New way of working for checking if the system user running pg_activit…

…y has enough rights in Data.pg_is_local_access(): retreive instance PID file through pg_settings view, open the file and get its content which is the postmasters's PID and finally try to fetch IO counters for this process. Thanks to Julien Rouhaud for the idea.

pgactivity/Data.py

@@ -174,26 +174,27 @@ def pg_connect(self,
     def pg_is_local_access(self,):
         """
         Verify if the user running pg_activity can acces 
-        system informations for a postgres process.
+        system informations for the postmaster process.
         """
-        for psproc in psutil.process_iter():
-            try:
-                name = psproc.name()
-            except NameError:
-                name = psproc.name
-            except TypeError:
-                name = psproc.name
-            if name in ('postgres', 'postmaster', 'edb-postgres'):
+        try:
+            query = "SELECT setting AS pid_file FROM pg_settings WHERE name = 'external_pid_file'"
+            cur = self.pg_conn.cursor()
+            cur.execute(query)
+            ret = cur.fetchone()
+            pid_file = ret['pid_file']
+            with open(pid_file, 'r') as fd:
+                pid = fd.read().strip()
                 try:
-                    proc = PSProcess(psproc.pid)
+                    proc = PSProcess(int(pid))
                     proc.io_counters()
                     proc.cpu_times()
                     return True
                 except psutil.AccessDenied:
                     return False
                 except Exception:
                     return False
-        return False
+        except Exception:
+            return False
 
     def pg_get_version(self,):
         """