Log when HTTP server can't be started (also shows alert in UI) (#758)

* Log when HTTP server can't be started (also shows alert in UI)

Change default port from 8080 to 2084

* Ask user to continue without HTTP functionality

Author: SamCarlberg

core/src/main/java/edu/wpi/grip/core/Main.java

@@ -2,6 +2,7 @@
 
 import edu.wpi.grip.core.events.ExceptionClearedEvent;
 import edu.wpi.grip.core.events.ExceptionEvent;
+import edu.wpi.grip.core.exception.GripServerException;
 import edu.wpi.grip.core.http.GripServer;
 import edu.wpi.grip.core.http.HttpPipelineSwitcher;
 import edu.wpi.grip.core.operations.CVOperations;
@@ -10,6 +11,7 @@
 import edu.wpi.grip.core.serialization.Project;
 import edu.wpi.grip.core.settings.SettingsProvider;
 import edu.wpi.grip.core.sources.GripSourcesHardwareModule;
+import edu.wpi.grip.core.util.SafeShutdown;
 
 import com.google.common.eventbus.EventBus;
 import com.google.common.eventbus.Subscribe;
@@ -75,7 +77,12 @@ public void start(String[] args) throws IOException, InterruptedException {
     // argument is already taken. Since we have to have the server running to handle remotely
     // loading pipelines and uploading images, as well as potential HTTP publishing operations,
     // this will cause the program to exit.
-    gripServer.start();
+    try {
+      gripServer.start();
+    } catch (GripServerException e) {
+      logger.log(Level.SEVERE, "The HTTP server could not be started", e);
+      SafeShutdown.exit(1);
+    }
 
     if (pipelineRunner.state() == Service.State.NEW) {
       // Loading a project will start the pipeline, so only start it if a project wasn't specified

core/src/main/java/edu/wpi/grip/core/http/GripServer.java

@@ -109,7 +109,7 @@ public enum State {
   /**
    * The default port the server should run on.
    */
-  public static final int DEFAULT_PORT = 8080;
+  public static final int DEFAULT_PORT = 2084;
 
   /**
    * The lowest valid TCP port number.

core/src/main/java/edu/wpi/grip/core/util/SafeShutdown.java

@@ -2,6 +2,8 @@
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
+import java.util.logging.Logger;
+
 import javax.annotation.Nullable;
 
 /**
@@ -45,6 +47,7 @@ public static void exit(int statusCode, @Nullable PreSystemExitHook hook) {
         hook.run();
       }
     } finally {
+      Logger.getLogger(SafeShutdown.class.getName()).info("Exiting GRIP");
       System.exit(statusCode);
     }
 

ui/src/main/java/edu/wpi/grip/ui/Main.java

@@ -4,6 +4,7 @@
 import edu.wpi.grip.core.GripFileModule;
 import edu.wpi.grip.core.PipelineRunner;
 import edu.wpi.grip.core.events.UnexpectedThrowableEvent;
+import edu.wpi.grip.core.exception.GripServerException;
 import edu.wpi.grip.core.http.GripServer;
 import edu.wpi.grip.core.http.HttpPipelineSwitcher;
 import edu.wpi.grip.core.operations.CVOperations;
@@ -35,6 +36,8 @@
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Parent;
 import javafx.scene.Scene;
+import javafx.scene.control.Alert;
+import javafx.scene.control.ButtonType;
 import javafx.scene.image.Image;
 import javafx.scene.text.Font;
 import javafx.stage.Stage;
@@ -145,7 +148,20 @@ public void start(Stage stage) throws IOException {
     // argument is already taken. Since we have to have the server running to handle remotely
     // loading pipelines and uploading images, as well as potential HTTP publishing operations,
     // this will cause the program to exit.
-    server.start();
+    try {
+      server.start();
+    } catch (GripServerException e) {
+      logger.log(Level.SEVERE, "The HTTP server could not be started", e);
+      Alert alert = new Alert(Alert.AlertType.CONFIRMATION, "", ButtonType.YES, ButtonType.NO);
+      alert.setTitle("The HTTP server could not be started");
+      alert.setHeaderText("The HTTP server could not be started");
+      alert.setContentText(
+          "This is normally caused by the network port being used by another process.\n\n"
+              + "HTTP sources and operations will not work until GRIP is restarted. "
+              + "Continue without HTTP functionality anyway?"
+      );
+      alert.showAndWait().filter(ButtonType.NO::equals).ifPresent(bt -> SafeShutdown.exit(1));
+    }
   }
 
   public void stop() {