Expose gRPC port as local.grpc.port. (#59)

If a value of 0 is provided as the port to the ServerBuilder, the server picks a random port on startup. This change makes that port available under the property local.grpc.port so it can be used in unit tests.

Author: dadadom

README.adoc

@@ -27,15 +27,16 @@ dependencies {
 
 * Start by https://github.com/google/protobuf-gradle-plugin[generating] stub and server interface(s) from your `.proto` file(s).
 * Annotate your server interface implementation(s) with `@org.lognet.springboot.grpc.GRpcService`
-* Optionally configure the server port in your `application.yml/properties`. Default port is `6565`
+* Optionally configure the server port in your `application.yml/properties`. Default port is `6565`.
+* A random port can be defined by setting the port to `0`. The actual port being used can then be retrieved from the property `local.grpc.port`.
 
 [source,yaml]
 ----
  grpc:
     port: 6565
 ----
 
-The starter supports also the  `in-process server`, which should be used for testing purposes :
+The starter supports also the `in-process server`, which should be used for testing purposes :
 
 [source,yaml]
 ----

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/GRpcServerRunner.java

@@ -79,7 +79,6 @@ public void run(String... args) throws Exception {
 
                 });
 
-
         configurer.configure(serverBuilder);
         server = serverBuilder.build().start();
 
@@ -88,6 +87,18 @@ public void run(String... args) throws Exception {
 
     }
 
+    /**
+     * Return the port the server is actually running on.
+     *
+     * @return the port the server is actually running on or 0, if the server is not initialized yet
+     */
+    public int getRunningPort() {
+        if (server == null) {
+            return 0;
+        }
+        return server.getPort();
+    }
+
     private ServerServiceDefinition bindInterceptors(ServerServiceDefinition serviceDefinition, GRpcService gRpcService, Collection<ServerInterceptor> globalInterceptors) {
 
 

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/autoconfigure/GRpcAutoConfiguration.java

@@ -3,7 +3,6 @@
 import io.grpc.ServerBuilder;
 import io.grpc.inprocess.InProcessServerBuilder;
 import io.grpc.services.HealthStatusManager;
-import lombok.Getter;
 import org.lognet.springboot.grpc.GRpcServerBuilderConfigurer;
 import org.lognet.springboot.grpc.GRpcServerRunner;
 import org.lognet.springboot.grpc.GRpcService;
@@ -13,12 +12,17 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.ApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.stereotype.Component;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertySource;
+import org.springframework.util.SocketUtils;
+
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * Created by alexf on 25-Jan-16.
@@ -29,17 +33,34 @@
 @EnableConfigurationProperties(GRpcServerProperties.class)
 public class GRpcAutoConfiguration {
 
-
+    @Autowired
+    private ApplicationContext applicationContext;
 
     @Autowired
     private GRpcServerProperties grpcServerProperties;
 
 
 
     @Bean
-    @ConditionalOnProperty(value = "grpc.enabled",havingValue = "true",matchIfMissing = true)
-    public GRpcServerRunner grpcServerRunner(GRpcServerBuilderConfigurer configurer){
-        return new GRpcServerRunner(configurer, ServerBuilder.forPort(grpcServerProperties.getPort()));
+    @ConditionalOnProperty(value = "grpc.enabled", havingValue = "true", matchIfMissing = true)
+    public GRpcServerRunner grpcServerRunner(GRpcServerBuilderConfigurer configurer) {
+        int port = grpcServerProperties.getPort();
+
+        GRpcServerRunner gRpcServerRunner = new GRpcServerRunner(configurer, ServerBuilder.forPort(port));
+
+        if (applicationContext instanceof ConfigurableApplicationContext) {
+            int runningPort = gRpcServerRunner.getRunningPort();
+
+            MutablePropertySources sources = ((ConfigurableApplicationContext) applicationContext).getEnvironment().getPropertySources();
+            PropertySource<?> source = sources.get("server.ports");
+            if (source == null) {
+                source = new MapPropertySource("server.ports", new HashMap<String, Object>());
+                sources.addFirst(source);
+            }
+            ((Map<String, Object>) source.getSource()).put("local.grpc.port", runningPort);
+        }
+
+        return gRpcServerRunner;
     }
 
     @Bean

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/autoconfigure/GRpcServerProperties.java

@@ -5,6 +5,7 @@
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.stereotype.Component;
+import org.springframework.util.SocketUtils;
 
 /**
  * Created by alexf on 26-Jan-16.
@@ -19,6 +20,12 @@ public class GRpcServerProperties {
      */
     private int port = 6565;
 
+    public int getPort() {
+        if (port == 0) {
+            port = SocketUtils.findAvailableTcpPort(40000, 50000);
+        }
+        return port;
+    }
 
     /**
      * Enables the embedded grpc server.