monitor: add promise executor

stack/monitor/run-promise.py

+#!{{ python_executable }}
+# -*- coding: utf-8 -*-
+
+import sys
+import os
+import subprocess
+import json
+from cStringIO import StringIO
+
+def main():
+  if len(sys.argv) < 4:
+    print("Usage: %s <pid_path> <output_path> <command...>" % sys.argv[0])
+    return 2
+  pid_path=sys.argv[1]
+  output_path=sys.argv[2]
+  if os.path.exists(pid_path):
+    with open(pid_path, "r") as pidfile:
+      try:
+        pid = int(pidfile.read(6))
+      except ValueError:
+        pid = None
+      if pid and os.path.exists("/proc/" + str(pid)):
+        print("A process is already running with pid " + str(pid))
+        return 1
+  with open(pid_path, "w") as pidfile:
+    process = executeCommand(sys.argv[3:])
+    pidfile.write(str(process.pid))
+  status_json = generateStatusJsonFromProcess(process)
+  with open(output_path, "w") as outputfile:
+    json.dump(status_json, outputfile)
+  os.remove(pid_path)
+
+
+def generateStatusJsonFromProcess(process):
+  stdout, stderr = process.communicate()
+  try:
+    status_json = json.loads(stdout)
+  except ValueError:
+    status_json = {}
+  if process.returncode != 0:
+    status_json["status"] = "error"
+  elif not status_json.get("status"):
+    status_json["status"] = "OK"
+  if stderr:
+    status_json["error"] = stderr
+  return status_json
+
+
+def executeCommand(args):
+  return subprocess.Popen(
+    args,
+    #cwd=instance_path,
+    #env=None if sys.platform == 'cygwin' else {},
+    stdin=None,
+    stdout=subprocess.PIPE,
+    stderr=subprocess.PIPE
+  )
+
+
+if __name__ == "__main__":
+  sys.exit(main())