feat: Add continuous profiling support (Sample Format V2) (#1202)

## Summary

Add support for continuous profiling (Profiling V2) while maintaining
backward compatibility with transaction-based profiling (V1).

## Changes

- Add `SentryProfileV2ChunkEvent` type for `profile_chunk` envelope
items
- Process and merge V2 chunks by `profiler_id`
- Link profiles to traces via `contexts.profile.profiler_id`
- Unify V1 and V2 profiles in `profilesByTraceId` storage
- Handle late-arriving chunks with re-grafting
- Add test fixtures for manual UI testing

## Testing

```bash
pnpm dev

# In another terminal:
cd packages/spotlight
node _fixtures/send_to_sidecar.cjs _fixtures/continuous_profiling/
```

Then open Spotlight UI, navigate to the trace, and verify:
1. The "Profile" tab appears in trace details
2. Profile spans are grafted into the trace tree

<img width="2200" height="1744" alt="image"
src="https://github.com/user-attachments/assets/c0eb7946-df8f-42cb-a240-b38736966a54"
/>


Closes #567

Author: BYK

.changeset/continuous-profiling-support.md

@@ -0,0 +1,6 @@
+---
+"@spotlightjs/spotlight": minor
+---
+
+Add support for continuous profiling (Profiling V2)
+

packages/spotlight/_fixtures/continuous_profiling/README.md

@@ -0,0 +1,66 @@
+# Continuous Profiling Test Fixtures
+
+This directory contains test fixtures for continuous profiling (Sample Format V2).
+
+## Files
+
+| File | Description |
+|------|-------------|
+| `profile_chunk_1.txt` | First profile chunk - app launch & Sentry setup samples |
+| `profile_chunk_2.txt` | Second profile chunk - view loading & network samples |
+| `transaction.txt` | Transaction linked to profiles via `contexts.profile.profiler_id` |
+
+## Usage
+
+Send all fixtures to the sidecar for manual testing:
+
+```bash
+# From the spotlight package directory
+cd packages/spotlight
+
+# Send all continuous profiling fixtures
+node _fixtures/send_to_sidecar.cjs _fixtures/continuous_profiling/
+```
+
+Or send individual files:
+
+```bash
+node _fixtures/send_to_sidecar.cjs _fixtures/continuous_profiling/profile_chunk_1.txt
+node _fixtures/send_to_sidecar.cjs _fixtures/continuous_profiling/profile_chunk_2.txt
+node _fixtures/send_to_sidecar.cjs _fixtures/continuous_profiling/transaction.txt
+```
+
+## Linking
+
+The profile chunks and transaction are linked via:
+
+| Field | Value |
+|-------|-------|
+| `profiler_id` | `71bba98d90b545c39f2ae73f702d7ef4` |
+| `trace_id` | `f1e2d3c4b5a6978012345678901234ab` |
+| `thread.id` | `259` (main thread) |
+
+## Profile Chunk Contents
+
+### Chunk 1 - App Launch (timestamps ~1724777211.50 - 1724777211.56)
+
+Call stack progression:
+- `_main`
+- `UIApplicationMain` -> `_main`
+- `-[AppDelegate application:didFinishLaunchingWithOptions:]` -> `UIApplicationMain` -> `_main`
+- `-[AppDelegate setupSentry]` -> ... (deepest)
+
+### Chunk 2 - View Loading (timestamps ~1724777211.57 - 1724777211.63)
+
+Call stack progression:
+- `-[ViewController viewDidLoad]`
+- `-[ViewController setupUI]` -> `viewDidLoad`
+- `-[ViewController loadData]` -> `setupUI` -> `viewDidLoad`
+- `-[NetworkManager fetchItems]` -> ... (deepest)
+
+## Transaction Spans
+
+The transaction includes the following spans:
+- `app.start.cold` - Cold App Start (60ms)
+- `ui.load` - ViewController.viewDidLoad (60ms)
+  - `http.client` - GET /api/items (40ms)

