Merge pull request #3 from pbinitiative/feature/small-improvements

 - Initialize ApiClient during the Spring application context initialization lifecycle to prevent creation of multiple appClients  - Use safer AtomicBoolean instead of volatile boolean for safer multithreaded use case  - Add command to build the project straight from README.md

Author: alisku

README.md

@@ -10,6 +10,9 @@
 * OpenTelemetry interceptors for REST and spans for gRPC
 * Configurable HTTP/gRPC logging
 
+## Build this project
+``mvn clean package``
+
 ## Getting started
 
 Add the starter to your application and the core client as needed.

zenbpm-spring-boot-starter/src/main/java/org/zenbpm/grpc/ZenbpmJobWorkerManager.java

@@ -28,6 +28,7 @@
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -41,7 +42,7 @@ public class ZenbpmJobWorkerManager implements BeanPostProcessor, SmartLifecycle
 
     private final Map<String, Handler> handlers = new ConcurrentHashMap<>();
 
-    private volatile boolean running = false;
+    private final AtomicBoolean running = new AtomicBoolean(false);
 
     private ManagedChannel channel;
     private StreamObserver<Zenbpm.JobStreamRequest> requestObserver;
@@ -70,7 +71,7 @@ public Object postProcessAfterInitialization(@NotNull Object bean, @NotNull Stri
 
     @Override
     public void start() {
-        if (running || handlers.isEmpty()) {
+        if (running.get() || handlers.isEmpty()) {
             return;
         }
         ManagedChannelBuilder<?> chBuilder = ManagedChannelBuilder
@@ -99,13 +100,13 @@ public void onNext(Zenbpm.JobStreamResponse resp) {
             @Override
             public void onError(Throwable t) {
                 log.error("Stream error", t);
-                running = false;
+                running.set(false);
             }
 
             @Override
             public void onCompleted() {
                 log.info("Stream completed by server");
-                running = false;
+                running.set(false);
             }
         };
 
@@ -120,7 +121,7 @@ public void onCompleted() {
             requestObserver.onNext(req);
         }
 
-        running = true;
+        running.set(true);
     }
 
     private Collection<String> getJobTypes() {
@@ -228,7 +229,7 @@ private ByteString serializeResult(Object result) throws JsonProcessingException
 
     @Override
     public void stop() {
-        if (!running) return;
+        if (!running.get()) return;
         try {
             if (requestObserver != null) {
                 try {
@@ -245,13 +246,13 @@ public void stop() {
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();
         } finally {
-            running = false;
+            running.set(false);
         }
     }
 
     @Override
     public boolean isRunning() {
-        return running;
+        return running.get();
     }
 
     @Override

zenbpm-spring-boot-starter/src/main/java/org/zenbpm/rest/ZenbpmClientService.java

@@ -10,6 +10,8 @@
 import org.zenbpm.ZenbpmClientProperties;
 import org.zenbpm.client.ApiClient;
 
+import javax.annotation.PostConstruct;
+
 @Service
 public class ZenbpmClientService {
 
@@ -20,41 +22,43 @@ public class ZenbpmClientService {
 
     private ApiClient apiClient;
 
-    public ApiClient getApiClient() {
-        initApiClient();
-        return apiClient;
-    }
-
     public ZenbpmClientService(ZenbpmClientProperties properties, ObjectProvider<OpenTelemetry> openTelemetry) {
         this.properties = properties;
         this.openTelemetry = openTelemetry;
     }
 
+    @PostConstruct
+    private void init() {
+        initApiClient();
+    }
+
+    public ApiClient getApiClient() {
+        return apiClient;
+    }
+
     private void initApiClient() {
-        if (apiClient == null) {
-            apiClient = new ApiClient();
-            apiClient.setBasePath(properties.getRestUrl());
-
-            OkHttpClient.Builder builder = apiClient.getHttpClient().newBuilder();
-
-            OpenTelemetry otel = openTelemetry.getIfAvailable();
-            if (properties.isOtelEnabled() && otel != null) {
-                builder.addInterceptor(new ZenbpmOkHttpOtelInterceptor(otel));
-            }
-
-            if (properties.isRestLoggingEnabled()) {
-                HttpLoggingInterceptor.Logger slf4jLogger = this::logHttpMessage;
-                HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor(slf4jLogger);
-                interceptor.setLevel(
-                        log.isTraceEnabled()
-                                ? HttpLoggingInterceptor.Level.BODY
-                                : HttpLoggingInterceptor.Level.BASIC
-                );
-                builder.addInterceptor(interceptor);
-            }
-
-            apiClient.setHttpClient(builder.build());
+        apiClient = new ApiClient();
+        apiClient.setBasePath(properties.getRestUrl());
+
+        OkHttpClient.Builder builder = apiClient.getHttpClient().newBuilder();
+
+        OpenTelemetry otel = openTelemetry.getIfAvailable();
+        if (properties.isOtelEnabled() && otel != null) {
+            builder.addInterceptor(new ZenbpmOkHttpOtelInterceptor(otel));
+        }
+
+        if (properties.isRestLoggingEnabled()) {
+            HttpLoggingInterceptor.Logger slf4jLogger = this::logHttpMessage;
+            HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor(slf4jLogger);
+            interceptor.setLevel(
+                    log.isTraceEnabled()
+                            ? HttpLoggingInterceptor.Level.BODY
+                            : HttpLoggingInterceptor.Level.BASIC
+            );
+            builder.addInterceptor(interceptor);
         }
+
+        apiClient.setHttpClient(builder.build());
     }
 
     private void logHttpMessage(String message) {