CDEvents in Action #1: Simulate a Consumer

Before you build your CDEvents integration, test your approach. Three methods help you understand event flows and validate your strategy before writing production code.

The Testing Problem

You understand why CDEvents matter for pipeline visibility. Now you want to integrate, but you're facing the classic integration challenge:

• How do I know my events will work?
• What should I expect to receive?
• How do I test without building everything first?

Building an event consumer before understanding the data flow is like writing SQL queries before seeing the database schema. You need to simulate receiving events first.

Three Approaches to Simulate CDEvents Consumption

Each approach serves different needs and skill levels:

Approach	Best For	Setup Time	Real Data
webhook.site	Quick testing, event structure exploration	30 seconds	❌ Manual only
CDviz docker compose	Full pipeline simulation, realistic testing	3 minutes	✅ Demo events
cdviz-collector connect ⭐	Local development, production debugging	2 minutes	✅ Real events

Let's explore each approach and learn when to use them.

Approach 1: webhook.site - Quick Event Structure Testing

When to use: Exploring CDEvents structure, quick prototyping, learning event schemas

Perfect for: Developers new to CDEvents who want to see event structure immediately

Step 1: Get Your Unique Webhook URL

1. Visit webhook.site
2. Copy your unique URL (looks like https://webhook.site/12345678-abcd-...)
3. Leave the tab open to see incoming requests

Step 2: Send a Test CDEvent

# Send a deployment event to your webhook.site URL
curl -X POST https://webhook.site/YOUR-UNIQUE-ID \
  -H "Content-Type: application/json" \
  -d '{
    "context": {
      "version": "0.4.1",
      "id": "test-123",
      "source": "my-pipeline",
      "type": "dev.cdevents.service.deployed.0.2.0",
      "timestamp": "'$(date -u +%Y-%m-%dT%H:%M:%SZ)'"
    },
    "subject": {
      "id": "my-service",
      "type": "service",
      "content": {
        "environment": {"id": "production"},
        "artifactId": "pkg:oci/my-service@v1.2.3"
      }
    }
  }'

Step 3: Analyze the Event Structure

Switch back to webhook.site to see your event. Notice:

• Headers: Content-Type, user agent, IP address
• Body: Complete CDEvent structure
• Timing: When the event was received
• Size: Event payload size

What You Learn

✅ Event structure: See exactly what CDEvents look like ✅ Header requirements: Understand HTTP headers needed ✅ JSON schema: Valid CDEvent format and required fields ✅ Quick iteration: Test different event types rapidly

❌ No processing: Events just display, no storage or correlation ❌ Manual only: You must send events yourself ❌ No authentication: Simple HTTP POST only

Best practice: Use webhook.site to understand CDEvents structure before building your consumer logic.

Approach 2: CDviz docker compose - Realistic Pipeline Testing

When to use: Testing complete event flows, understanding CDviz integration, realistic event scenarios

Perfect for: Teams evaluating CDviz, developers building CDEvents integration, demonstrating event flows with visual dashboards

Step 1: Start CDviz Demo Environment

# Clone and start the full CDviz stack
git clone https://github.com/cdviz-dev/cdviz.git
cd cdviz/demos/stack-compose
docker compose up

What starts up:

• CDviz collector (event ingestion)
• PostgreSQL + TimescaleDB (event storage)
• Grafana (visualization dashboards)
• Demo event generator (realistic test data)

Step 2: Observe Automatic Demo Events

Open localhost:3000 for Grafana dashboards. You'll immediately see:

• Service deployments across different environments
• Pipeline executions with success/failure patterns
• Artifact promotions through staging to production
• Timeline visualization showing event correlations

Step 3: Send Your Own Events

The CDviz collector accepts events at http://localhost:8080/webhook/000-cdevents:

# Send a custom deployment event
curl -X POST http://localhost:8080/webhook/000-cdevents \
  -H "Content-Type: application/json" \
  -d '{
    "context": {
      "version": "0.4.1",
      "id": "my-test-deployment",
      "source": "my-testing",
      "type": "dev.cdevents.service.deployed.0.2.0",
      "timestamp": "'$(date -u +%Y-%m-%dT%H:%M:%SZ)'"
    },
    "subject": {
      "id": "my-namespace/my-test-service/my-container",
      "type": "service",
      "content": {
        "environment": {"id": "testing"},
        "artifactId": "pkg:oci/my-test-service@v2.1.0"
      }
    }
  }'

Result: Your event appears in Grafana dashboards alongside demo events, showing realistic integration.

