@tailchi/fetch

Browser fetch instrumentation for tailchi. Automatically traces all fetch requests.

Installation

npm install @tailchi/core @tailchi/fetch

Usage

import { configureHounddog } from '@tailchi/core';
import { enableHoundFetch } from '@tailchi/fetch';

// Configure core first
configureHounddog({
  service: 'web',
  sink: {
    kind: 'http',
    endpoint: 'http://localhost:4000/__hound/events',
  },
});

// Patch global fetch
enableHoundFetch();

// All fetch calls are now instrumented
await fetch('/api/users');

Events Emitted

For each fetch request:

• http.sent - Request initiated
• http.response - Response received (with status and duration)

Flow Propagation

The instrumented fetch automatically:

• Propagates flow IDs via the x-hound-flow header
• Creates a new flow if none exists
• Skips internal /__hound/events requests

Example Output

│ 📤 out.http.sent url=http://localhost:4000/api/users +0ms
│ 📥 in.http.response 200 (45ms) url=http://localhost:4000/api/users +45ms