Merge pull request #2 from sayanarijit/dev

v2

.travis.yml

@@ -5,6 +5,10 @@ python:
 install:
     - python setup.py install
 script:
-    - python setup.py test
     - python ./pidlock.py --version
     - python ./pidlock.py --name test --command pwd --lockdir ~/.pidlock --verbose
+    - python ./pidlock.py --name test --command pwd --lockdir ~/.pidlock --verbose -w 1 -m .05
+    - python ./pidlock.py -n test -c pwd -l ~/.pidlock -v -w 1 -m .05
+    - python ./pidlock.py -n test -c "sleep 10" -v &
+    - python ./pidlock.py -n test -c "pwd" -v -w 3; [ $? -eq 1 ] || false
+    - python ./pidlock.py -n test -c "pwd" -v -w 7 -m .5

README.md

@@ -47,16 +47,19 @@ pidlock --name sleepy_script --command 'sleep 10'
 
 ### Customization:
 
-* You can pass PID file location and verbosity as arguments
+* You can pass PID file location, verbosity, time limit and minimum interval as arguments
 
 ```
 # Python Usage
 locker = PIDLock(lockdir='~/.pidlock', verbose=True)
+
+with locker.lock('sleepy_script', wait=10, mininterval=1):
+    time.sleep(10)
 ```
 ```
 # Commandline usage
-pidlock -n sleepy_script -c 'sleep 10' -l ~/.pidlock -v
+pidlock -n sleepy_script -c 'sleep 10' -l ~/.pidlock -v -w 10 -m 1
 
 # Same as
-pidlock --name sleepy_script --command 'sleep 10' --lockdir ~/.pidlock --verbose
+pidlock --name sleepy_script --command 'sleep 10' --lockdir ~/.pidlock --verbose --wait 10 --mininterval 1
 ```

pidlock.py

@@ -1,20 +1,21 @@
 # -*-coding: utf-8 -*-
 '''
-Author:         Arijit Basu
-Email:          sayanarijit@gmail.com
-Documentation:  https://github.com/sayanarijit/pidlock
+Author:         Arijit Basu <sayanarijit@gmail.com>
+Documentation:  https://github.com/sayanarijit/pidlock#pidlock
 '''
 
 from __future__ import print_function
 import os
 import sys
+import time
 import psutil
 from os import path
 from codecs import open
+from subprocess import Popen
 from contextlib import contextmanager
 
 
-VERSION = 'v1.1.0'
+VERSION = 'v2.0.0'
 
 
 class PIDLockedException(Exception):
@@ -23,25 +24,33 @@ def __init__(self, name, pid):
 
 
 class PIDLock:
-    """
-    PARAMETERS:
-        lockdir: str: (default: ~/.pidlock) Where to create/store PID lock files
-        verbose: bool: (default: True) Verbosity
-    RAISES:
-        PIDLockedException
-    EXAMPLE:
-        import time
-        from pidlock import PIDLock
-        locker = PIDLock()
-        with locker.lock('sleepy_script'):
-            time.sleep(10)
+    """PIDLock class
+
+    Args:
+        lockdir: (str) Where to create/store PID lock files. Default is '~/.pidlock'
+        verbose: (bool) Prints verbose outputs. Default is False
+    Example:
+        >>> from pidlock import PIDLock
+        >>> locker = PIDLock(lockdir='~/.pidlock', verbose=True)
     """
     def __init__(self, lockdir='~/.pidlock', verbose=True):
         self.lockdir = path.expanduser(lockdir)
         self.verbose = verbose
 
     @contextmanager
-    def lock(self, name):
+    def lock(self, name, wait=0, mininterval=1):
+        """Locks process till codes inside "with" block is executed
+
+        Args:
+            name: (str) Name of the file to be used as lock
+            wait: (float) How long (sec.) should it wait for lock to be released. Default is 0
+            mininterval: (float) Minimum interval (sec.) to balance between performance and resource usage. Default is 1
+        Raises:
+            PIDLockedException: PID file is locked by another process
+        Example:
+            >>> with locker.lock(name='sleepy_script', wait=0, mininterval=1):
+            >>>     time.sleep(10)
+        """
         if not path.isdir(self.lockdir): os.mkdir(self.lockdir)
 
         pidfile = path.join(self.lockdir, name + ".pid")
@@ -52,17 +61,37 @@ def lock(self, name):
             f = open(pidfile, encoding='utf-8')
             xpid = int(f.read())
             f.close()
-            # If pid exists, quit
+            # If pid exists
             pids = psutil.pids()
             pids.remove(pid)
             if xpid in pids:
-                raise PIDLockedException(name, xpid)
+                if self.verbose:
+                    print('PID file is locked with PID:', xpid)
+                    print('Waiting for lock to be released...')
+
+                # Wait till it's released or time limit is over
+                now = time.time()
+                while time.time() - now < wait and xpid in pids:
+                    if self.verbose:
+                        print('Still waiting...')
+                    time.sleep(mininterval)
+                    pids = psutil.pids()
+                    pids.remove(pid)
+
+                if xpid in pids:
+                    # Time limit is over, raise exception
+                    raise PIDLockedException(name, xpid)
+
             # Else remove lock
-            os.remove(pidfile)
+            else:
+                if self.verbose:
+                    print('Removing old pidfile...')
+                os.remove(pidfile)
 
         # Else create lock
         if self.verbose:
             print('Locking "{}" with PID: {}'.format(name, pid))
+
         f = open(pidfile, "w", encoding='utf-8')
         f.write(str(pid))
         f.close()
@@ -72,18 +101,20 @@ def lock(self, name):
             yield
         finally:
             # Finally close the PID file
+            os.remove(pidfile)
             if self.verbose:
                 print('Released lock...')
-            os.remove(pidfile)
 
 
 def pidlock_cli():
-    """
-    CLI interface for PID based locking
-    USAGE:
+    """CLI interface for PID based locking
+
+    Usage:
         pidlock [-h] -n NAME -c COMMAND [--version]
-    EXAMPLE:
-        pidlock -n sleepy_script -c 'sleep 10'
+    Returns:
+        Returns the returncode returned by the executed command
+    Example:
+        $ pidlock -n sleepy_script -c 'sleep 10'
     """
     import argparse
 
@@ -99,17 +130,21 @@ def pidlock_cli():
         help='directory to keep lock files. (default: ~/.pidlock)', default='~/.pidlock')
     parser.add_argument('-v', '--verbose',
         action='store_true', help='use this flag to make it verbose. (default: False)', default=False)
+    parser.add_argument('-w', '--wait',
+        type=float, help='how long (sec.) to wait for PID file to be released. (default: 0)', default=0)
+    parser.add_argument('-m', '--mininterval',
+        type=float, help='minimum interval (sec.) to balance between performance and resource usage. (default: 1)', default=1)
     parser.add_argument('-V', '--version',
         action='version', version='pidlock '+VERSION)
 
     parsed = parser.parse_args()
 
-    locker = PIDLock(parsed.lockdir, parsed.verbose)
+    locker = PIDLock(lockdir=parsed.lockdir, verbose=parsed.verbose)
     try:
-        with locker.lock(parsed.name):
+        with locker.lock(name=parsed.name, wait=parsed.wait, mininterval=parsed.mininterval):
             if parsed.verbose:
                 print("Running command:", parsed.command)
-            quit(os.system(parsed.command))
+            quit(Popen(parsed.command, shell=True).wait())
     except PIDLockedException as e:
         print('pidlock:', e, file=sys.stderr)
         quit(1)

requirements.txt

@@ -1,2 +1 @@
-argparse==1.4.0
 psutil==5.4.3

setup.py

@@ -2,7 +2,7 @@
 from codecs import open
 from os import path
 
-VERSION = 'v1.1.5'
+VERSION = 'v2.0.0'
 
 here = path.abspath(path.dirname(__file__))