Improved handling of unavailable devices

Specifically compiled Python code and Vim swap files.

.gitignore

@@ -0,0 +1,4 @@
+__pycache__/
+*.pyc
+
+.*.sw?

README.md

@@ -1,3 +1,11 @@
+# SEM6000 Python Library
+
+SEM6000 is a energy meter and power switch with Bluetooth 4.0.
+
+This library provides a Python module for these devices
+
+## Run the example code
+
 ```
 $ git clone … sem6000
 $ cd sem6000
@@ -5,4 +13,52 @@ $ virtualenv -p python3 python3_venv
 $ . ./python3_venv/bin/activate
 $ pip3 install -r requirements.txt
 $ python3 example.py
-```
+```
+
+## Collectd Plugin
+
+You can find a Plugin for [collectd](https://collectd.org) in the `collectd`
+subdirectory.
+
+Installation procedure (the target directory may be changed of course):
+
+```shell
+# mkdir -p /usr/local/lib/collectd/python
+# cp collectd/collectd_sem6000.py /usr/local/lib/collectd/python
+# cp sem6000.py /usr/local/lib/collectd/python
+```
+
+Add or adjust the configuration for your collectd’s Python plugin as follows:
+
+```
+<Plugin python>
+  ModulePath "/usr/local/share/collectd/python"
+  LogTraces true
+  Interactive false
+  Import "collectd_sem6000"
+
+  <Module collectd_sem6000>
+    Address "12:34:56:78:90:ab"
+    SocketName "FirstSocket"
+    ReadTimeout 30
+    SuspendTime 300
+  </Module>
+  <Module collectd_sem6000>
+    Address "ab:cd:ef:13:37:42"
+    SocketName "ASecondSocket"
+  </Module>
+  # ...
+</Plugin>
+```
+
+`ReadTimeout` and `SuspendTime` control what’s happening when a device is
+unavailable. If no value could be retrieved for `ReadTimeout` seconds, the
+plugin does not retry for `SuspendTime` seconds. After that, normal operation
+is resumed. This procedure ensures that an unreachable device does not block
+other devices (too often) in the current single-threaded architecture.
+
+If not specified, `ReadTimeout` is 30 seconds and `SuspendTime` is 5 minutes.
+
+Make sure that everything listed in `requirements.txt` is available to the user
+running collectd.
+

collectd/collectd_sem6000.py

@@ -0,0 +1,144 @@
+#!/usr/bin/env python3
+# coding: utf-8
+# vim: noet ts=2 sw=2 sts=2
+
+import os
+import time
+import collectd
+
+from sem6000 import SEMSocket
+import bluepy
+
+instances = []
+
+def init_func():
+	pass
+
+def config_func(cfg):
+	global instances
+
+	config = {}
+
+	for node in cfg.children:
+		key = node.key.lower()
+		value = node.values[0]
+
+		if key in ['address', 'socketname']:
+			config[key] = value
+
+		if key == 'readtimeout':
+			config['readtimeout'] = int(value)
+
+		if key == 'suspendtime':
+			config['suspendtime'] = int(value)
+
+	if 'address' not in config.keys():
+		collectd.error('sem6000: address must be set')
+		return
+
+	if 'socketname' not in config.keys():
+		config['socketname'] = config['address'].replace(':', '')
+
+	if 'readtimeout' not in config.keys():
+		config['readtimeout'] = 30
+
+	if 'suspendtime' not in config.keys():
+		config['suspendtime'] = 300
+
+	instances.append( {
+		'config': config,
+		'socket': None,
+		'suspended': False,
+		'lastsuccess': 0,
+		'resumetime': 0
+		} )
+
+def read_func():
+	global instances
+
+	for inst in instances:
+		config = inst['config']
+
+		if inst['suspended']:
+			if time.time() < inst['resumetime']:
+				continue
+			else:
+				collectd.info("sem6000: Device {} waking up.".format(config['address']))
+				inst['suspended'] = False
+				inst['lastsuccess'] = time.time()
+
+		try:
+			if inst['socket'] == None:
+				collectd.info("sem6000: Connecting to {}...".format(config['address']))
+
+				inst['socket'] = SEMSocket(config['address'])
+				collectd.info("sem6000: Connected.")
+
+			inst['socket'].getStatus()
+		except (SEMSocket.NotConnectedException, bluepy.btle.BTLEDisconnectError, BrokenPipeError) as e:
+			collectd.warning("sem6000: Exception caught: {}".format(e))
+			collectd.warning("sem6000: Restarting on next cycle...")
+
+			if inst['lastsuccess'] < time.time() - config['readtimeout']:
+				collectd.error("sem6000: no successful communication with {} for {:.1f} seconds. Suspending device for {:.1f} seconds.".format(
+					config['address'], config['readtimeout'], config['suspendtime']))
+
+				inst['suspended'] = True
+				inst['resumetime'] = time.time() + config['suspendtime']
+
+			if inst['socket'] != None:
+				inst['socket'].disconnect()
+				inst['socket'] = None
+
+		socket = inst['socket']
+
+		if socket != None and socket.voltage != 0:
+			collectd.debug("Uploading values for {}".format(socket.mac_address))
+
+			inst['lastsuccess'] = time.time()
+
+			val = collectd.Values(plugin = 'sem6000-{}'.format(config['socketname']))
+
+			val.type = 'voltage'
+			val.type_instance = 'grid'
+			val.values = [ socket.voltage ]
+			val.dispatch()
+
+			val.type = 'current'
+			val.type_instance = 'load'
+			val.values = [ socket.current ]
+			val.dispatch()
+
+			val.type = 'power'
+			val.type_instance = 'real_power'
+			val.values = [ socket.power ]
+			val.dispatch()
+
+			val.type = 'gauge'
+			val.type_instance = 'power_factor'
+			val.values = [ socket.power_factor ]
+			val.dispatch()
+
+			val.type = 'gauge'
