[modules/shell] Add shell module: Execute command in shell and print result

README.md

@@ -5,7 +5,7 @@
 [![Test Coverage](https://codeclimate.com/github/tobi-wan-kenobi/bumblebee-status/badges/coverage.svg)](https://codeclimate.com/github/tobi-wan-kenobi/bumblebee-status/coverage)
 [![Issue Count](https://codeclimate.com/github/tobi-wan-kenobi/bumblebee-status/badges/issue_count.svg)](https://codeclimate.com/github/tobi-wan-kenobi/bumblebee-status)
 
-**Many, many thanks to all contributors! As of now, 50 of the modules are from various contributors (!), and only 19 from myself.**
+**Many, many thanks to all contributors! As of now, 51 of the modules are from various contributors (!), and only 19 from myself.**
 
 ![Solarized Powerline](https://github.com/tobi-wan-kenobi/bumblebee-status/blob/master/screenshots/themes/powerline-solarized.png)
 

bumblebee/modules/shell.py

@@ -0,0 +1,91 @@
+# pylint: disable=C0111,R0903,W1401
+
+""" Execute command in shell and print result
+
+Few command examples:
+    'ping 1.1.1.1 -c 1 | grep -Po "(?<=time=)\d+(\.\d+)? ms"'
+    'echo "BTC=$(curl -s rate.sx/1BTC | grep -Po \"^\d+\")USD"'
+    'curl -s https://wttr.in/London?format=%l+%t+%h+%w'
+    'pip3 freeze | wc -l'
+    'any_custom_script.sh | grep arguments'
+
+Parameters:
+    * shell.command:  Command to execute
+                      Use single parentheses if evaluating anything inside
+                      For example shell.command='echo $(date +"%H:%M:%S")'
+                      But NOT shell.command="echo $(date +'%H:%M:%S')"
+                      Second one will be evaluated only once at startup
+    * shell.interval: Update interval in minutes
+                      (defaults to 1s == every bumblebee-status update)
+    * shell.async:    Run update in async mode. Won't run next thread if
+                      previous one didn't finished yet. Useful for long
+                      running scripts to avoid bumblebee-status freezes
+                      (defaults to False)
+"""
+
+import subprocess
+import threading
+
+import bumblebee.engine
+import bumblebee.input
+import bumblebee.output
+
+
+class Module(bumblebee.engine.Module):
+    def __init__(self, engine, config):
+        widget = bumblebee.output.Widget(full_text=self.get_output)
+        super(Module, self).__init__(engine, config, widget)
+
+        if self.parameter('interval'):
+            self.interval(self.parameter('interval'))
+
+        self._command = self.parameter('command')
+        self._async = bumblebee.util.asbool(self.parameter('async'))
+        if self._async:
+            self._output = 'Computing...'
+            self._current_thread = None
+        else:
+            self._output = ''
+
+        # LMB and RMB will update output regardless of timer
+        engine.input.register_callback(self, button=bumblebee.input.RIGHT_MOUSE, cmd=self.update)
+        engine.input.register_callback(self, button=bumblebee.input.LEFT_MOUSE, cmd=self.update)
+
+    def get_output(self, _):
+        return self._output
+
+    def update(self, _):
+        # if requested then run not async version and just execute command in this thread
+        if not self._async:
+            self._output = self._get_command_output_or_error(self._command)
+            return
+
+        # if previous thread didn't end yet then don't do anything
+        if self._current_thread:
+            return
+
+        # spawn new thread to execute command and pass callback method to get output from it
+        self._current_thread = threading.Thread(target=self._run_command_in_thread,
+                                                args=(self._command, self._output_function))
+        self._current_thread.start()
+
+    @staticmethod
+    def _get_command_output_or_error(command):
+        try:
+            command_output = subprocess.check_output(command,
+                                                     shell=True,
+                                                     stderr=subprocess.STDOUT)
+            return command_output.decode('utf-8').strip()
+        except subprocess.CalledProcessError as exception:
+            exception_output = exception.output.decode('utf-8').replace('\n', '')
+            return 'Status:{} output:{}'.format(exception.returncode, exception_output)
+
+    def _run_command_in_thread(self, command, output_callback):
+        output_callback(self._get_command_output_or_error(command))
+
+    def _output_function(self, text):
+        self._output = text
+        # clear this thread data, so next update will spawn a new one
+        self._current_thread = None
+
+# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4