The kafka telemetry exporter enables TrustGate to emit real-time telemetry events to an Apache Kafka topic. This includes both request-level traces and plugin execution metrics, which are serialized into structured JSON messages and delivered using a Kafka producer. This exporter allows seamless integration with downstream consumers, including observability platforms, security analytics pipelines, and operational dashboards.

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Configuration Example

curl -X POST "http://localhost:8080/api/v1/gateways" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Kafka Exporter Gateway",
    "telemetry": {
      "enable_request_traces": true,
      "enable_plugin_traces": true,
      "extra_params": {
        "app_id": "12345"
      },
      "exporters": [
        {
          "name": "kafka",
          "settings": {
            "host": "localhost",
            "port": "9092",
            "topic": "metrics"
          }
        }
      ]
    }
  }'

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Configuration Parameters

To activate the Kafka exporter, include it in the gateway’s telemetry section:
ParameterTypeRequiredDescription
hoststringYesKafka broker host (e.g., "localhost").
portstringYesKafka broker port (e.g., "9092").
topicstringYesKafka topic where telemetry messages will be published.

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Field Descriptions

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enable_request_traces

Enables top-level request tracing. Each incoming request will emit a single summary event containing:
  • Latency (latency_ms)
  • Request and response headers
  • HTTP method and status code
  • Device and client metadata (when available)
This provides end-to-end visibility into the request lifecycle.

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enable_plugin_traces

Enables plugin-level tracing. Each plugin executed during the request lifecycle will produce a separate telemetry event containing:
  • Input and output values for the plugin
  • Error messages or failure states (if any)
  • Execution timing and plugin identifier
This allows for detailed diagnostics and plugin performance monitoring.

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extra_params

A flexible key-value object that appends static metadata to every telemetry event emitted—both request and plugin traces. For example: 
"extra_params": {
  "app_id": "12345"
}
This configuration results in all Kafka events including the field "app_id": "12345" in their payloads. This is useful for:
  • Multi-tenant tracing Distinguish metrics between different applications, clients, or tenants.
  • Environment or region tagging Identify the source environment (e.g., staging, production) or deployment region.
  • Custom labeling for analytics or filtering Enhance downstream processing by attaching meaningful, queryable metadata to every event.

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Kafka Message Format

Each Kafka message represents a telemetry event associated with a request processed by TrustGate. The structure differs slightly based on whether the event is a plugin execution trace or a request trace, but both share a common schema foundation.

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Plugin Metrics Event

This message is emitted for each plugin executed during a request: 
{
    "trace_id": "31a679ea-b752-4546-856a-8cde573500a2",
    "interaction_id": "15ccac5a-dace-4c9d-9e5b-192c1f1530fc",
    "conversation_id": "4d8c6abd-bcfb-4022-8f0c-00d905533f94",
    "input": "{...}",
    "output": "{...}",
    "task": "message",
    "type": "trace",
    "start_timestamp": 1744713336,
    "end_timestamp": 1744713345,
    "latency_ms": 8836,
    "ip": "::1",
    "params": {
        "app_id": "12345"
    },
    "method": "POST",
    "error": "Post \"http://...\": context deadline exceeded",
    "request_headers": {
        "User-Agent": [
            "..."
        ]
    },
    "response_headers": {
        "Content-Type": [
            "application/json"
        ]
    },
    "plugin": {
        "plugin_name": "external_api",
        "stage": "pre-request",
        "extras": {
            "endpoint": "https://api.example.com/validate",
            "method": "POST",
            "status_code": 200,
            "duration_ms": 512,
            "response": "response body"
        }
    },
    "status_code": 502
}

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Request-Level Trace Event

{
  "trace_id": "66b3877b-b124-4e41-a538-4191d5630f3b",
  "interaction_id": "ceca3cf6-faa9-4f7c-8b85-788c4f853f96",
  "conversation_id": "d6b2e0f5-5648-44be-8344-ec18f6b6dfea",
  "input": "",
  "output": "{\"message\":\"pong\"}",
  "task": "message",
  "type": "trace",
  "start_timestamp": 1744382780,
  "end_timestamp": 1744382780,
  "latency_ms": 6,
  "ip": "192.168.1.1",
  "params": {
    "app_id": "12345"
  },
  "method": "GET",
  "device": "Computer",
  "os": "OSWindows 10.0",
  "browser": "BrowserUnknown 0.0",
  "upstream": {
    "target": {
      "path": "/__/ping",
      "host": "localhost",
      "port": 8081
    }
  },
  "request_headers": {
    "User-Agent": ["Mozilla/5.0 ..."],
    ...
  },
  "response_headers": {
    "Content-Type": ["application/json"],
    ...
  },
  "status_code": 200
}
Note: Both event types share the same trace_id, allowing downstream systems to correlate plugin metrics with the parent request.

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How It Works

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Initialization

A Kafka producer is initialized using the specified broker address (host:port) and target topic. This setup prepares the exporter to begin sending telemetry events as soon as they are generated.

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Message Construction

Each telemetry event is serialized into a JSON-formatted message. These messages commonly include fields such as:
  • trace_id
  • latency_ms
  • method
  • status_code
  • headers
  • input / output
  • Device context (e.g., device, os, browser)

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Message Delivery

Messages are published asynchronously to the configured Kafka topic. A delivery channel is used to confirm whether the message was successfully received or if a transmission error occurred.

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Failure Tolerance

The exporter includes error handling for all stages of message transmission:
  • If the Kafka producer is uninitialized or has been closed