IMPALA-12471 PART-2: Add check for mysqld socket file

This patch adds a check for the existance of mysqld.sock
file in directory: /var/run/mysqld/ inside the mysqld
docker container. If the file is not present then the
test is skipped.

Testing: tested manually with and without the mysqld.sock
file.

Change-Id: I393fd03fa6efd4c11781d219f66978a4f556c668
Reviewed-on: http://gerrit.cloudera.org:8080/20780
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>

testdata/bin/setup-mysql-env.sh

@@ -53,6 +53,13 @@ if [ $mysqld_status = "stopped" ];then
   exit 2
 fi
 
+# Check if mysqld.sock exists
+if [ $(docker exec -i mysql ls /var/run/mysqld/mysqld.sock > /dev/null 2>&1;\
+echo $?) -gt 0 ]; then
+  echo "Error: File /var/run/mysqld/mysqld.sock not found"
+  exit 30
+fi
+
 # Add permission to mysql socket file
 docker exec -i mysql chmod 777 /var/run/mysqld/mysqld.sock
 

tests/custom_cluster/test_ext_data_sources.py

@@ -81,6 +81,8 @@ class TestMySqlExtJdbcTables(CustomClusterTestSuite):
         pytest.skip("These tests requireadd the docker to be added to sudoer's group")
       elif e.returncode == 20:
         pytest.skip("Can't connect to local MySQL server")
+      elif e.returncode == 30:
+        pytest.skip("File /var/run/mysqld/mysqld.sock not found")
       else:
         assert False, "Failed to setup MySQL testing environment"