', ({ payload }) => {
       if (payload.debugger.diagnostics.status === 'INSTALLED') {
-        t.axios.get(breakpoint.url)
+        t.axios.get(url)
       }
     })
   }
 
-  function generateRemoteConfig (overrides = {}) {
+  function generateRemoteConfig (breakpoint, overrides = {}) {
     overrides.id = overrides.id || randomUUID()
     return {
       product: 'LIVE_DEBUGGING',
@@ -54,15 +69,19 @@ function setup () {
     sandbox = await createSandbox(['fastify']) // TODO: Make this dynamic
     cwd = sandbox.folder
     // The sandbox uses the `integration-tests` folder as its root
-    t.appFile = join(cwd, 'debugger', breakpoint.file)
+    t.appFile = join(cwd, 'debugger', breakpoints[0].file)
   })
 
   after(async function () {
     await sandbox.remove()
   })
 
   beforeEach(async function () {
-    t.rcConfig = generateRemoteConfig(breakpoint)
+    // Default to the first breakpoint in the file (normally there's only one)
+    t.rcConfig = generateRemoteConfig(breakpoints[0])
+    // Allow specific access to each breakpoint
+    t.breakpoints.forEach((breakpoint) => { breakpoint.rcConfig = generateRemoteConfig(breakpoint) })
+
     appPort = await getPort()
     t.agent = await new FakeAgent().start()
     t.proc = await spawnProc(t.appFile, {
@@ -96,16 +115,19 @@ function getBreakpointInfo (stackIndex = 0) {
     .slice(0, -1)
     .split(':')[0]
 
-  // Then, find the corresponding file in which the breakpoint exists
+  // Then, find the corresponding file in which the breakpoint(s) exists
   const file = join('target-app', basename(testFile).replace('.spec', ''))
 
-  // Finally, find the line number of the breakpoint
+  // Finally, find the line number(s) of the breakpoint(s)
   const lines = readFileSync(join(__dirname, file), 'utf8').split('\n')
+  const result = []
   for (let i = 0; i < lines.length; i++) {
     const index = lines[i].indexOf(BREAKPOINT_TOKEN)
     if (index !== -1) {
       const url = lines[i].slice(index + BREAKPOINT_TOKEN.length + 1).trim()
-      return { file, line: i + 1, url }
+      result.push({ file, line: i + 1, url })
     }
   }
+
+  return result
 }