Step 4: Explore Event Correlation

Browse different Grafana dashboards to understand:

• Service Timeline: How your events fit into deployment flows
• Environment View: Cross-environment event correlation
• Activity Feed: Chronological event stream
• Direct Database: Query PostgreSQL directly for custom analysis

What You Learn

✅ Complete integration: Full event processing pipeline ✅ Visual feedback: See events in realistic dashboards ✅ Event correlation: Understand how events relate to each other ✅ Storage patterns: Events stored in PostgreSQL for analysis ✅ Production simulation: Realistic event processing behavior

❌ Resource intensive: Requires Docker and multiple containers ❌ Complex setup: More moving parts than simple webhook testing

Best practice: Use CDviz docker compose when evaluating CDEvents for your team or testing integration patterns.

Approach 3: cdviz-collector connect - Recommended for Development ⭐

When to use: Local development, troubleshooting integrations, validating event flows

Perfect for: Developers building CDEvents integration, DevOps engineers debugging event flows

Step 1: Install cdviz-collector CLI

All installation options are documented at CDviz Collector Installation Guide

brew install cdviz-dev/tap/cdviz-collector

If native pre-built binary is not available for your platform (e.g. Windows) you can fallback to the docker image.

Step 2: Launch with a local debug configuration

Create a configuration with a webhook as source (input) and a debug sink (output)

# cdviz-collector-debug.toml

[http]
host = "0.0.0.0"
port = 8080

[sinks.debug]
enabled = true
type = "debug"
format = "json"
destination = "stdout"

[sources.cdevents_webhook]
enabled = true

[sources.cdevents_webhook.extractor]
type = "webhook"
id = "000-cdevents"

Launch

cdviz-collector connect -v --config ./cdviz-collector-debug.toml

What this does:

• Starts a local CDviz collector instance
• Shows real-time events as they arrive on stdout
• Validates CDEvent format and rejects invalid events
• Provides a lightweight development environment without Docker

Step 3: Send Your Own Events

# Send a custom deployment event
curl -X POST http://localhost:8080/webhook/000-cdevents \
  -H "Content-Type: application/json" \
  -d '{
    "context": {
      "version": "0.4.1",
      "id": "my-test-deployment",
      "source": "my-testing",
      "type": "dev.cdevents.service.deployed.0.2.0",
      "timestamp": "'$(date -u +%Y-%m-%dT%H:%M:%SZ)'"
    },
    "subject": {
      "id": "my-namespace/my-test-service/my-container",
      "type": "service",
      "content": {
        "environment": {"id": "testing"},
        "artifactId": "pkg:oci/my-test-service@v2.1.0"
      }
    }
  }'

What You Learn

✅ CDEvent validation: Immediate feedback on event format and structure ✅ Lightweight development: No Docker required, fast startup ✅ Real-time debugging: See events as they arrive with validation feedback ✅ Configuration flexibility: Easy to modify behavior via TOML config

❌ Command-line only: No visual interface like Grafana ❌ Local only: Events not persisted or aggregated

Best practice: Use cdviz-collector connect as your primary development tool for CDEvents integration.

Choosing Your Testing Approach

Decision Framework

Start with webhook.site if:

• You're new to CDEvents and want to understand event structure
• You need quick experimentation with different event formats
• You're prototyping and don't need full pipeline simulation

Use CDviz docker compose if:

• You're evaluating CDviz for your organization
• You want to see realistic event flows and correlations
• You need to test integration patterns before production deployment
• You want to explore Grafana dashboards and event visualization

Use cdviz-collector connect if (⭐ Recommended):

• You're developing CDEvents integration locally
• You want fast feedback on event validation
• You prefer lightweight tools without Docker overhead
• You need flexible configuration for different scenarios

Progression Strategy

Recommended learning path:

1. webhook.site (5 minutes) → Understand CDEvent structure
2. cdviz-collector connect (10 minutes) → Validate and debug locally ⭐
3. CDviz docker compose (15 minutes) → See complete integration with dashboards

For most developers, cdviz-collector connect provides the best balance of simplicity and functionality for ongoing development work.

This progression gives you theoretical knowledge, practical experience, and production debugging skills.

Next Steps: From Consumer to Producer

Now that you understand how to receive and inspect CDEvents, you're ready to learn how to send them from your own tools and pipelines.

Try these experiments:

1. Pick one simulation approach above and test it
2. Send different CDEvent types (service.deployed, taskrun.finished, artifact.published)
3. Note what you learned about event structure and timing

This foundation will help you build robust CDEvents integration in your own systems.

Key Takeaways

🎯 Test first: Simulate receiving events before building producers 🔧 Multiple tools: Different approaches serve different testing needs ⭐ Recommended approach: cdviz-collector connect for most development work 📊 Visual integration: CDviz docker compose for complete pipeline visualization 📈 Progressive learning: Start simple (webhook.site) then build practical skills

Understanding how to consume CDEvents is essential before producing them. These simulation approaches give you the foundation to build robust CDEvents integration.

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Resources:

• webhook.site - Instant webhook testing
• CDviz Demo Setup - Full docker compose stack
• CDEvents Specification - Complete event standard reference
• CDviz Documentation - Complete installation and configuration guides