+			val.type_instance = 'load_on'
+			val.values = [ socket.powered ]
+			val.dispatch()
+
+			val.type = 'frequency'
+			val.type_instance = 'grid'
+			val.values = [ socket.frequency ]
+			val.dispatch()
+
+def shutdown_func():
+	global instances
+
+	for inst in instances:
+		if inst['socket'] != None:
+			inst['socket'].disconnect()
+
+	instances = []
+
+collectd.register_config(config_func)
+collectd.register_init(init_func)
+collectd.register_read(read_func)
+collectd.register_shutdown(shutdown_func)

example.py

@@ -1,23 +1,37 @@
+#!/usr/bin/env python3
+
 import time
 from sem6000 import SEMSocket
 
-# auto_reconnect_timeout enabled auto reconnect if sending a command fails. Valid values:
-# None (default): everything that fails throws NotConnectedException's
-# -1: infinite retries
-# integer: seconds before exception is thrown
+import bluepy
 
-socket = SEMSocket('f0:c7:7f:0d:e7:17', auto_reconnect_timeout=None)
-
-#socket.login("1337")
-#socket.changePassword("1234")
-#socket.login("1234")
+socket = None
 
 while True:
     time.sleep(1)
     try:
+        if socket == None:
+            print("Connecting...")
+
+            # auto_reconnect_timeout enabled auto reconnect if sending a command fails. Valid values:
+            # None (default): everything that fails throws NotConnectedException's
+            # -1: infinite retries
+            # integer: seconds before exception is thrown
+
+            socket = SEMSocket('f0:c7:7f:0d:e7:17')
+            print("Connected.")
+
+            #socket.login("1337")
+            #socket.changePassword("1234")
+            #socket.login("1234")
+
         socket.getStatus()
         socket.setStatus(True)
         print("=== {} ({}) ===".format(socket.mac_address, "on" if socket.powered else "off"))
-        print("\t{}V {}A → {}W@{}Hz".format(socket.voltage, socket.current, socket.power, socket.frequency))
-    except SEMSocket.NotConnectedException:
-        socket.reconnect(-1) #infinite reconnect attempts
+        print("\t{}V {}A → {}W@{}Hz (PF: {})".format(socket.voltage, socket.current, socket.power, socket.frequency, socket.power_factor))
+    except (SEMSocket.NotConnectedException, bluepy.btle.BTLEDisconnectError, BrokenPipeError):
+        print("Restarting...")
+        if socket != None:
+            socket.disconnect()
+            socket = None
+

sem6000.py

@@ -4,11 +4,11 @@ import uuid
 
 class SEMSocket():
     password = "0000"
-    auto_reconnect_timeout = None
     powered = False
     voltage = 0
     current = 0
     power = 0
+    power_factor = 0
     frequency = 0
     mac_address = ""
     custom_service = None
@@ -17,9 +17,8 @@ class SEMSocket():
     _notify_char = None
     _btle_device = None
 
-    def __init__(self, mac, auto_reconnect_timeout = None):
+    def __init__(self, mac):
         self.mac_address = mac
-        self.auto_reconnect_timeout = auto_reconnect_timeout
         self._btle_device = btle.Peripheral(None ,addrType=btle.ADDR_TYPE_PUBLIC,iface=0)
         try:
             self.reconnect()
@@ -80,18 +79,9 @@ class SEMSocket():
         except:
             return False
 
-    def __reconnect(self):
+    def reconnect(self):
         self.disconnect()
         self.connect()
-
-    def reconnect(self, timeout = None):
-        if timeout == None:
-            self.__reconnect()
-        else:
-            reconnect_start = time.time()
-            while abs(reconnect_start - time.time()) < timeout or timeout == -1:
-                self.__reconnect()
-
         if not self.connected:
             raise self.NotConnectedException
 
@@ -182,7 +172,7 @@ class SEMSocket():
 
         def send(self):
             if not self.__btle_device.connected:
-                self.__btle_device.reconnect(self.__btle_device.auto_reconnect_timeout)
+                self.__btle_device.reconnect()
 
             self.__btle_device._write_char.write(self.__data, True)
             self.__btle_device._btle_device.waitForNotifications(5)
@@ -204,11 +194,18 @@ class SEMSocket():
                 print("Switch toggled")
                 self.__btle_device.getStatus()
             elif message_type == 0x04: #status related data
-                self.__btle_device.voltage = data[8]
-                self.__btle_device.current = (data[9] << 8 | data[10]) / 1000
-                self.__btle_device.power = (data[5] << 16 | data[6] << 8 | data[7]) / 1000
+                voltage = data[8]
+                current = (data[9] << 8 | data[10]) / 1000
+                power   = (data[5] << 16 | data[6] << 8 | data[7]) / 1000
+
+                self.__btle_device.voltage = voltage
+                self.__btle_device.current = current
+                self.__btle_device.power   = power
                 self.__btle_device.frequency = data[11]
                 self.__btle_device.powered = bool(data[4])
+
+                # calculated values
+                self.__btle_device.power_factor = power / (voltage * current)
             elif message_type == 0x17:
                 if data[5] == 0x00 or data[5] == 0x01:
                     if data[4]: