codebase/spring-ai-a2a [BAEL-9705]

spring-ai-modules/pom.xml

@@ -20,6 +20,7 @@
         <module>spring-ai-2</module>
         <module>spring-ai-3</module>
         <module>spring-ai-4</module>
+        <module>spring-ai-a2a</module>
         <module>spring-ai-agent-skills</module>
         <module>spring-ai-agentic-patterns</module>
         <module>spring-ai-anthropic-agent-skills</module>

spring-ai-modules/spring-ai-a2a/pom.xml

@@ -0,0 +1,91 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>spring-ai-modules</artifactId>
+        <version>0.0.1</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>spring-ai-a2a</artifactId>
+    <version>0.0.1</version>
+    <name>spring-ai-a2a</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webmvc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.ai</groupId>
+            <artifactId>spring-ai-starter-model-openai</artifactId>
+            <version>${spring-ai.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springaicommunity</groupId>
+            <artifactId>spring-ai-a2a-server-autoconfigure</artifactId>
+            <version>${spring-ai-a2a-server-config.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.github.a2asdk</groupId>
+            <artifactId>a2a-java-sdk-client</artifactId>
+            <version>${a2a-client.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webmvc-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <java.version>21</java.version>
+        <junit-jupiter.version>6.0.3</junit-jupiter.version>
+        <spring-boot.version>4.0.6</spring-boot.version>
+        <spring-ai.version>2.0.0</spring-ai.version>
+        <spring-ai-a2a-server-config.version>0.3.0</spring-ai-a2a-server-config.version>
+        <a2a-client.version>0.3.3.Final</a2a-client.version>
+    </properties>
+
+    <profiles>
+        <profile>
+            <id>skills-matcher-server</id>
+            <activation>
+                <activeByDefault>true</activeByDefault>
+            </activation>
+            <properties>
+                <spring.boot.mainclass>com.baeldung.a2a.server.skillsmatcher.SkillsMatcherServer</spring.boot.mainclass>
+            </properties>
+        </profile>
+        <profile>
+            <id>salary-evaluator-server</id>
+            <properties>
+                <spring.boot.mainclass>com.baeldung.a2a.server.salaryevaluator.SalaryEvaluatorServer</spring.boot.mainclass>
+            </properties>
+        </profile>
+        <profile>
+            <id>job-screening-orchestrator-client</id>
+            <properties>
+                <spring.boot.mainclass>com.baeldung.a2a.client.orchestrator.jobscreening.JobScreeningOrchestrator</spring.boot.mainclass>
+            </properties>
+        </profile>
+    </profiles>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <configuration>
+                    <mainClass>${spring.boot.mainclass}</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/AgentRegistry.java

@@ -0,0 +1,39 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import io.a2a.A2A;
+import io.a2a.spec.AgentCard;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+@Component
+class AgentRegistry {
+
+    private final Map<String, AgentCard> agentCards = new HashMap<>();
+
+    AgentRegistry(@Value("${remote.agents.urls}") List<String> agentUrls) throws URISyntaxException {
+        for (String url : agentUrls) {
+            String path = new URI(url).getPath();
+            AgentCard card = A2A.getAgentCard(url, path + ".well-known/agent-card.json", null);
+            agentCards.put(card.name(), card);
+        }
+    }
+
+    AgentCard get(String agentName) {
+        return agentCards.get(agentName);
+    }
+
+    String describeAgents() {
+        return agentCards
+            .values()
+            .stream()
+            .map(card -> "- " + card.name() + ": " + card.description())
+            .collect(Collectors.joining("\n"));
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/ChatClientConfiguration.java

@@ -0,0 +1,29 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+class ChatClientConfiguration {
+
+    @Bean
+    ChatClient chatClient(
+        ChatClient.Builder chatClientBuilder,
+        AgentRegistry agentRegistry,
+        RemoteAgentTools remoteAgentTools
+    ) {
+        return chatClientBuilder
+            .defaultSystem("""
+                You are a job-screening orchestrator for recruiters.
+                You do not evaluate candidates yourself. Instead, you delegate
+                to the following remote agents:
+
+                %s
+
+                Once all agents have responded, combine their responses into a short screening summary.
+                """.formatted(agentRegistry.describeAgents()))
+            .defaultTools(remoteAgentTools)
+            .build();
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/JobScreeningController.java

@@ -0,0 +1,39 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+class JobScreeningController {
+
+    private final ChatClient chatClient;
+
+    JobScreeningController(ChatClient chatClient) {
+        this.chatClient = chatClient;
+    }
+
+    @PostMapping("/screenings")
+    ScreeningResponse screenCandidate(@RequestBody ScreeningRequest screeningRequest) {
+        String verdict = chatClient
+            .prompt()
+            .user(screeningRequest.toString())
+            .call()
+            .content();
+        return new ScreeningResponse(verdict);
+    }
+
+    record ScreeningRequest(
+        String name,
+        String email,
+        String jobTitle,
+        String requiredSkills,
+        String candidateSkills,
+        int expectedSalary
+    ) {}
+
+    record ScreeningResponse(
+        String verdict
+    ) {}
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/JobScreeningOrchestrator.java

@@ -0,0 +1,15 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import org.springaicommunity.a2a.server.autoconfigure.A2AServerAutoConfiguration;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication(exclude = A2AServerAutoConfiguration.class)
+@PropertySource("classpath:application-job-screening-orchestrator.properties")
+class JobScreeningOrchestrator {
+
+    public static void main(String[] args) {
+        SpringApplication.run(JobScreeningOrchestrator.class, args);
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/RemoteAgentClient.java

