From 2ccb1683ba00a55991970af75240fd064e819fc5 Mon Sep 17 00:00:00 2001
From: Sneha Vijayarajan <sneha.vijayarajan@gmail.com>
Date: Tue, 1 Oct 2019 17:38:11 -0700
Subject: [PATCH] HADOOP-16578 : Avoid FileSystem API calls when FileSystem
 already exists

---
 .../org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java  | 3 ++-
 .../apache/hadoop/fs/azurebfs/ITestGetNameSpaceEnabled.java | 6 ++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java b/hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java
index 1663ed9b9be..82a38a23387 100644
--- a/hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java
+++ b/hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java
@@ -55,6 +55,7 @@
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.PathIOException;
+import org.apache.hadoop.fs.azurebfs.constants.AbfsHttpConstants;
 import org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations;
 import org.apache.hadoop.fs.azurebfs.constants.FileSystemUriSchemes;
 import org.apache.hadoop.fs.azurebfs.contracts.exceptions.AbfsRestOperationException;
@@ -107,7 +108,7 @@ public void initialize(URI uri, Configuration configuration)
     this.setWorkingDirectory(this.getHomeDirectory());
 
     if (abfsConfiguration.getCreateRemoteFileSystemDuringInitialization()) {
-      if (!this.fileSystemExists()) {
+      if (this.tryGetFileStatus(new Path(AbfsHttpConstants.ROOT_PATH)) == null) {
         try {
           this.createFileSystem();
         } catch (AzureBlobFileSystemException ex) {
diff --git a/hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestGetNameSpaceEnabled.java b/hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestGetNameSpaceEnabled.java
index 12157568dd2..a7d1af8d977 100644
--- a/hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestGetNameSpaceEnabled.java
+++ b/hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestGetNameSpaceEnabled.java
@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.fs.azurebfs;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.UUID;
 
@@ -25,6 +26,7 @@
 import org.junit.Test;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.azurebfs.contracts.exceptions.AbfsRestOperationException;
 import org.apache.hadoop.fs.azurebfs.services.AuthType;
 
@@ -68,12 +70,12 @@ public void testFailedRequestWhenFSNotExist() throws Exception {
             + testUri.substring(testUri.indexOf("@"));
     final AzureBlobFileSystem fs = this.getFileSystem(nonExistingFsUrl);
 
-    intercept(AbfsRestOperationException.class,
+    intercept(FileNotFoundException.class,
             "\"The specified filesystem does not exist.\", 404",
         new LambdaTestUtils.VoidCallable() {
           @Override
           public void call() throws Exception {
-            fs.getIsNamespaceEnabled();
+            fs.getFileStatus(new Path("/")); // Run a dummy FS call
           }
         });
   }