run_command_at_interval

dotfiles/lib/python/run_command_at_interval.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+from optparse import OptionParser
+from subprocess import Popen, PIPE
+import select
+import sys
+import time
+
+
+class IntervallicCommandRunner(object):
+
+    def __init__(self, command, command_interval, sleep_time=1):
+        self.command = command
+        self.command_interval = command_interval
+        self.sleep_time = sleep_time
+        self.last_time = None
+        self.read_last_time = True
+
+    @property
+    def can_read_from_stdin(self):
+        return sys.stdin in select.select([sys.stdin], [], [], 0)[0]
+
+    def _accumulate_input(self):
+        time_to_stop_after = self.last_time + self.command_interval
+        lines = []
+        new_time = time.time()
+
+        while new_time < time_to_stop_after:
+            for _ in range(10):
+                if self.can_read_from_stdin:
+                    lines.append(sys.stdin.readline())
+                    break
+            else:
+                time.sleep(self.sleep_time)
+            new_time = time.time()
+
+        self.last_time = new_time
+
+        return ''.join(lines)
+
+    def loop_indefinitely(self):
+        self.last_time = time.time()
+        while True:
+            Popen([self.command], shell=True, stdin=PIPE).communicate(
+                self._accumulate_input()
+            )
+
+
+if __name__ == '__main__':
+    parser = OptionParser()
+    parser.add_option('-i', '--command-interval', dest="command_interval",
+                      action="store", type="float", default=1.0)
+    parser.add_option('-c', '--command', dest="command", action="store",
+                      default='cat')
+    options, _ = parser.parse_args()
+    IntervallicCommandRunner(options.command,
+                             options.command_interval).loop_indefinitely()