Added possibilities to use template in the command_line sensor (#8505)

* Added possibilities to use template in the command_line sensor

* Minor style guideline conforms

* Minor style guideline conforms

* Added new test for template rendering

* Minor style guideline conforms

* Minor style guideline conforms

* Fixed failing testcases

* Fix style violations

* fix code pretty

homeassistant/components/binary_sensor/command_line.py

@@ -46,7 +46,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
     value_template = config.get(CONF_VALUE_TEMPLATE)
     if value_template is not None:
         value_template.hass = hass
-    data = CommandSensorData(command)
+    data = CommandSensorData(hass, command)
 
     add_devices([CommandBinarySensor(
         hass, data, name, device_class, payload_on, payload_off,

homeassistant/components/sensor/command_line.py

@@ -6,12 +6,16 @@ https://home-assistant.io/components/sensor.command_line/
 """
 import logging
 import subprocess
+import shlex
+
 from datetime import timedelta
 
 import voluptuous as vol
 
 import homeassistant.helpers.config_validation as cv
 from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.helpers import template
+from homeassistant.exceptions import TemplateError
 from homeassistant.const import (
     CONF_NAME, CONF_VALUE_TEMPLATE, CONF_UNIT_OF_MEASUREMENT, CONF_COMMAND,
     STATE_UNKNOWN)
@@ -40,7 +44,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
     value_template = config.get(CONF_VALUE_TEMPLATE)
     if value_template is not None:
         value_template.hass = hass
-    data = CommandSensorData(command)
+    data = CommandSensorData(hass, command)
 
     add_devices([CommandSensor(hass, data, name, unit, value_template)], True)
 
@@ -89,20 +93,52 @@ class CommandSensor(Entity):
 class CommandSensorData(object):
     """The class for handling the data retrieval."""
 
-    def __init__(self, command):
+    def __init__(self, hass, command):
         """Initialize the data object."""
-        self.command = command
         self.value = None
+        self.hass = hass
+        self.command = command
 
     def update(self):
         """Get the latest data with a shell command."""
-        _LOGGER.info("Running command: %s", self.command)
+        command = self.command
+        cache = {}
 
+        if command in cache:
+            prog, args, args_compiled = cache[command]
+        elif ' ' not in command:
+            prog = command
+            args = None
+            args_compiled = None
+            cache[command] = (prog, args, args_compiled)
+        else:
+            prog, args = command.split(' ', 1)
+            args_compiled = template.Template(args, self.hass)
+            cache[command] = (prog, args, args_compiled)
+
+        if args_compiled:
+            try:
+                args_to_render = {"arguments": args}
+                rendered_args = args_compiled.render(args_to_render)
+            except TemplateError as ex:
+                _LOGGER.exception("Error rendering command template: %s", ex)
+                return
+        else:
+            rendered_args = None
+
+        if rendered_args == args:
+            # No template used. default behavior
+            shell = True
+        else:
+            # Template used. Construct the string used in the shell
+            command = str(' '.join([prog] + shlex.split(rendered_args)))
+            shell = True
         try:
+            _LOGGER.info("Running command: %s", command)
             return_value = subprocess.check_output(
-                self.command, shell=True, timeout=15)
+                command, shell=shell, timeout=15)
             self.value = return_value.strip().decode('utf-8')
         except subprocess.CalledProcessError:
-            _LOGGER.error("Command failed: %s", self.command)
+            _LOGGER.error("Command failed: %s", command)
         except subprocess.TimeoutExpired:
-            _LOGGER.error("Timeout for command: %s", self.command)
+            _LOGGER.error("Timeout for command: %s", command)

tests/components/binary_sensor/test_command_line.py

@@ -54,7 +54,7 @@ class TestCommandSensorBinarySensor(unittest.TestCase):
 
     def test_template(self):
         """Test setting the state with a template."""
-        data = command_line.CommandSensorData('echo 10')
+        data = command_line.CommandSensorData(self.hass, 'echo 10')
 
         entity = command_line.CommandBinarySensor(
             self.hass, data, 'test', None, '1.0', '0',
@@ -64,7 +64,7 @@ class TestCommandSensorBinarySensor(unittest.TestCase):
 
     def test_sensor_off(self):
         """Test setting the state with a template."""
-        data = command_line.CommandSensorData('echo 0')
+        data = command_line.CommandSensorData(self.hass, 'echo 0')
 
         entity = command_line.CommandBinarySensor(
             self.hass, data, 'test', None, '1', '0', None)

tests/components/sensor/test_command_line.py

@@ -52,7 +52,7 @@ class TestCommandSensorSensor(unittest.TestCase):
 
     def test_template(self):
         """Test command sensor with template."""
-        data = command_line.CommandSensorData('echo 50')
+        data = command_line.CommandSensorData(self.hass, 'echo 50')
 
         entity = command_line.CommandSensor(
             self.hass, data, 'test', 'in',
@@ -61,9 +61,20 @@ class TestCommandSensorSensor(unittest.TestCase):
         entity.update()
         self.assertEqual(5, float(entity.state))
 
+    def test_template_render(self):
+        """Ensure command with templates get rendered properly."""
+        self.hass.states.set('sensor.test_state', 'Works')
+        data = command_line.CommandSensorData(
+            self.hass,
+            'echo {{ states.sensor.test_state.state }}'
+        )
+        data.update()
+
+        self.assertEqual("Works", data.value)
+
     def test_bad_command(self):
         """Test bad command."""
-        data = command_line.CommandSensorData('asdfasdf')
+        data = command_line.CommandSensorData(self.hass, 'asdfasdf')
         data.update()
 
         self.assertEqual(None, data.value)