better handling of piped exit codes

zfs_autobackup/CmdPipe.py

@@ -17,12 +17,13 @@ class CmdPipe:
         self.readonly = readonly
         self._should_execute = True
 
-    def add(self, cmd, readonly=False, stderr_handler=None):
+    def add(self, cmd, readonly=False, stderr_handler=None, exit_handler=None):
         """adds a command to pipe"""
 
         self.items.append({
             'cmd': cmd,
-            'stderr_handler': stderr_handler
+            'stderr_handler': stderr_handler,
+            'exit_handler': exit_handler
         })
 
         if not readonly and self.readonly:
@@ -117,10 +118,15 @@ class CmdPipe:
             if eof_count == len(selectors) and done_count == len(self.items):
                 break
 
-        # ret = []
+        #close filehandles
         last_stdout.close()
         for item in self.items:
             item['process'].stderr.close()
-            # ret.append(item['process'].returncode)
+
+        #call exit handlers
+        for item in self.items:
+            if item['exit_handler'] is not None:
+                item['exit_handler'](item['process'].returncode)
+
 
         return True

zfs_autobackup/ExecuteNode.py

@@ -5,6 +5,8 @@ import subprocess
 from zfs_autobackup.CmdPipe import CmdPipe
 from zfs_autobackup.LogStub import LogStub
 
+class ExecuteError(Exception):
+    pass
 
 class ExecuteNode(LogStub):
     """an endpoint to execute local or remote commands via ssh"""
@@ -108,9 +110,20 @@ class ExecuteNode(LogStub):
                 error_lines.append(line.rstrip())
             self._parse_stderr(line, hide_errors)
 
+        # exit code hanlder
+        if valid_exitcodes is None:
+            valid_exitcodes = [0]
+
+        def exit_handler(exit_code):
+            if self.debug_output:
+                self.debug("EXIT   > {}".format(exit_code))
+
+            if (valid_exitcodes != []) and (exit_code not in valid_exitcodes):
+             raise (ExecuteError("Command '{}' return exit code '{}' (valid codes: {})".format(" ".join(cmd), exit_code, valid_exitcodes)))
+
         # add command to pipe
         encoded_cmd = self._remote_cmd(cmd)
-        p.add(cmd=encoded_cmd, readonly=readonly, stderr_handler=stderr_handler)
+        p.add(cmd=encoded_cmd, readonly=readonly, stderr_handler=stderr_handler, exit_handler=exit_handler)
 
         # return pipe instead of executing?
         if pipe:
@@ -130,21 +143,8 @@ class ExecuteNode(LogStub):
         else:
             self.debug("CMDSKIP> {}".format(p))
 
-        # execute and verify exit codes
-        if p.execute(stdout_handler=stdout_handler) and valid_exitcodes is not []:
-            if valid_exitcodes is None:
-                valid_exitcodes = [0]
-
-            item_nr=1
-            for item in p.items:
-                exit_code=item['process'].returncode
-
-                if self.debug_output:
-                    self.debug("EXIT{}  > {}".format(item_nr, exit_code))
-
-                if exit_code not in valid_exitcodes:
-                    raise (subprocess.CalledProcessError(exit_code, " ".join(item['cmd'])))
-                item_nr=item_nr+1
+        # execute and calls handlers in CmdPipe
+        p.execute(stdout_handler=stdout_handler)
 
         if return_stderr:
             return output_lines, error_lines

zfs_autobackup/ZfsDataset.py

@@ -3,6 +3,7 @@ import subprocess
 import time
 
 from zfs_autobackup.CachedProperty import CachedProperty
+from zfs_autobackup.ExecuteNode import ExecuteError
 
 
 class ZfsDataset:
@@ -250,7 +251,7 @@ class ZfsDataset:
             self.invalidate()
             self.force_exists = False
             return True
-        except subprocess.CalledProcessError:
+        except ExecuteError:
             if not fail_exception:
                 return False
             else:

zfs_autobackup/ZfsNode.py

@@ -10,6 +10,7 @@ from zfs_autobackup.Thinner import Thinner
 from zfs_autobackup.CachedProperty import CachedProperty
 from zfs_autobackup.ZfsPool import ZfsPool
 from zfs_autobackup.ZfsDataset import ZfsDataset
+from zfs_autobackup.ExecuteNode import ExecuteError
 
 
 class ZfsNode(ExecuteNode):
@@ -81,7 +82,7 @@ class ZfsNode(ExecuteNode):
 
         try:
             self.run(cmd, hide_errors=True, valid_exitcodes=[0, 1])
-        except subprocess.CalledProcessError:
+        except ExecuteError:
             return False
 
         return True