micronaut

Files (7)

• SKILL.md
• micronaut-configuration.md · references/
• micronaut-data.md · references/
• micronaut-deployment.md · references/
• micronaut-security.md · references/
• micronaut-setup.md · references/
• micronaut-testing.md · references/

SKILL.md (first lines)

# Micronaut

## Purpose
Build Micronaut applications with compile-time dependency injection, reactive HTTP servers, AOT compilation, GraalVM native image support, and declarative HTTP clients.

## Agent Protocol

### Trigger
User request includes: `Micronaut`, `micronaut framework`, `micronaut DI`, `micronaut reactive`, `micronaut controller`, `micronaut client`, `micronaut native image`, `micronaut graalvm`.

### Input Context
- JDK version (17+, 21+)
- Micronaut version (4.x)
- Build tool (Gradle, Maven)
- Database (JDBC, R2DBC, MongoDB)
- Features (Reactive, Declarative Client, AOT, Security)

### Output Artifact
Project setup, controller pattern, DI configuration, client setup, native image config.

### Response Format
Produce artifact directly. No preamble, no postamble, no explanations. No filler, no hedging.

### Completion Criteria
- Application class with @Singleton beans
- Controller with @Get/@Post/@Body/@QueryValue
- Declarative @Client for HTTP calls
- Configuration via @ConfigurationProperties
- Native image configuration for GraalVM
- Reactive endpoints with Mono/Flux

### Max Response Length
4096 tokens

## Architecture Decision Trees

### Micronaut vs Spring Boot vs Quarkus

| Criterion | Micronaut | Spring Boot | Quarkus |
|-----------|-----------|-------------|---------|
| Startup time | < 100ms (AOT) | 2-5s (reflection) | < 200ms (AOT) |
| Memory footprint | ~50MB | ~200MB | ~100MB |
| Native image | GraalVM first-class | Spring Native 3+ | GraalVM first-class |
| DI approach | Compile-time (annotation processing) | Runtime (reflection) | Runtime + Quarkus Arc |
| Reactive support | Netty (built-in) | WebFlux | Vert.x |
| Gradle/Maven | Excellent | Excellent | Excellent |

Decision: Fast startup + low memory → Micronaut. Full Spring ecosystem → Spring Boot. Fast + Funqy/extension-first → Quarkus.

### Reactive vs Imperative Controllers

| Aspect | Reactive (Mono/Flux) | Imperative (POJO) |
|--------|---------------------|-------------------|
| Thread model | Event loop | Request-per-thread |
| Database | R2DBC (reactive) | JDBC (blocking) |
| Error handling | Operators (onErrorReturn) | try/catch |
| Testing | StepVerifier | JUnit assertions |
| Stack depth | Sometimes harder to debug | Predictable |

Decision: High concurrency with few DB connections → Reactive. Traditional CRUD with JDBC → Imperative.

## Workflow

### Step 1: Project Setup (Gradle)

```groovy
// build.gradle
plugins {
    id 'io.micronaut.application' version '4.3.0'
    id 'io.micronaut.aot' version '4.3.0'
}

micronaut {
    version = '4.3.0'
    runtime = 'netty'
    testRuntime = 'junit5'
    processing {
        incremental(true)
        annotations('com.example.*')
    }
    aot {
        optimizeServiceLoading = true
        convertYamlToJava = true
        precomputeOperations = true
        optimizeNetty = true
    }
}

dependencies {
    annotationProcessor 'io.micronaut:micronaut-http-validation'
    annotationProcessor 'io.micronaut.serde:micronaut-serde-processor'
    implementation 'io.micronaut:micronaut-http-server-netty'
    implementation 'io.micronaut.serde:micronaut-serde-jackson'
    implementation 'io.micronaut.data:micronaut-data-jdbc'
    implementation 'io.micronaut.sql:micronaut-jdbc-hikari'
    implementation 'io.micronaut:micronaut-validation'
    runtimeOnly 'org.postgresql:postgresql'
    testImplementation 'io.micronaut.test:micronaut-test-junit5'
}
```

### Step 2: Application and Configuration

```java
// src/main/java/com/example/Application.java
@Micronaut
public class Application {
    public static void main(String[] args) {
        Micronaut.run(Application.class, args);
    }
}

// src/main/resources/application.yml
micronaut:
  server:
    port: 8080
    netty:
      max-header-size: 8192
      worker:

From j4flmao/agent-skills, MIT.

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