add try counts and increase time interval

pkg/R/sparkR.R

@@ -90,7 +90,8 @@ sparkR.init <- function(
   sparkExecutorEnv = list(),
   sparkJars = "",
   sparkRLibDir = "",
-  sparkRBackendPort = 12345) {
+  sparkRBackendPort = 12345,
+  sparkRRetryCount = 6) {
 
   if (exists(".sparkRjsc", envir = .sparkREnv)) {
     cat("Re-using existing Spark Context. Please stop SparkR with sparkR.stop() or restart R to create a new Spark Context\n")
@@ -111,18 +112,28 @@ sparkR.init <- function(
                 args = as.character(sparkRBackendPort),
                 javaOpts = paste("-Xmx", sparkMem, sep = ""))
 
-  cat("Waiting JVM bring up ...\n")
-  while(TRUE) {
+  .sparkREnv$sparkRBackendPort <- sparkRBackendPort
+  cat("Waiting for JVM to come up...\n")
+  tries <- 0
+  while(tries < sparkRRetryCount) {
     if(!connExists(.sparkREnv)) {
-      Sys.sleep(1)
-      cat(".")
-      connectBackend("localhost", sparkRBackendPort) # Connect to it
+      Sys.sleep(2 ^ tries)
+      tryCatch({
+        connectBackend("localhost", .sparkREnv$sparkRBackendPort)
+      }, error = function(err) {
+        cat("Error in Connection, retrying...\n")
+      }, warning = function(war) {
+        cat("No Connection Found, retrying...\n")
+      })
+      tries <- tries + 1
     } else {
-      cat(" ok.\n")
+      cat("Connect ok.\n")
       break
     }
   }
-  .sparkREnv$sparkRBackendPort <- sparkRBackendPort
+  if (tries == sparkRRetryCount) {
+    stop(sprintf("Failed to connect JVM after %d tries.\n", sparkRRetryCount))
+  }
 
   if (nchar(sparkHome) != 0) {
     sparkHome <- normalizePath(sparkHome)