sentry-hello-world

Sentry Hello World

Overview

Send your first test events to Sentry — a captured message, a captured exception, and a fully-enriched error with user context, tags, and breadcrumbs — then verify each one appears in the Sentry dashboard. This skill covers both Node.js (@sentry/node) and Python (sentry-sdk).

Prerequisites

• Completed sentry-install-auth setup (SDK installed, DSN configured)
• Valid SENTRY_DSN in environment variables
• instrument.mjs loaded before app code (Node.js) or sentry_sdk.init() called (Python)
• Network access to *.ingest.sentry.io

Instructions

Step 1 — Verify the SDK Is Active

Before sending test events, confirm the SDK initialized correctly. If getClient() returns undefined, the SDK was never initialized — go back to sentry-install-auth.

TypeScript (Node.js):

import * as Sentry from '@sentry/node';

const client = Sentry.getClient();
if (!client) {
  console.error('Sentry SDK not initialized. Ensure instrument.mjs is loaded first.');
  console.error('Run with: node --import ./instrument.mjs your-script.mjs');
  process.exit(1);
}
console.log('Sentry SDK active — DSN configured');

Python:

import sentry_sdk

client = sentry_sdk.Hub.current.client
if client is None or client.dsn is None:
    print("Sentry SDK not initialized. Call sentry_sdk.init() first.")
    exit(1)
print("Sentry SDK active — DSN configured")

Step 2 — Capture a Test Message

captureMessage sends an informational event without a stack trace. Use it to verify basic connectivity between your app and Sentry.

TypeScript:

import * as Sentry from '@sentry/node';

// captureMessage returns the event ID (a 32-char hex string)
const eventId = Sentry.captureMessage('Hello Sentry! SDK verification test.', 'info');
console.log(`Message sent — Event ID: ${eventId}`);

// Also test 'warning' level — appears with yellow indicator in dashboard
Sentry.captureMessage('Warning-level test message', 'warning');

// IMPORTANT: flush before process exits or events may be lost
await Sentry.flush(2000);

Python:

import sentry_sdk

event_id = sentry_sdk.capture_message("Hello Sentry! SDK verification test.", level="info")
print(f"Message sent — Event ID: {event_id}")

sentry_sdk.capture_message("Warning-level test message", level="warning")

# Flush to ensure delivery before process exits
sentry_sdk.flush()

Step 3 — Capture a Test Exception

captureException sends a full error with stack trace. Always pass an actual Error object (not a string) so Sentry generates a proper stack trace.

TypeScript:

import * as Sentry from '@sentry/node';

try {
  throw new Error('Hello Sentry! This is a test exception.');
} catch (error) {
  const eventId = Sentry.captureException(error);
  console.log(`Exception sent — Event ID: ${eventId}`);
}

await Sentry.flush(2000);

Python:

import sentry_sdk

try:
    raise ValueError("Hello Sentry! This is a test exception.")
except Exception as e:
    event_id = sentry_sdk.capture_exception(e)
    print(f"Exception sent — Event ID: {event_id}")

sentry_sdk.flush()

Step 4 — Add User Context and Tags

Enrich events with identity and metadata so you can filter and search in the dashboard. setUser attaches to all subsequent events in the current scope. setTag creates indexed, searchable key-value pairs.

TypeScript:

import * as Sentry from '@sentry/node';

// Attach user identity — appears in the "User" section of every event
Sentry.setUser({
  id: 'test-user-001',
  email: 'dev@example.com',
  username: 'developer',
});

// Tags are indexed and searchable — use for filtering in Issues view
Sentry.setTag('test_run', 'hello-world');
Sentry.setTag('team', 'platform');

// setContext adds structured data (not indexed, but visible in event detail)
Sentry.setContext('test_metadata', {
  ran_at: new Date().toISOString(),
  node_version: process.version,
  purpose: 'SDK verification',
});

// This event will carry user, tags, and context
Sentry.captureMessage('Test event with full context attached', 'info');

await Sentry.flush(2000);

Python:

import sentry_sdk
from datetime import datetime, timezone
import sys

sentry_sdk.set_user({"id": "test-user-001", "email": "dev@example.com", "username": "developer"})

sentry_sdk.set_tag("test_run", "hello-world")
sentry_sdk.set_tag("team", "platform")

sentry_sdk.set_context("test_metadata", {
    "ran_at": datetime.now(timezone.utc).isoformat(),
    "python_version": sys.version,
    "purpose": "SDK verification",
})

sentry_sdk.capture_message("Test event with full context attached", level="info")

sentry_sdk.flush()

Step 5 — Add Breadcrumbs

Breadcrumbs record a trail of events leading up to an error. They appear in the event detail view, giving you the chronological context of what happened before the crash.

