Merge 75e1b2e into a86ad4b

.gitignore

@@ -67,3 +67,6 @@ target/
 
 # rope files
 .ropeproject/*
+
+# GreenPiThumb wiring configuration file
+wiring_config.ini

README.md

@@ -30,6 +30,7 @@ cd ..
 git clone https://github.com/JeetShetty/GreenPiThumb.git
 cd GreenPiThumb
 sudo pip install -r requirements.txt
+cp greenpithumb/wiring_config.ini.example greenpithumb/wiring_config.ini
 ```
 
 ### Dev Installation
@@ -48,4 +49,5 @@ git clone https://github.com/JeetShetty/GreenPiThumb.git
 cd GreenPiThumb
 sudo pip install -r requirements.txt
 sudo pip install -r dev_requirements.txt
+cp greenpithumb/wiring_config.ini.example greenpithumb/wiring_config.ini
 ```

greenpithumb/greenpithumb.py

@@ -6,12 +6,14 @@
 import light_sensor
 import moisture_sensor
 import temperature_sensor
+import wiring_config_parser
 
 
 class SensorHarness(object):
     """Simple container for GreenPiThumbs that polls their values and prints."""
 
-    def __init__(self):
+    def __init__(self, wiring_config):
+        # TODO(mtlynch): Hook wiring_config up to components that depend on it.
         self._adc = fake_sensors.FakeAdc(light_start=500.0,
                                          moisture_start=600.0)
         self._light_sensor = light_sensor.LightSensor(self._adc)
@@ -38,8 +40,13 @@ def print_readings(self):
                                       temperature_reading, humidity_reading)
 
 
+def read_wiring_config(config_filename):
+    with open(config_filename) as config_file:
+        return wiring_config_parser.parse(config_file.read())
+
+
 def main(args):
-    sensor_harness = SensorHarness()
+    sensor_harness = SensorHarness(read_wiring_config(args.config_file))
     sensor_harness.print_readings_header()
     while True:
         sensor_harness.print_readings()
@@ -55,4 +62,8 @@ def main(args):
                         type=float,
                         help='Number of seconds between each sensor poll',
                         default=0.5)
+    parser.add_argument('-c',
+                        '--config_file',
+                        help='Wiring config file',
+                        default='wiring_config.ini')
     main(parser.parse_args())

greenpithumb/wiring_config.ini.example

@@ -0,0 +1,15 @@
+# gpio_pins section maps which GreenPiThumb component is connected to which
+# Raspberry Pi GPIO pin (in BCM numbering).
+[gpio_pins]
+pump: 26
+dht11: 21
+mcp3008_clk: 18
+mcp3008_dout: 23
+mcp3008_din: 24
+mcp3008_cs_shdn: 25
+
+# adc_channels section maps which GreenPiThumb component is connected to which
+# channel of the MCP3008 ADC.
+[adc_channels]
+soil_moisture_sensor: 0
+light_sensor: 6

greenpithumb/wiring_config_parser.py

@@ -0,0 +1,233 @@
+import ConfigParser
+import io
+
+
+class Error(Exception):
+    pass
+
+
+class InvalidConfigError(Error):
+    """Indicates an error parsing a GreenPiThumb wiring config."""
+    pass
+
+
+class IllegalGpioPinNumberError(Error):
+    """Indicates an attempt to parse a GPIO pin with an invalid value."""
+
+
+class IllegalAdcChannelError(Error):
+    """Indicates an attempt to parse an ADC channel with an invalid value."""
+
+
+class DuplicateGpioPinNumberError(Error):
+    """Indicates an attempt to parse a GPIO pin with an invalid value."""
+
+
+class DuplicateAdcChannelError(Error):
+    """Indicates an attempt to parse an ADC channel with an invalid value."""
+
+
+class _GpioPinConfig(object):
+    """Represents GreenPiThumb's Rapsberry Pi GPIO pin configuration."""
+
+    def __init__(self, pump, dht11, mcp3008_clk, mcp3008_dout, mcp3008_din,
+                 mcp3008_cs_shdn):
+        self._pump = pump
+        self._dht11 = dht11
+        self._mcp3008_clk = mcp3008_clk
+        self._mcp3008_dout = mcp3008_dout
+        self._mcp3008_din = mcp3008_din
+        self._mcp3008_cs_shdn = mcp3008_cs_shdn
+
+    @property
+    def pump(self):
+        return self._pump
+
+    @property
+    def dht11(self):
+        return self._dht11
+
+    @property
+    def mcp3008_clk(self):
+        return self._mcp3008_clk
+
+    @property
+    def mcp3008_dout(self):
+        return self._mcp3008_dout
+
+    @property
+    def mcp3008_din(self):
+        return self._mcp3008_din
+
+    @property
+    def mcp3008_cs_shdn(self):
+        return self._mcp3008_cs_shdn
+
+
+def _validate_gpio_pin_config(gpio_config):
+    """Validates a GPIO pin configuration.
+
+    Args:
+        gpio_config: The GPIO configuration object to validate.
+
+    Raises:
+        DuplicateGpioPinNumberError when the same GPIO pin is assigned to
+            multiple components.
+    """
+    used_pins = set()
+    for pin in [gpio_config.pump, gpio_config.dht11, gpio_config.mcp3008_clk,
+                gpio_config.mcp3008_dout, gpio_config.mcp3008_din,
+                gpio_config.mcp3008_cs_shdn]:
+        if pin in used_pins:
+            raise DuplicateGpioPinNumberError(
+                'GPIO pin cannot be assigned to multiple components: %d' % pin)
+        used_pins.add(pin)
+
+
+class _AdcChannelConfig(object):
+    """Represents GreenPiThumb's ADC channel configuration."""
+
+    def __init__(self, soil_moisture_sensor, light_sensor):
+        self._soil_moisture_sensor = soil_moisture_sensor
+        self._light_sensor = light_sensor
+
+    @property
+    def soil_moisture_sensor(self):
+        return self._soil_moisture_sensor
+
+    @property
+    def light_sensor(self):
+        return self._light_sensor
+
+
+def _validate_adc_channel_config(adc_config):
+    """Validates an ADC channel configuration.
+
+    Args:
+        adc_config: The ADC channel configuration to validate
+
+    Raises:
+        DuplicateAdcChannelError when the same ADC channel is assigned to
+            multiple components.
+    """
+    if adc_config.soil_moisture_sensor == adc_config.light_sensor:
+        raise DuplicateAdcChannelError(
+            'Soil moisture sensor and light sensor cannot have the same ADC '
+            'channel: %d' % adc_config.soil_moisture_sensor)
+
+
+class _WiringConfig(object):
+    """Represents GreenPiThumb's wiring configuration."""
+
+    def __init__(self, gpio_pin_config, adc_channel_config):
+        self._gpio_pin_config = gpio_pin_config
+        self._adc_channel_config = adc_channel_config
+
+    @property
+    def gpio_pins(self):
+        return self._gpio_pin_config
+
+    @property
+    def adc_channels(self):
+        return self._adc_channel_config
+
+
+def _parse_gpio_pin(pin_raw):
+    """Parses a GPIO pin value from the configuration file.
+
+    Parses a GPIO pin value. Must be a valid Raspberry Pi GPIO pin number. Must
+    be a value from 2 to 27.
+
+    Args:
+        pin_raw: The raw GPIO pin value from the configuration file.
+
+    Returns:
+        The parsed GPIO pin value as an int.
+
+    Raises:
+        IllegalGpioPinNumberError when the value is invalid.
+    """
+    try:
+        pin = int(pin_raw)
+    except ValueError:
+        raise IllegalGpioPinNumberError(
+            'Invalid GPIO pin: %s. Pin must be a value from 2 to 27. '
+            'Be sure to use BCM numbering, not BOARD numbering.' % pin_raw)
+    if not (2 <= pin <= 27):
+        raise IllegalGpioPinNumberError(
+            'Invalid GPIO pin: %s. Pin must be a value from 2 to 27. '
+            'Be sure to use BCM numbering, not BOARD numbering.' % pin_raw)
+    return pin
+
+
+def _parse_adc_channel(channel_raw):
+    """Parses an ADC channel value from the configuration file.
+
+    Parses an ADC channel value. Must be a value from 0 to 7.
+
+    Args:
+        channel_raw: The raw ADC channel value from the configuration file.
+
+    Returns:
+        The parsed channel value as an int.
+
+    Raises:
+        IllegalAdcChannelError when the value is invalid.
+    """
+    try:
+        channel = int(channel_raw)
+    except ValueError:
+        raise IllegalAdcChannelError(
+            'Invalid ADC channel: %s. Channel must be a value from 0 to 7.' %
+            channel_raw)
+    if not (0 <= channel <= 7):
+        raise IllegalAdcChannelError(
+            'Invalid ADC channel: %s. Channel must be a value from 0 to 7.' %
+            channel_raw)
+    return channel
+
+
+def parse(config_data):
+    """Parse GreenPiThumb wiring configuration from text.
+
+    Given the contents of a GreenPiThumb wiring configuration file, parses
+    the configuration into a wiring config object.
+
+    Args:
+        config_data: The contents of a GreenPiThumb configuration file.
+
+    Returns:
+        A wiring configuration object with the following properties:
+            * gpio_pins.pump
+            * gpio_pins.dht11
+            * gpio_pins.mcp3008_clk
+            * gpio_pins.mcp3008_dout
+            * gpio_pins.mcp3008_din
+            * gpio_pins.mcp3008_cs_shdn
+            * adc_channels.soil_moisture_sensor
+            * adc_channels.light_sensor
+    """
+    raw_parser = ConfigParser.RawConfigParser()
+    try:
+        raw_parser.readfp(io.BytesIO(config_data))
+        gpio_pin_config = _GpioPinConfig(
+            pump=_parse_gpio_pin(raw_parser.get('gpio_pins', 'pump')),
+            dht11=_parse_gpio_pin(raw_parser.get('gpio_pins', 'dht11')),
+            mcp3008_clk=_parse_gpio_pin(raw_parser.get('gpio_pins',
+                                                       'mcp3008_clk')),
+            mcp3008_din=_parse_gpio_pin(raw_parser.get('gpio_pins',
+                                                       'mcp3008_din')),
+            mcp3008_dout=_parse_gpio_pin(raw_parser.get('gpio_pins',
+                                                        'mcp3008_dout')),
+            mcp3008_cs_shdn=_parse_gpio_pin(raw_parser.get('gpio_pins',
+                                                           'mcp3008_cs_shdn')))
+        _validate_gpio_pin_config(gpio_pin_config)
+        adc_channel_config = _AdcChannelConfig(
+            soil_moisture_sensor=_parse_adc_channel(raw_parser.get(
+                'adc_channels', 'soil_moisture_sensor')),
+            light_sensor=_parse_adc_channel(raw_parser.get('adc_channels',
+                                                           'light_sensor')))
+        _validate_adc_channel_config(adc_channel_config)
+        return _WiringConfig(gpio_pin_config, adc_channel_config)
+    except ConfigParser.Error as ex:
+        raise InvalidConfigError('Failed to parse wiring config', ex)