Change behaviour of the EI backendInstancesinformation file (#99)

- EI will now use user.home as default place
  to create ".eiffel-intelligent-home" folder with
  EIBackendInstancesInformation.json as default name. If it doesnt exist
  it it will try to create it and if it cannot create it, it will
  exit. If backendInstancesFilePath is given in application.properties
  that will be used instead, if it doesnt exist it will be created.
  If it can't be created it will exit.

Author: erik-edling

src/main/java/com/ericsson/ei/frontend/utils/BackEndInstanceFileUtils.java

@@ -22,16 +22,32 @@
 public class BackEndInstanceFileUtils {
 
     private static final Logger LOG = LoggerFactory.getLogger(BackEndInstanceFileUtils.class);
-    private static final String PATH_TO_WRITE = "src/main/resources/EIBackendInstancesInformation.json";
 
-    @Value("${ei.backendInstancesPath:#{null}}")
+    private static final String BACKEND_INSTANCES_DEFAULT_FILENAME = "EIBackendInstancesInformation.json";
+    private static final String EI_HOME_DEFAULT_NAME = ".eiffel-intelligence-frontend";
+
     private String eiInstancesPath;
 
+    @Value("${ei.backendInstancesFilePath:#{null}}")
+    private String backendInstancesFilePath;
+
     @PostConstruct
-    public void init() {
+    public void init() throws IOException {
         LOG.info("Initiating BackEndInstanceFileUtils.");
-        if (eiInstancesPath == null || eiInstancesPath.isEmpty()) {
-            setEiInstancesPath(PATH_TO_WRITE);
+
+        // Use home folder if a specific backendInstancesFilePath isn't provided
+        if(backendInstancesFilePath == null || backendInstancesFilePath.isEmpty()) {
+            String homeFolder = System.getProperty("user.home");
+            String eiHome = Paths.get(homeFolder, EI_HOME_DEFAULT_NAME).toString();
+
+            Boolean eiHomeExists = Files.isDirectory(Paths.get(eiHome));
+            if (!eiHomeExists) {
+                createEiHomeFolder(eiHome);
+            }
+
+            setEiInstancesPath(Paths.get(eiHome, BACKEND_INSTANCES_DEFAULT_FILENAME).toString());
+        } else {
+            setEiInstancesPath(Paths.get(backendInstancesFilePath).toString());
         }
     }
 
@@ -70,16 +86,35 @@ public void dumpJsonArray(JsonArray jsonArrayToDump) {
     }
 
     private void ensureValidFile() throws IOException {
-        if (!(new File(eiInstancesPath).isFile())) {
-            LOG.error("File does not exist! Trying to creat file.");
-            Files.createFile(Paths.get(eiInstancesPath));
-            Files.write(Paths.get(eiInstancesPath), "[]".getBytes());
-            return;
+        try {
+            if (!(new File(eiInstancesPath).isFile())) {
+                createFileWithDirs();
+                return;
+            }
+
+            if (!fileContainsJsonArray()) {
+                LOG.error("File does not contain valid json! JSON:'" + new String(Files.readAllBytes(Paths.get(eiInstancesPath))) + "'.");
+                System.exit(-1);
+            }
+        } catch(Exception e) {
+            String message = String.format(
+                    "Failed to read backendInstancesFilePath %s. Please check access rights or choose another backendInstancesFilePath in application.properties.", eiInstancesPath);
+            LOG.error(message);
+            System.exit(-1);
         }
+    }
 
-        if (!fileContainsJsonArray()) {
-            LOG.error("File does not contain valid json! JSON:'" + new String(Files.readAllBytes(Paths.get(eiInstancesPath))) + "'.");
+    private void createFileWithDirs() throws IOException {
+        File eiInstancesParentFolder = Paths.get(eiInstancesPath).getParent().toFile();
+
+        if (!(eiInstancesParentFolder.isDirectory())){
+            LOG.info(String.format("Parentdir(s) for %s does not exist! Trying to create necessary parent dirs.", backendInstancesFilePath));
+            eiInstancesParentFolder.mkdirs();
         }
+
+        LOG.info("File does not exist! Trying to create file.");
+        Files.createFile(Paths.get(eiInstancesPath));
+        Files.write(Paths.get(eiInstancesPath), "[]".getBytes());
     }
 
     private boolean fileContainsJsonArray() {
@@ -92,4 +127,15 @@ private boolean fileContainsJsonArray() {
         }
     }
 
+    private void createEiHomeFolder(String eiHome) throws IOException {
+        Boolean success = (new File(eiHome)).mkdirs();
+
+        if (!success) {
+            String message = String.format(
+                    "Failed to create eiffel intelligence home folder in %s. Please check access rights or choose a specific backendInstancesFilePath in application.properties.", eiHome);
+            LOG.error(message);
+            System.exit(-1);
+        }
+    }
+
 }

src/main/resources/application.properties

@@ -22,7 +22,7 @@ ei.backendServerHost=localhost
 ei.backendServerPort=8090
 ei.backendContextPath=
 ei.useSecureHttpBackend=false
-ei.backendInstancesPath=
+ei.backendInstancesFilePath=
 
 ###### EI Documentation Link Url ##########
 ei.eiffelDocumentationUrls={ "EI Frontend GitHub": "https://github.com/eiffel-community/eiffel-intelligence-frontend",\