Axon-Sentry-Tracing

Distributed tracing for Axon Framework with Sentry via OpenTelemetry

axon-sentry-tracing seamlessly integrates Sentry's performance monitoring and error tracking with Axon Framework applications through OpenTelemetry instrumentation. Get end-to-end visibility into your event-sourced, CQRS applications with minimal configuration.

Features

• Automatic Tracing - Commands, events, queries, sagas, and event processors automatically traced
• OpenTelemetry Native - Built on industry-standard OpenTelemetry for maximum compatibility
• Sentry Integration - View traces and errors in Sentry's powerful UI
• Spring Boot Auto-Configuration - Zero-config setup for Spring Boot applications
• Distributed Tracing - Trace propagation across async boundaries and distributed systems
• Configurable - Fine-grained control over what gets traced and captured
• Production Ready - Optimized for performance with configurable sampling
• Type Safe - Written in Kotlin with full type safety

Quick Start

Maven

<dependency>
    <groupId>io.github.yourusername</groupId>
    <artifactId>axon-sentry-tracing</artifactId>
    <version>0.1.0</version>
</dependency>

Gradle (Kotlin DSL)

implementation("io.github.yourusername:axon-sentry-tracing:0.1.0")

Configuration (Spring Boot)

Add to application.yml:

axon:
  sentry:
    tracing:
      enabled: true
      sentry-dsn: ${SENTRY_DSN}
      environment: production
      traces-sample-rate: 0.1  # Sample 10% of traces

That's it! All Axon messages will now be traced and sent to Sentry.

Usage Example

Domain Code (No Changes Required!)

@Aggregate
class BankAccount {
    @AggregateIdentifier
    private lateinit var accountId: UUID

    @CommandHandler
    constructor(command: CreateAccountCommand) {
        // Command automatically traced
        AggregateLifecycle.apply(AccountCreatedEvent(command.accountId))
    }
}

@Component
class AccountProjection {
    @EventHandler
    fun on(event: AccountCreatedEvent) {
        // Event handling automatically traced
        // Link back to originating command
    }
}

@Component
class AccountQueryHandler {
    @QueryHandler
    fun handle(query: FindAccountQuery): Account {
        // Query automatically traced
        return findAccount(query.accountId)
    }
}

View in Sentry

Navigate to Sentry's Performance dashboard to see:

• Command execution spans (e.g., Command: CreateAccountCommand)
• Event publication and processing (e.g., Handle: AccountCreatedEvent)
• Query execution (e.g., Query: FindAccountQuery)
• Full distributed traces across your application
• Performance metrics and error correlation

Architecture

┌─────────────────┐
│  Axon Framework │
│                 │
│  ┌───────────┐  │     ┌──────────────┐
│  │ Commands  │◄─┼─────┤ Interceptors │
│  └───────────┘  │     └──────┬───────┘
│  ┌───────────┐  │            │
│  │  Events   │◄─┼────────────┤
│  └───────────┘  │            │
│  ┌───────────┐  │            │
│  │ Queries   │◄─┼────────────┤
│  └───────────┘  │            │
└─────────────────┘            │
                               │
                    ┌──────────▼──────────┐
                    │  OpenTelemetry SDK  │
                    │                     │
                    │  • Span Creation    │
                    │  • Context Prop.    │
                    │  • Batching         │
                    └──────────┬──────────┘
                               │
                    ┌──────────▼──────────┐
                    │   Sentry Exporter   │
                    │                     │
                    │  • Span Mapping     │
                    │  • Transaction      │
                    │  • Error Tracking   │
                    └──────────┬──────────┘
                               │
                    ┌──────────▼──────────┐
                    │      Sentry.io      │
                    │                     │
                    │  Performance & Errors│
                    └─────────────────────┘

Configuration Options

All configuration via axon.sentry.tracing prefix:

Property	Default	Description
enabled	true	Master switch for tracing
trace-commands	true	Trace command execution
trace-events	true	Trace event processing
trace-queries	true	Trace query execution
trace-event-processors	true	Trace event processors
trace-sagas	true	Trace saga execution
capture-command-payloads	false	Include command payloads (caution: sensitive data)
capture-event-payloads	false	Include event payloads
capture-query-payloads	false	Include query payloads
sentry-dsn	-	Sentry Data Source Name
environment	development	Environment name
traces-sample-rate	1.0	Sample rate (0.0 to 1.0)
tags	{}	Additional tags for all spans

Advanced Usage

Custom Attributes

Add custom attributes to spans:

@Configuration
class TracingConfig {
    @Bean
    fun customAttributeProvider(): CustomAttributeProvider {
        return CustomAttributeProvider { message ->
            mapOf(
                "tenant.id" to extractTenantId(message),
                "user.id" to extractUserId(message)
            )
        }
    }
}

Programmatic Configuration

val config = TracingConfiguration.builder()
    .enabled(true)
    .sentryDsn("https://key@sentry.io/project")
    .tracesSampleRate(0.25)
    .addAttributeProvider { message ->
        mapOf("custom.attribute" to "value")
    }
    .build()

Examples

See the examples directory for complete working applications:

• Spring Boot Demo - Full-featured bank account application
• Coming soon: Microservices example, Saga example

Documentation

• Implementation Issues - Detailed technical documentation
• API Documentation - Generated KDoc
• User Guide - Comprehensive usage guide
• Architecture Decisions - ADRs and design docs

Requirements

• Java 17+
• Kotlin 1.9+
• Axon Framework 4.9+
• Spring Boot 3.2+ (for auto-configuration)

Compatibility

axon-sentry-tracing	Axon Framework	Sentry	OpenTelemetry	Spring Boot
0.1.x	4.9.x	7.x	1.33+	3.2+

Performance

Overhead is minimal and configurable:

• Span Creation: ~10-50μs per span
• Metadata Enrichment: ~5-20μs
• Memory: ~100 bytes per span
• Network: Async batched export (configurable)

Use sampling (traces-sample-rate) to reduce overhead in high-throughput scenarios.

Contributing

Contributions welcome! Please see CONTRIBUTING.md for:

• Code of conduct
• Development setup
• Testing requirements
• Pull request process

Development

Build

./gradlew build

Test

./gradlew test

Code Quality

./gradlew detekt ktlint

Local Publishing

./gradlew publishToMavenLocal

Roadmap

• Core tracing implementation
• Spring Boot auto-configuration
• Saga tracing
• Deadletter queue integration
• Metrics and monitoring
• Performance optimizations
• Kotlin Multiplatform support

See issues for detailed roadmap.

FAQ

Q: Does this work with Axon Server? A: Yes! Tracing works with both embedded event stores and Axon Server.

Q: What's the performance impact? A: Minimal. Use sampling in production to reduce overhead. Typical overhead is <5%.

Q: Can I use this without Spring Boot? A: Yes! Manual configuration is available. See programmatic configuration.

Q: Does this support distributed tracing? A: Yes! Trace context propagates through Axon message metadata across process boundaries.

Q: Can I filter which messages are traced? A: Yes! Use configuration properties to enable/disable command, event, or query tracing.

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions
• Stack Overflow: Tag with axon-framework and sentry

License

Apache License 2.0 - see LICENSE for details.

Acknowledgments

• Axon Framework - Excellent event sourcing and CQRS framework
• Sentry - Powerful error tracking and performance monitoring
• OpenTelemetry - Industry-standard observability framework

Related Projects

• Axon Framework
• Sentry Java SDK
• OpenTelemetry Java

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Status: In Development Version: 0.1.0-SNAPSHOT Maintainer: @yourusername