TypeScript:

import * as Sentry from '@sentry/node';

Sentry.addBreadcrumb({
  category: 'auth',
  message: 'User authenticated successfully',
  level: 'info',
});

Sentry.addBreadcrumb({
  category: 'http',
  message: 'GET /api/users returned 200',
  level: 'info',
  data: { status_code: 200, url: '/api/users', method: 'GET' },
});

Sentry.addBreadcrumb({
  category: 'ui',
  message: 'User clicked "Submit Order" button',
  level: 'info',
});

// This exception will carry all three breadcrumbs above
try {
  throw new Error('Order processing failed — breadcrumb trail attached');
} catch (error) {
  Sentry.captureException(error);
}

await Sentry.flush(2000);

Python:

import sentry_sdk

sentry_sdk.add_breadcrumb(category="auth", message="User authenticated successfully", level="info")
sentry_sdk.add_breadcrumb(category="http", message="GET /api/users returned 200", level="info",
                          data={"status_code": 200, "url": "/api/users"})
sentry_sdk.add_breadcrumb(category="ui", message="User clicked Submit Order button", level="info")

try:
    raise RuntimeError("Order processing failed — breadcrumb trail attached")
except Exception as e:
    sentry_sdk.capture_exception(e)

sentry_sdk.flush()

Step 6 — Verify in the Sentry Dashboard

1. Open https://sentry.io and select your project
2. Navigate to the Issues tab — test errors appear as grouped issues
3. Click an issue to inspect the event detail:
   • Stack Trace — file path, line number, and surrounding code context
   • User section — id, email, username from setUser()
   • Tags sidebar — test_run: hello-world, team: platform
   • Breadcrumbs tab — chronological trail of events before the error
   • Additional Data — custom context from setContext()
4. Use the search bar to filter: test_run:hello-world narrows to your test events
5. Confirm Environment matches your SENTRY_ENVIRONMENT value
6. Confirm Release matches your SENTRY_RELEASE value (if set)
7. Delete test issues when done: select issues > Resolve or Delete

Examples

Complete Verification Script (TypeScript)

Save as test-sentry.mjs and run with node --import ./instrument.mjs test-sentry.mjs to exercise all capabilities at once.

// Run with: node --import ./instrument.mjs test-sentry.mjs
import * as Sentry from '@sentry/node';

async function main() {
  console.log('--- Sentry Hello World Verification ---\n');

  // 1. Verify SDK
  const client = Sentry.getClient();
  if (!client) {
    console.error('ERROR: Sentry SDK not initialized.');
    console.error('Run with: node --import ./instrument.mjs test-sentry.mjs');
    process.exit(1);
  }
  console.log('[OK] Sentry SDK active');

  // 2. Set user context and tags
  Sentry.setUser({ id: 'test-001', email: 'dev@example.com', username: 'developer' });
  Sentry.setTag('test_run', 'hello-world');
  Sentry.setTag('environment', process.env.SENTRY_ENVIRONMENT || 'test');
  console.log('[OK] User context and tags set');

  // 3. Capture a message
  const msgId = Sentry.captureMessage('Hello Sentry — SDK verification', 'info');
  console.log(`[OK] Message captured — Event ID: ${msgId}`);

  // 4. Capture an exception with breadcrumbs
  Sentry.addBreadcrumb({ category: 'test', message: 'Starting verification script', level: 'info' });
  Sentry.addBreadcrumb({ category: 'test', message: 'About to throw test error', level: 'warning' });

  try {
    throw new Error('Hello Sentry! Verification test exception.');
  } catch (error) {
    const errId = Sentry.captureException(error);
    console.log(`[OK] Exception captured — Event ID: ${errId}`);
  }

  // 5. Flush and report
  await Sentry.flush(5000);
  console.log('\n[DONE] All events flushed — check your Sentry dashboard at https://sentry.io');
  console.log('Navigate to Issues tab, filter by tag: test_run:hello-world');
}

main();

Complete Verification Script (Python)

Save as test_sentry.py and run with python test_sentry.py (after calling sentry_sdk.init() in your setup).

