checking if projects are enabled before enabling them (#2571)

fixes #2563

Author: tulinkry

opengrok-indexer/src/main/java/org/opengrok/indexer/index/Indexer.java

@@ -307,8 +307,8 @@ public static void main(String argv[]) {
                 try {
                     IndexerUtil.enableProjects(webappURI);
                 } catch (Exception e) {
-                    LOGGER.log(Level.SEVERE, "Mis-configuration of webapp webappURI", e);
-                    System.err.println("Couldn't notify the webapp: " + e.getLocalizedMessage());
+                    LOGGER.log(Level.SEVERE, String.format("Couldn't notify the webapp on %s.", webappURI), e);
+                    System.err.println(String.format("Couldn't notify the webapp on %s: %s.", webappURI, e.getLocalizedMessage()));
                 }
             }
 

opengrok-indexer/src/main/java/org/opengrok/indexer/index/IndexerUtil.java

@@ -22,23 +22,47 @@
  */
 package org.opengrok.indexer.index;
 
+import javax.ws.rs.ProcessingException;
+import javax.ws.rs.WebApplicationException;
 import javax.ws.rs.client.ClientBuilder;
 import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.Invocation;
+import javax.ws.rs.client.ResponseProcessingException;
+import javax.ws.rs.core.Response;
 
 class IndexerUtil {
 
     private IndexerUtil() {
     }
 
-    static void enableProjects(final String host) {
-        ClientBuilder.newClient()
-                .target(host)
-                .path("api")
-                .path("v1")
-                .path("configuration")
-                .path("projectsEnabled")
-                .request()
-                .put(Entity.text(Boolean.TRUE.toString()));
+    /**
+     * Enable projects in the remote host application.
+     * <p>
+     * NOTE: performs a check if the projects are already enabled,
+     * before making the change request
+     *
+     * @param host the url to the remote host
+     * @throws ResponseProcessingException in case processing of a received HTTP response fails
+     * @throws ProcessingException         in case the request processing or subsequent I/O operation fails
+     * @throws WebApplicationException     in case the response status code of the response returned by the server is not successful
+     */
+    public static void enableProjects(final String host) throws
+            ResponseProcessingException,
+            ProcessingException,
+            WebApplicationException {
+        final Invocation.Builder request = ClientBuilder.newClient()
+                                                        .target(host)
+                                                        .path("api")
+                                                        .path("v1")
+                                                        .path("configuration")
+                                                        .path("projectsEnabled")
+                                                        .request();
+        final String enabled = request.get(String.class);
+        if (enabled == null || !Boolean.valueOf(enabled)) {
+            final Response r = request.put(Entity.text(Boolean.TRUE.toString()));
+            if (r.getStatusInfo().getFamily() != Response.Status.Family.SUCCESSFUL) {
+                throw new WebApplicationException(String.format("Unable to enable projects: %s", r.getStatusInfo().getReasonPhrase()), r.getStatus());
+            }
+        }
     }
-
 }

opengrok-indexer/src/test/java/org/opengrok/indexer/index/IndexerUtilTest.java

@@ -0,0 +1,11 @@
+package org.opengrok.indexer.index;
+
+import javax.ws.rs.ProcessingException;
+import org.junit.Test;
+
+public class IndexerUtilTest {
+    @Test(expected = ProcessingException.class)
+    public void testEnableProjectsInvalidUrl() {
+        IndexerUtil.enableProjects("http://non-existent.server.com:123");
+    }
+}