Added 'getHSMFileSystemFreeSpace()' method.

Signed-off-by: Cristiano Urban <cristiano.urban@inaf.it>

transfer_service/tape_client.py

@@ -16,6 +16,7 @@ from config import Config
 from exceptions import ScpInvalidFileException
 from exceptions import TapeClientException
 from redis_log_handler import RedisLogHandler
+from system_utils import SystemUtils
 
 
 class TapeClient(object):
@@ -40,6 +41,7 @@ class TapeClient(object):
         self.client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
         self.keyFile = keyFile
         self.scp = None
+        self.systemUtils = SystemUtils()
         self.HSMFilesystemList = []
 
     def connect(self):
@@ -91,6 +93,23 @@ class TapeClient(object):
             else:
                 raise TapeClientException(cmd, exitCode, stderr)
 
+    def getHSMFileSystemFreeSpace(self, HSMFilesystem):
+        "Returns the free space in bytes for a given HSM filesystem."
+        cmd = f"{self.DSMDF} -detail {HSMFilesystem} | grep "Free Size" | awk '{ print $3 }'"
+        try:
+            stdin, stdout, stderr = self.client.exec_command(cmd)
+        except Exception:
+            self.logger.exception(f"Unable to execute command: '{cmd}'")
+            raise
+        else:
+            exitCode = stdout.channel.recv_exit_status()
+            if not exitCode:
+                result = stdout.readlines()[0].rstrip('\n') + " KB"
+                freeSpace = self.systemUtils.convertSizeToBytes(result)
+                return freeSpace
+            else:
+                raise TapeClientException(cmd, exitCode, stderr)
+
     def migrate(self, fileList, tapeHSMFilesystem, jobId):
         """
         Migrates to tape all files whose absolute path is