packages/spotlight/_fixtures/continuous_profiling/profile_chunk_1.txt

@@ -0,0 +1,3 @@
+{"event_id":"3e11a5c9831f4e49939c0a81944ea2cb","sent_at":"2024-08-27T15:00:11.503779Z","sdk":{"name":"sentry.cocoa","version":"8.36.0"}}
+{"type":"profile_chunk","length":1671}
+{"type":"profile_chunk","version":"2","profiler_id":"71bba98d90b545c39f2ae73f702d7ef4","chunk_id":"3e11a5c9831f4e49939c0a81944ea2cb","platform":"cocoa","release":"io.sentry.sample.iOS-Swift@8.36.0+1","environment":"simulator","client_sdk":{"name":"sentry.cocoa","version":"8.36.0"},"debug_meta":{"images":[{"debug_id":"5819FF25-01CB-3D32-B84F-0634B37D3BBC","image_addr":"0x00000001023a8000","type":"macho","image_size":16384,"code_file":"/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS17.2.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libLogRedirect.dylib"}]},"profile":{"samples":[{"timestamp":1724770811.503,"stack_id":0,"thread_id":"259"},{"timestamp":1724770811.513,"stack_id":1,"thread_id":"259"},{"timestamp":1724770811.523,"stack_id":2,"thread_id":"259"},{"timestamp":1724770811.533,"stack_id":3,"thread_id":"259"},{"timestamp":1724770811.543,"stack_id":2,"thread_id":"259"},{"timestamp":1724770811.553,"stack_id":1,"thread_id":"259"},{"timestamp":1724770811.563,"stack_id":0,"thread_id":"259"}],"stacks":[[0],[1,0],[2,1,0],[3,2,1,0]],"frames":[{"instruction_addr":"0x000000010232d144","function":"_main","filename":"main.m","lineno":14,"in_app":true},{"instruction_addr":"0x000000010232d200","function":"UIApplicationMain","module":"UIKit","in_app":false},{"instruction_addr":"0x000000010232d300","function":"-[AppDelegate application:didFinishLaunchingWithOptions:]","filename":"AppDelegate.swift","lineno":15,"in_app":true},{"instruction_addr":"0x000000010232d400","function":"-[AppDelegate setupSentry]","filename":"AppDelegate.swift","lineno":25,"in_app":true}],"thread_metadata":{"259":{"name":"main","priority":31}}}}

packages/spotlight/_fixtures/continuous_profiling/profile_chunk_2.txt

@@ -0,0 +1,3 @@
+{"event_id":"abc123def456789012345678901234cd","sent_at":"2024-08-27T15:00:11.603779Z","sdk":{"name":"sentry.cocoa","version":"8.36.0"}}
+{"type":"profile_chunk","length":1432}
+{"type":"profile_chunk","version":"2","profiler_id":"71bba98d90b545c39f2ae73f702d7ef4","chunk_id":"abc123def456789012345678901234cd","platform":"cocoa","release":"io.sentry.sample.iOS-Swift@8.36.0+1","environment":"simulator","client_sdk":{"name":"sentry.cocoa","version":"8.36.0"},"profile":{"samples":[{"timestamp":1724770811.573,"stack_id":0,"thread_id":"259"},{"timestamp":1724770811.583,"stack_id":1,"thread_id":"259"},{"timestamp":1724770811.593,"stack_id":2,"thread_id":"259"},{"timestamp":1724770811.603,"stack_id":3,"thread_id":"259"},{"timestamp":1724770811.613,"stack_id":2,"thread_id":"259"},{"timestamp":1724770811.623,"stack_id":1,"thread_id":"259"},{"timestamp":1724770811.633,"stack_id":0,"thread_id":"259"}],"stacks":[[0],[1,0],[2,1,0],[3,2,1,0]],"frames":[{"instruction_addr":"0x000000010232e100","function":"-[ViewController viewDidLoad]","filename":"ViewController.swift","lineno":20,"in_app":true},{"instruction_addr":"0x000000010232e200","function":"-[ViewController setupUI]","filename":"ViewController.swift","lineno":35,"in_app":true},{"instruction_addr":"0x000000010232e300","function":"-[ViewController loadData]","filename":"ViewController.swift","lineno":50,"in_app":true},{"instruction_addr":"0x000000010232e400","function":"-[NetworkManager fetchItems]","filename":"NetworkManager.swift","lineno":15,"in_app":true}],"thread_metadata":{"259":{"name":"main","priority":31}}}}

