put it in a class so other classes can use it

retemplate/__init__.py

@@ -203,6 +203,25 @@ def get_value(self, key):
         raise RetrievalError
 
 
+class ProcessExecutor():
+    '''
+    A simple class to encapsulate the execution of external function calls.
+    '''
+
+    def exec_process(cmd):
+        '''
+        Shells out an external process and gets the stdout/stderr and returncoce.
+        '''
+        logging.debug('Running command: {}'.format(cmd))
+        p = subprocess.Popen(cmd,
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.STDOUT,
+                             universal_newlines=True,
+                             shell=True)
+        output = p.communicate()[0]
+        returncode = p.returncode
+        return output, returncode
+
 class LocalExecutionStore(DataStore):
     '''
     A DataStore that issues a terminal command and uses its standard output as a template value.
@@ -226,7 +245,7 @@ def get_value(self, key, **kwargs):
             # Clean these args up a bit
             for i in range(0, len(subp_args)):
                 subp_args[i] = subp_args[i].strip()
-            output, _ = self.exec_process(' '.join(subp_args))
+            output, _ = ProcessExecutor.exec_process(' '.join(subp_args))
             return output
         except Exception as ex:
             logging.error('Failed to get local execution data. Error: {}'.format(ex))
@@ -365,20 +384,6 @@ def process(self, tpl):
                 prerender.append(line)
         return '\n'.join(prerender)
 
-    def exec_process(self, cmd):
-        '''
-        Shells out an external process and gets the stdout/stderr and returncoce.
-        '''
-        logging.debug('Running command: {}'.format(cmd))
-        p = subprocess.Popen(cmd,
-                             stdout=subprocess.PIPE,
-                             stderr=subprocess.STDOUT,
-                             universal_newlines=True,
-                             shell=True)
-        output = p.communicate()[0]
-        returncode = p.returncode
-        return output, returncode
-
     def render(self):
         '''
         Renders a template in three phases:
@@ -450,7 +455,7 @@ def write_file(self, content):
                 shutil.chown(self.target, user=owner, group=group)
             if chmod:
                 logging.info('Setting mode of {} to {}'.format(self.target, chmod))
-                self.exec_process(' '.join([ 'chmod', self.settings['chmod'], self.target ]))
+                ProcessExecutor.exec_process(' '.join([ 'chmod', self.settings['chmod'], self.target ]))
             return True
         except IOError:
             logging.error('Cannot write target file {}'.format(self.target))
@@ -470,7 +475,7 @@ def execute_onchange(self):
 
         logging.info('Running onchange command \'{}\' for target {}'.format(onchange, self.target))
         try:
-            output, returncode = self.exec_process(onchange)
+            output, returncode = ProcessExecutor.exec_process(onchange)
             logging.debug('onchange command exited: {}'.format(returncode))
             logging.debug('onchange command output: {}'.format(output))
         except subprocess.CalledProcessError as ex: