Added plugin

README.rst

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+******************************************************************************
+              FogLAMP South MAX31865 Async mode Plugin
+******************************************************************************
+
+This directory contains a plugin that receives readings from AM2315
+humidity/temperature sensor.
+
+Requirements:
+sudo apt-get install python3-smbus
+
+=============
+Since the plugin runs in a separate process and its shutdown is controlled by the
+central FogLAMP server, pressing CTRL-C does not terminate the process properly.
+
+

am2315async.py

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+# -*- coding: utf-8 -*-
+
+# FOGLAMP_BEGIN
+# See: http://foglamp.readthedocs.io/
+# FOGLAMP_END
+
+""" Module for AM2315 'async' type plugin """
+
+import asyncio
+import copy
+import datetime
+import json
+import uuid
+
+from foglamp.common import logger
+from foglamp.plugins.common import utils
+from foglamp.services.south import exceptions
+from foglamp.services.south.ingest import Ingest
+import smbus
+
+__author__ = "Ashwin Gopalakrishnan"
+__copyright__ = "Copyright (c) 2017 OSIsoft, LLC"
+__license__ = "Apache 2.0"
+__version__ = "${VERSION}"
+
+
+_DEFAULT_CONFIG = {
+    'plugin': {
+        'description': 'AM2315 async plugin',
+        'type': 'string',
+        'default': 'am2315async'
+    },
+    'shutdownThreshold': {
+        'description': 'Time in seconds allowed for shutdown to complete the pending tasks',
+        'type': 'integer',
+        'default': '10'
+    }
+}
+
+_LOGGER = logger.setup(__name__, level=20)
+
+
+def plugin_info():
+    """ Returns information about the plugin.
+    Args:
+    Returns:
+        dict: plugin information
+    Raises:
+    """
+
+    return {
+        'name': 'AM2315 Async plugin',
+        'version': '1.0',
+        'mode': 'async',
+        'type': 'south',
+        'interface': '1.0',
+        'config': _DEFAULT_CONFIG
+    }
+
+
+def plugin_init(config):
+    """ Initialise the plugin.
+    Args:
+        config: JSON configuration document for the South device configuration category
+    Returns:
+        handle: JSON object to be used in future calls to the plugin
+    Raises:
+    """
+    data = copy.deepcopy(config)
+
+    bus = smbus.SMBus(1)
+    _LOGGER.info('AM2315 initialized')
+    return bus
+
+
+def plugin_start(bus):
+    """ Extracts data from the sensor and returns it in a JSON document as a Python dict.
+    Available for async mode only.
+    Args:
+        handle: handle returned by the plugin initialisation call
+    Returns:
+        returns a sensor reading in a JSON document, as a Python dict, if it is available
+        None - If no reading is available
+    Raises:
+        TimeoutError
+    """
+    sensor_add      = 0x5C
+    start_add       = 0x00
+    function_code   = 0x03
+    register_number = 0x04
+    response_bytes = 8
+    attempt_threshold = 50
+    async def save_data():
+        attempt = 1
+        if bus is None:
+            return
+        try:
+            while True:
+                await asyncio.sleep(1)
+                try:
+                    try:
+                        # wake up call
+                        bus.write_i2c_block_data(sensor_add, function_code, [start_add, register_number])
+                    except Exception as e:
+                        # expected exception as sensor is sleeping
+                        pass
+                    # request data
+                    bus.write_i2c_block_data(sensor_add, function_code, [start_add, register_number])
+                    # read data
+                    sensor_response = bytearray(bus.read_i2c_block_data(sensor_add, function_code, response_bytes))
+                    # function_code=sensor_response[0]
+                    # bytes_returned=sensor_response[1]
+                    # relative_humidity_high=sensor_response[2]
+                    # relative_humidity_low=sensor_response[3]
+                    # temperature_high=sensor_response[4]
+                    # temperature_low=sensor_response[5]
+                    # crc_low=sensor_response[6]
+                    # crc_high=sensor_response[7]
+
+                    # temperature
+                    temperature= (sensor_response[4] * 256 + sensor_response[5])/10
+                    # humidity
+                    humidity= (sensor_response[2] * 256 + sensor_response[3])/10
+                    # crc
+                    crc = sensor_response[7] * 256 + sensor_response[6]
+                    # calc crc to verify
+                    calc_crc = 0xFFFF
+                    for byte in sensor_response[0:6]:
+                        calc_crc = calc_crc ^ byte
+                        for i in range(1,9):
+                            if(calc_crc & 0x01):
+                                calc_crc = calc_crc >> 1
+                                calc_crc = calc_crc ^ 0xA001
+                            else:
+                                calc_crc = calc_crc >> 1
+
+                    if calc_crc != crc:
+                        pass
+
+                    time_stamp = str(datetime.datetime.now(tz=datetime.timezone.utc))
+                    data = {
+                        'asset': 'temperature',
+                        'timestamp': time_stamp,
+                        'key': str(uuid.uuid4()),
+                        'readings': {
+                            "temperature": temperature,
+                        }
+                    }
+                    await Ingest.add_readings(asset='AM2315/{}'.format(data['asset']),
+                                                           timestamp=data['timestamp'], key=data['key'],
+                                                           readings=data['readings'])
+                    data = {
+                        'asset': 'humidity',
+                        'timestamp': time_stamp,
+                        'key': str(uuid.uuid4()),
+                        'readings': {
+                            "humidity": humidity,
+                        }
+                    }
+                    await Ingest.add_readings(asset='AM2315/{}'.format(data['asset']),
+                                                           timestamp=data['timestamp'], key=data['key'],
+                                                           readings=data['readings'])
+                    attempt = 1
+                except (Exception) as ex:
+                    attempt += 1
+                    if attempt > attempt_threshold:
+                        raise RuntimeError("Attempt {} exceeds attempt threshold of {}".format(attempt, attempt_threshold))
+        except (Exception, RuntimeError, pexpect.exceptions.TIMEOUT) as ex:
+            _LOGGER.exception("AM2315 async exception: {}".format(str(ex)))
+            raise exceptions.DataRetrievalError(ex)
+        _LOGGER.debug("AM2315 async reading: {}".format(json.dumps(data)))
+        return
+    asyncio.ensure_future(save_data())
+
+
+def plugin_reconfigure(handle, new_config):
+    """ Reconfigures the plugin
+
+    it should be called when the configuration of the plugin is changed during the operation of the South device service;
+    The new configuration category should be passed.
+
+    Args:
+        handle: handle returned by the plugin initialisation call
+        new_config: JSON object representing the new configuration category for the category
+    Returns:
+        new_handle: new handle to be used in the future calls
+    Raises:
+    """
+    _LOGGER.info("Old config for AM2315 plugin {} \n new config {}".format(handle, new_config))
+
+    # Find diff between old config and new config
+    diff = utils.get_diff(handle, new_config)
+
+    # TODO
+    new_handle = copy.deepcopy(new_config)
+    new_handle['restart'] = 'no'
+    return new_handle
+
+
+def _plugin_stop(handle):
+    """ Stops the plugin doing required cleanup, to be called prior to the South device service being shut down.
+
+    Args:
+        handle: handle returned by the plugin initialisation call
+    Returns:
+    Raises:
+    """
+    _LOGGER.info('AM2315 (async) Disconnected.')
+
+
+def plugin_shutdown(handle):
+    """ Shutdowns the plugin doing required cleanup, to be called prior to the South device service being shut down.
+
+    Args:
+        handle: handle returned by the plugin initialisation call
+    Returns:
+    Raises:
+    """
+    _plugin_stop(handle)
+    _LOGGER.info('AM2315 async plugin shut down.')

cmds.sql

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+--- Database commands to insert the new plugin into FogLAMP
+
+--- Create the south service instannce
+INSERT INTO foglamp.scheduled_processes ( name, script ) VALUES ( 'AM2315',   '["services/south"]' );
+
+--- Add the schedule to start the service at system startup
+INSERT INTO foglamp.schedules ( id, schedule_name, process_name, schedule_type,
+                                schedule_time, schedule_interval, exclusive, enabled )
+       VALUES ( '56450027-824e-417b-a5d3-0f9a4211aaa5', -- id
+                'AM2315 async south',                 -- schedule_name
+                'AM2315',                             -- process_name
+                1,                                      -- schedule_type (startup)
+                NULL,                                   -- schedule_time
+                '00:00:00',                             -- schedule_interval
+                true,                                   -- exclusive
+                true                                    -- enabled
+              );
+
+--- Insert the config needed to load the plugin
+INSERT INTO foglamp.configuration ( key, description, value )
+    VALUES ( 'AM2315',
+             'AM2315 async South Plugin',
+             ' { "plugin" : { "type" : "string", "value" : "am2315async", "default" : "am2315async", "description" : "Python module name of the plugin to load" } } '
+           );
+