packages/spotlight/_fixtures/continuous_profiling/transaction.txt

@@ -0,0 +1,3 @@
+{"event_id":"txn_continuous_profile_123abc","sent_at":"2024-08-27T15:00:11.700000Z","trace":{"environment":"simulator","public_key":"abc123def456","trace_id":"f1e2d3c4b5a6978012345678901234ab"},"sdk":{"name":"sentry.cocoa","version":"8.36.0"}}
+{"type":"transaction","length":2262}
+{"type":"transaction","transaction":"iOS App Launch","transaction_info":{"source":"custom"},"contexts":{"trace":{"trace_id":"f1e2d3c4b5a6978012345678901234ab","span_id":"abc123def4567890","op":"app.launch","description":"iOS Application Launch","status":"ok","data":{"thread.id":"259","thread.name":"main"}},"profile":{"profiler_id":"71bba98d90b545c39f2ae73f702d7ef4"},"device":{"family":"iPhone","model":"iPhone14,2","arch":"arm64","simulator":true},"os":{"name":"iOS","version":"17.2"},"app":{"app_name":"iOS-Swift","app_version":"8.36.0","app_build":"1"}},"tags":{"environment":"simulator"},"timestamp":"2024-08-27T15:00:11.640000Z","start_timestamp":"2024-08-27T15:00:11.500000Z","spans":[{"trace_id":"f1e2d3c4b5a6978012345678901234ab","span_id":"span1234567890ab","parent_span_id":"abc123def4567890","op":"app.start.cold","description":"Cold App Start","start_timestamp":"2024-08-27T15:00:11.503779Z","timestamp":"2024-08-27T15:00:11.563779Z","status":"ok","data":{"thread.id":"259","thread.name":"main"}},{"trace_id":"f1e2d3c4b5a6978012345678901234ab","span_id":"span2345678901bc","parent_span_id":"abc123def4567890","op":"ui.load","description":"ViewController.viewDidLoad","start_timestamp":"2024-08-27T15:00:11.573779Z","timestamp":"2024-08-27T15:00:11.633779Z","status":"ok","data":{"thread.id":"259","thread.name":"main"}},{"trace_id":"f1e2d3c4b5a6978012345678901234ab","span_id":"span3456789012cd","parent_span_id":"span2345678901bc","op":"http.client","description":"GET /api/items","start_timestamp":"2024-08-27T15:00:11.583779Z","timestamp":"2024-08-27T15:00:11.623779Z","status":"ok","data":{"http.method":"GET","http.url":"https://api.example.com/api/items","http.status_code":200,"thread.id":"259"}}],"measurements":{"app_start_cold":{"value":140,"unit":"millisecond"},"frames_total":{"value":120,"unit":"none"},"frames_slow":{"value":2,"unit":"none"},"frames_frozen":{"value":0,"unit":"none"}},"event_id":"txn_continuous_profile_123abc","platform":"cocoa","release":"io.sentry.sample.iOS-Swift@8.36.0+1","environment":"simulator","sdk":{"name":"sentry.cocoa","version":"8.36.0","packages":[{"name":"cocoapods:sentry-cocoa","version":"8.36.0"}],"integrations":["AutoBreadcrumbTracking","AutoSessionTracking","Crash","Performance","Profiling"]}}

packages/spotlight/src/server/formatters/md/__tests__/test_envelopes.ts

@@ -455,3 +455,216 @@ export const envelopeSecondTransactionEvent = {
     version: "9.42.1",
   },
 };
+
+// V1 Profile Event (transaction-based profiling)
+export const envelopeProfileV1Event = {
+  type: "profile" as const,
+  version: "1" as const,
+  event_id: "profile1234567890abcdef1234567890ab",
+  timestamp: 1754524400.5,
+  platform: "python",
+  device: {
+    architecture: "x86_64",
+    is_emulator: false,
+    locale: "en-US",
+    manufacturer: "Apple",
+    model: "MacBookPro18,3",
+  },
+  os: {
+    name: "macOS",
+    version: "14.0",
+    build_number: "23A344",
+  },
+  transactions: [
+    {
+      name: "/api/users",
+      id: "txn123456789abcdef",
+      trace_id: "71a8c5e41ae1044dee67f50a07538fe7",
+      active_thread_id: "1",
+      relative_start_ns: "0",
+      relative_end_ns: "100000000",
+    },
+  ],
+  profile: {
+    samples: [
+      { elapsed_since_start_ns: "0", stack_id: 0, thread_id: "1" },
+      { elapsed_since_start_ns: "10000000", stack_id: 1, thread_id: "1" },
+      { elapsed_since_start_ns: "20000000", stack_id: 2, thread_id: "1" },
+      { elapsed_since_start_ns: "30000000", stack_id: 1, thread_id: "1" },
+      { elapsed_since_start_ns: "40000000", stack_id: 0, thread_id: "1" },
+    ],
+    stacks: [
+      [0], // main
+      [1, 0], // handle_request -> main
+      [2, 1, 0], // query_database -> handle_request -> main
+    ],
+    frames: [
+      { function: "main", filename: "app.py", lineno: 10, in_app: true },
+      { function: "handle_request", filename: "views.py", lineno: 25, in_app: true },
+      { function: "query_database", filename: "db.py", lineno: 50, in_app: true },
+    ],
+    thread_metadata: {
+      "1": { name: "MainThread", priority: 5 },
+    },
+  },
+};
+
+// V2 Profile Chunk Event (continuous profiling)
+export const envelopeProfileV2ChunkEvent = {
+  type: "profile_chunk" as const,
+  version: "2" as const,
+  profiler_id: "71bba98d90b545c39f2ae73f702d7ef4",
+  chunk_id: "3e11a5c9831f4e49939c0a81944ea2cb",
+  platform: "cocoa",
+  release: "io.sentry.sample.iOS-Swift@8.36.0+1",
+  environment: "simulator",
+  client_sdk: {
+    name: "sentry.cocoa",
+    version: "8.36.0",
+  },
+  debug_meta: {
+    images: [
+      {
+        debug_id: "5819FF25-01CB-3D32-B84F-0634B37D3BBC",
+        image_addr: "0x00000001023a8000",
+        type: "macho",
+        image_size: 16384,
+        code_file:
+          "/Library/Developer/CoreSimulator/Volumes/iOS_21C62/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 17.2.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libLogRedirect.dylib",
+      },
+    ],
+  },
+  measurements: {
+    frozen_frame_renders: {
+      unit: "nanosecond",
+      values: [{ timestamp: 1724777211.6403089, value: 16000000 }],
+    },
+  },
+  profile: {
+    samples: [
+      { timestamp: 1724777211.5037799, stack_id: 0, thread_id: "259" },
+      { timestamp: 1724777211.5137799, stack_id: 1, thread_id: "259" },
+      { timestamp: 1724777211.5237799, stack_id: 2, thread_id: "259" },
+      { timestamp: 1724777211.5337799, stack_id: 1, thread_id: "259" },
+      { timestamp: 1724777211.5437799, stack_id: 0, thread_id: "259" },
+    ],
+    stacks: [
+      [0], // _main
+      [1, 0], // UIApplicationMain -> _main
+      [2, 1, 0], // -[AppDelegate application:didFinishLaunchingWithOptions:] -> UIApplicationMain -> _main
+    ],
+    frames: [
+      {
+        instruction_addr: "0x000000010232d144",
+        function: "_main",
+        filename: "main.m",
+        in_app: true,
+      },
+      {
+        instruction_addr: "0x000000010232d200",
+        function: "UIApplicationMain",
+        module: "UIKit",
+        in_app: false,
+      },
+      {
+        instruction_addr: "0x000000010232d300",
+        function: "-[AppDelegate application:didFinishLaunchingWithOptions:]",
+        filename: "AppDelegate.swift",
+        lineno: 15,
+        in_app: true,
+      },
+    ],
+    thread_metadata: {
+      "259": { name: "main", priority: 31 },
+    },
+  },
+};
+
+// Second V2 chunk for the same profiler session (for testing chunk merging)
+export const envelopeProfileV2ChunkEvent2 = {
+  type: "profile_chunk" as const,
+  version: "2" as const,
+  profiler_id: "71bba98d90b545c39f2ae73f702d7ef4", // Same profiler_id
+  chunk_id: "abc123def456789012345678901234cd", // Different chunk_id
+  platform: "cocoa",
+  release: "io.sentry.sample.iOS-Swift@8.36.0+1",
+  environment: "simulator",
+  client_sdk: {
+    name: "sentry.cocoa",
+    version: "8.36.0",
+  },
+  profile: {
+    samples: [
+      { timestamp: 1724777211.553, stack_id: 0, thread_id: "259" },
+      { timestamp: 1724777211.563, stack_id: 1, thread_id: "259" },
+      { timestamp: 1724777211.573, stack_id: 0, thread_id: "259" },
+    ],
+    stacks: [
+      [0], // viewDidLoad
+      [1, 0], // loadData -> viewDidLoad
+    ],
+    frames: [
+      {
+        instruction_addr: "0x000000010232e100",
+        function: "-[ViewController viewDidLoad]",
+        filename: "ViewController.swift",
+        lineno: 20,
+        in_app: true,
+      },
+      {
+        instruction_addr: "0x000000010232e200",
+        function: "-[ViewController loadData]",
+        filename: "ViewController.swift",
+        lineno: 45,
+        in_app: true,
+      },
+    ],
+    thread_metadata: {
+      "259": { name: "main", priority: 31 },
+    },
+  },
+};
+
+// Transaction with profiler_id context (for V2 profile linking)
+export const envelopeTransactionWithProfilerContext = {
+  event_id: "txn_with_profiler_123",
+  type: "transaction",
+  transaction: "/ios/app/launch",
+  timestamp: 1724777211.6,
+  start_timestamp: 1724777211.5,
+  platform: "cocoa",
+  contexts: {
+    trace: {
+      trace_id: "f1e2d3c4b5a6978012345678901234ab",
+      span_id: "abc123def4567890",
+      parent_span_id: undefined,
+      data: {
+        "thread.id": "259",
+        "thread.name": "main",
+      },
+    },
+    profile: {
+      profiler_id: "71bba98d90b545c39f2ae73f702d7ef4", // Links to V2 profile chunks
+    },
+  },
+  spans: [
+    {
+      span_id: "span1234567890ab",
+      parent_span_id: "abc123def4567890",
+      trace_id: "f1e2d3c4b5a6978012345678901234ab",
+      op: "app.start",
+      description: "Application Launch",
+      start_timestamp: 1724777211.51,
+      timestamp: 1724777211.55,
+      duration: 40,
+      status: "ok",
+      data: {
+        "thread.id": "259",
+      },
+    },
+  ],
+  sdk: {
+    name: "sentry.cocoa",
+    version: "8.36.0",
+  },
+};

