runner: introduce function to test running process from pidfile

slapos/runner/process.py

@@ -104,3 +104,18 @@ def setHandler(sig_list=None):
     sig_list = [signal.SIGTERM]
   for sig in sig_list:
     signal.signal(sig, handler)
+
+
+def isPidFileProcessRunning(pidfile):
+  """
+  Test if the pidfile exist and if the process is still active
+  """
+  if os.path.exists(pidfile):
+    try:
+      pid = int(open(pidfile, 'r').readline())
+    except ValueError:
+      pid = None
+    # XXX This could use psutil library.
+    if pid and os.path.exists("/proc/%s" % pid):
+      return True
+    return False

slapos/runner/utils.py

@@ -20,7 +20,7 @@ from flask import jsonify
 
 from slapos.runner.gittools import cloneRepo
 
-from slapos.runner.process import Popen, isRunning, killRunningProcess
+from slapos.runner.process import Popen, isRunning, killRunningProcess, isPidFileProcessRunning
 from slapos.htpasswd import HtpasswdFile
 import slapos.slap
 
@@ -278,6 +278,8 @@ def runSoftwareWithLock(config, lock=True):
     return False
 
   slapgrid_pid = os.path.join(config['run_dir'], 'slapgrid-sr.pid')
+  if isPidFileProcessRunning(slapgrid_pid):
+    return False
   if not os.path.exists(config['software_root']):
     os.mkdir(config['software_root'])
   stopProxy(config)