# Run with: python test_sentry.py (after sentry_sdk.init() in your setup)
import sentry_sdk
import os
import sys

def main():
    print("--- Sentry Hello World Verification ---\n")

    # 1. Verify SDK
    client = sentry_sdk.Hub.current.client
    if client is None or client.dsn is None:
        print("ERROR: Sentry SDK not initialized.")
        print("Ensure sentry_sdk.init(dsn=...) is called before this script.")
        sys.exit(1)
    print("[OK] Sentry SDK active")

    # 2. Set user context and tags
    sentry_sdk.set_user({"id": "test-001", "email": "dev@example.com", "username": "developer"})
    sentry_sdk.set_tag("test_run", "hello-world")
    sentry_sdk.set_tag("environment", os.environ.get("SENTRY_ENVIRONMENT", "test"))
    print("[OK] User context and tags set")

    # 3. Capture a message
    msg_id = sentry_sdk.capture_message("Hello Sentry — SDK verification", level="info")
    print(f"[OK] Message captured — Event ID: {msg_id}")

    # 4. Capture an exception with breadcrumbs
    sentry_sdk.add_breadcrumb(category="test", message="Starting verification script", level="info")
    sentry_sdk.add_breadcrumb(category="test", message="About to throw test error", level="warning")

    try:
        raise ValueError("Hello Sentry! Verification test exception.")
    except Exception as e:
        err_id = sentry_sdk.capture_exception(e)
        print(f"[OK] Exception captured — Event ID: {err_id}")

    # 5. Flush and report
    sentry_sdk.flush()
    print("\n[DONE] All events flushed — check your Sentry dashboard at https://sentry.io")
    print("Navigate to Issues tab, filter by tag: test_run:hello-world")

if __name__ == "__main__":
    main()

Output

• Test message visible in Sentry dashboard Issues tab within 30 seconds
• Test exception visible with full stack trace pointing to correct file and line
• User context (id, email, username) attached to every event
• Tags (test_run, team) searchable in the Issues sidebar filter
• Breadcrumb trail visible in event detail, showing events leading up to the error
• Custom context visible under "Additional Data" in event detail
• Event IDs printed to console for cross-referencing with dashboard

Error Handling

Error	Cause	Solution
Event not appearing in dashboard	DSN misconfigured or env var not loaded	Run echo $SENTRY_DSN to verify; re-copy from Project Settings > Client Keys
getClient() returns undefined	SDK not initialized before test code runs	Use node --import ./instrument.mjs flag or import instrument at top of entry
Missing stack trace on exception	Error captured as string instead of Error object	Always pass new Error('...') to captureException, never a bare string
No user context on event	setUser() called after captureException()	Call setUser() before any capture calls
Events delayed > 60 seconds	Network or proxy blocking *.ingest.sentry.io	Check firewall rules; test with curl https://sentry.io/api/0/
Sentry Logger [warn]: Too many requests	Rate limited by Sentry ingest	Lower tracesSampleRate in init; check quota at Settings > Subscription
flush() times out	Large event queue or slow network	Increase timeout: Sentry.flush(10000); check network latency
Breadcrumbs not appearing	Max breadcrumbs exceeded (default 100)	Configure maxBreadcrumbs in Sentry.init() or clear with Sentry.getCurrentScope().clearBreadcrumbs()

Resources

• Capturing Errors — Node.js
• Capturing Errors — Python
• Enriching Events — Context, Tags, User
• Breadcrumbs Guide
• Sentry Issue Search Syntax

Next Steps

Proceed to sentry-error-capture for production error-handling patterns with scope isolation, custom fingerprinting, and error grouping strategies.