proper logging, add signal handler for graceful termination

influx.py

@@ -21,6 +21,7 @@
 # *****************************************************************************
 import re
 import time
+import logging
 from datetime import datetime, timezone
 from math import floor, ceil
 
@@ -192,8 +193,7 @@ class InfluxDBWrapper:
         self.add_new_bucket(self._bucket, access == 'create')
         self._write_buffer = []
         self._alias = {}
-        print('InfluxDBWrapper', self._url, self._org, self._bucket)
-        self.debug = False
+        logging.info('InfluxDBWrapper %s %s %s', self._url, self._org, self._bucket)
 
     def enable_write_access(self):
         self._write_api_write = self._client.write_api(write_options=SYNCHRONOUS).write
@@ -356,22 +356,21 @@ class InfluxDBWrapper:
             msg.append(f'''|> keep(columns:["{'","'.join(columns + keylist)}"])''')
 
         msg = '\n'.join(msg)
-        if self.debug:
-            print(msg)
+        logging.debug('MSG %r', msg)
         self.msg = msg
 
         try:
             reader = self._client.query_api().query_csv(msg)
-        except Exception:
-            print(msg)
+        except Exception as e:
+            logging.exception("error in query: %r", msg)
             raise
 
-        if self.debug:
-            def readdebug(reader):
-                for row in reader:
-                    print(row)
-                    yield row
-            reader = readdebug(reader)
+        # if self.debug:
+        #     def readdebug(reader):
+        #         for row in reader:
+        #             print(row)
+        #             yield row
+        #     reader = readdebug(reader)
         try:
             row = next(reader)
         except StopIteration:
@@ -416,7 +415,7 @@ class InfluxDBWrapper:
             # consume unused rows
             consumed = sum(1 for _ in rows)
             if consumed:
-                print('skip', consumed, 'rows')
+                logging.info('skip %r rows', consumed)
             if not row:  # reader is at end
                 return