@@ -0,0 +1,71 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import io.a2a.A2A;
+import io.a2a.client.Client;
+import io.a2a.client.ClientEvent;
+import io.a2a.client.TaskEvent;
+import io.a2a.client.config.ClientConfig;
+import io.a2a.client.transport.jsonrpc.JSONRPCTransport;
+import io.a2a.client.transport.jsonrpc.JSONRPCTransportConfig;
+import io.a2a.spec.AgentCard;
+import io.a2a.spec.Artifact;
+import io.a2a.spec.Message;
+import io.a2a.spec.Part;
+import io.a2a.spec.TextPart;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.function.BiConsumer;
+import java.util.stream.Collectors;
+
+@Component
+class RemoteAgentClient {
+
+    private final AgentRegistry agentRegistry;
+
+    RemoteAgentClient(AgentRegistry agentRegistry) {
+        this.agentRegistry = agentRegistry;
+    }
+
+    String sendMessage(String agentName, String task)
+        throws ExecutionException, InterruptedException, TimeoutException {
+        AgentCard agentCard = agentRegistry.get(agentName);
+
+        CompletableFuture<String> response = new CompletableFuture<>();
+        BiConsumer<ClientEvent, AgentCard> responseConsumer = (event, card) -> {
+            TaskEvent taskEvent = (TaskEvent) event;
+            response.complete(taskEvent.getTask()
+                .getArtifacts()
+                .stream()
+                .map(Artifact::parts)
+                .map(this::extractText)
+                .collect(Collectors.joining("\n")));
+        };
+
+        Client client = Client.builder(agentCard)
+            .clientConfig(new ClientConfig.Builder()
+                .setAcceptedOutputModes(List.of("text"))
+                .build())
+            .withTransport(JSONRPCTransport.class, new JSONRPCTransportConfig())
+            .addConsumers(List.of(responseConsumer))
+            .streamingErrorHandler(response::completeExceptionally)
+            .build();
+
+        Message message = A2A.toUserMessage(task);
+        client.sendMessage(message);
+        return response.get(60, TimeUnit.SECONDS);
+    }
+
+    private String extractText(List<Part<?>> parts) {
+        return parts
+            .stream()
+            .filter(TextPart.class::isInstance)
+            .map(TextPart.class::cast)
+            .map(TextPart::getText)
+            .collect(Collectors.joining("\n"));
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/client/orchestrator/jobscreening/RemoteAgentTools.java

@@ -0,0 +1,29 @@
+package com.baeldung.a2a.client.orchestrator.jobscreening;
+
+import org.springframework.ai.tool.annotation.Tool;
+import org.springframework.ai.tool.annotation.ToolParam;
+import org.springframework.stereotype.Service;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeoutException;
+
+@Service
+class RemoteAgentTools {
+
+    private final RemoteAgentClient remoteAgentClient;
+
+    RemoteAgentTools(RemoteAgentClient remoteAgentClient) {
+        this.remoteAgentClient = remoteAgentClient;
+    }
+
+    @Tool(
+        name = "send-message-to-agent",
+        description = "Sends a task to a remote agent and returns its response."
+    )
+    String sendMessageToAgent(
+        @ToolParam(description = "Name of the remote agent") String agentName,
+        @ToolParam(description = "The task to perform") String task
+    ) throws ExecutionException, InterruptedException, TimeoutException {
+        return remoteAgentClient.sendMessage(agentName, task);
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/server/backgroundchecker/BackgroundCheckerServer.java

@@ -0,0 +1,14 @@
+package com.baeldung.a2a.server.backgroundchecker;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication
+@PropertySource("classpath:application-background-checker-server.properties")
+public class BackgroundCheckerServer {
+
+    public static void main(String[] args) {
+        SpringApplication.run(BackgroundCheckerServer.class, args);
+    }
+}

spring-ai-modules/spring-ai-a2a/src/main/java/com/baeldung/a2a/server/backgroundchecker/BackgroundCheckerTools.java

@@ -0,0 +1,47 @@
+package com.baeldung.a2a.server.backgroundchecker;
+
+import org.springframework.ai.tool.annotation.Tool;
+import org.springframework.ai.tool.annotation.ToolParam;
+import org.springframework.stereotype.Service;
+
+import java.util.Set;
+
+@Service
+class BackgroundCheckerTools {
+
+    private static final Set<String> TRUSTED_EMAIL_DOMAINS = Set.of(
+        "gmail.com",
+        "baeldung.com"
+    );
+
+    @Tool(
+        name = "check-background",
+        description = "Runs a background check for a candidate"
+    )
+    BackgroundCheckResult checkBackground(
+        @ToolParam(description = "The candidate's full name") String candidateName,
+        @ToolParam(description = "The candidate's email address") String email
+    ) {
+        String domain = extractDomain(email);
+        Verdict verdict = TRUSTED_EMAIL_DOMAINS.contains(domain)
+            ? Verdict.CLEAR
+            : Verdict.NEEDS_REVIEW;
+        return new BackgroundCheckResult(verdict);
+    }
+
+    private String extractDomain(String email) {
+        int atIndex = email.lastIndexOf('@');
+        return atIndex < 0
+            ? ""
+            : email.substring(atIndex + 1).trim().toLowerCase();
+    }
+
+    record BackgroundCheckResult(
+        Verdict verdict
+    ) {}
+
+    enum Verdict {
+        CLEAR,
+        NEEDS_REVIEW
+    }
+}