packages/spotlight/src/server/parser/types.ts

@@ -223,6 +223,61 @@ export type SentryProfileV1Event = CommonEventAttrs & {
   profile: SentryProfile;
 };
 
+// V2 Profile (Continuous Profiling) Types
+export type ProfileV2Sample = {
+  timestamp: number; // Unix timestamp in seconds with microseconds precision
+  stack_id: number;
+  thread_id: string;
+};
+
+export type ProfileV2MeasurementValue = {
+  timestamp: number;
+  value: number;
+};
+
+export type ProfileV2Measurement = {
+  unit: string;
+  values: ProfileV2MeasurementValue[];
+};
+
+export type SentryProfileV2 = {
+  samples: ProfileV2Sample[];
+  stacks: number[][];
+  frames: EventFrame[];
+  thread_metadata: Record<
+    string,
+    {
+      name?: string;
+      priority?: number;
+    }
+  >;
+};
+
+export type SentryProfileV2ChunkEvent = {
+  type: "profile_chunk";
+  version: "2";
+  profiler_id: string; // Links chunks from same profiler session
+  chunk_id: string; // Unique ID for this chunk
+  platform: string;
+  release?: string;
+  environment?: string;
+  client_sdk?: {
+    name: string;
+    version: string;
+  };
+  debug_meta?: {
+    images?: Array<{
+      debug_id?: string;
+      image_addr?: string;
+      type?: string;
+      image_size?: number;
+      code_file?: string;
+    }>;
+  };
+  measurements?: Record<string, ProfileV2Measurement>;
+  profile: SentryProfileV2;
+};
+
 export type SentryLogEventItem = SerializedLog & {
   id: string; // Need to have a unique id for each log
   severity_number: number;
@@ -234,4 +289,9 @@ export type SentryLogEvent = CommonEventAttrs & {
   items: Array<SentryLogEventItem>;
 };
 
-export type SentryEvent = SentryErrorEvent | SentryTransactionEvent | SentryProfileV1Event | SentryLogEvent;
+export type SentryEvent =
+  | SentryErrorEvent
+  | SentryTransactionEvent
+  | SentryProfileV1Event
+  | SentryProfileV2ChunkEvent
+  | SentryLogEvent;

packages/spotlight/src/ui/lib/isElectron.ts

@@ -4,4 +4,3 @@
  * Uses typeof check to safely handle undefined without throwing.
  */
 export const IS_ELECTRON = typeof __IS_ELECTRON__ !== "undefined" && __IS_ELECTRON__;
-