ZEPPELIN-143: adding JGit as initial impl

zeppelin-zengine/pom.xml

@@ -51,13 +51,13 @@
       <artifactId>zeppelin-interpreter</artifactId>
       <version>${project.version}</version>
     </dependency>
-	
+
 	<dependency>
       <groupId>com.amazonaws</groupId>
       <artifactId>aws-java-sdk-s3</artifactId>
       <version>1.10.1</version>
 	</dependency>
-    
+
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
@@ -123,12 +123,6 @@
       <artifactId>guava</artifactId>
     </dependency>
 
-    <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <scope>test</scope>
-    </dependency>
-
     <dependency>
       <groupId>org.reflections</groupId>
       <artifactId>reflections</artifactId>
@@ -151,11 +145,24 @@
       <version>1.4.01</version>
     </dependency>
 
+    <dependency>
+      <groupId>org.eclipse.jgit</groupId>
+      <artifactId>org.eclipse.jgit</artifactId>
+      <version>4.1.1.201511131810-r</version>
+    </dependency>
+
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-all</artifactId>
       <version>1.9.0</version>
       <scope>test</scope>
-    </dependency>    
+    </dependency>
+
   </dependencies>
 </project>

zeppelin-zengine/src/main/java/org/apache/zeppelin/notebook/repo/GitNotebookRepo.java

@@ -22,6 +22,11 @@ import java.util.List;
 
 import org.apache.zeppelin.conf.ZeppelinConfiguration;
 import org.apache.zeppelin.notebook.Note;
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.internal.storage.file.FileRepository;
+import org.eclipse.jgit.lib.Repository;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * NotebookRepo that hosts all the notebook FS in a single Git repo
@@ -29,18 +34,24 @@ import org.apache.zeppelin.notebook.Note;
  * This impl intended to be simple and straightforward:
  *   - does not handle branches
  *   - only basic git, no Github push\pull yet
- * 
- * 
+ *
+ *
  * TODO(bzz): describe config
  *  GIT_URL remote
  *  auth credentials
  */
 public class GitNotebookRepo extends VFSNotebookRepo implements NotebookRepoVersioned {
+  private static final Logger LOG = LoggerFactory.getLogger(GitNotebookRepo.class);
 
-  // I. First usefull case: 
+  private Repository localRepo;
+  private Git git;
+
+  private String localPath;
+
+  // I. First usefull case:
   //   start \w repo + tutorial notebook
   //   all modifications results in a commit
-  
+
   // II. Next case:
   //   start \wo .git
   //   create one
@@ -48,13 +59,18 @@ public class GitNotebookRepo extends VFSNotebookRepo implements NotebookRepoVers
   //   ..and then I...
 
   // III. Next case:
-  //   start \w repo 
+  //   start \w repo
   //   show history
   //   user can switch to REV in read-only
-  
+
   public GitNotebookRepo(ZeppelinConfiguration conf) throws IOException {
     super(conf);
 
+    localPath = getRootDir().getName().getBaseName();
+    LOG.info("Opening a git repo at {}", localPath);
+    localRepo = new FileRepository(localPath  + "/.git");
+    git = new Git(localRepo);
+
     //TODO(bzz):
     // - check that ./notebooks/.git exists
     // - git init

zeppelin-zengine/src/main/java/org/apache/zeppelin/notebook/repo/VFSNotebookRepo.java

@@ -182,7 +182,7 @@ public class VFSNotebookRepo implements NotebookRepo {
     return getNote(noteDir);
   }
 
-  private FileObject getRootDir() throws IOException {
+  protected FileObject getRootDir() throws IOException {
     FileObject rootDir = fsManager.resolveFile(getPath("/"));
 
     if (!rootDir.exists()) {