9 June 2010

Why the name change?

/etc/dhcp3
/etc/dhcp
(notifications-notify
    :title "You've got mail!"
    :body "There's 34 mails unread"
    :app-icon "~/.emacs.d/icons/mail.png"
    :urgency 'low)

2010-06-09  Julien Danjou  <julien@danjou.info>
        * net/notifications.el: New file.

0.8.1   2010-06-08
    o   This release adds Rcpp modules. An Rcpp module is a collection of
        internal (C++) functions and classes that are exposed to R. This
        functionality has been inspired by Boost.Python.
        
        Modules are created internally using the RCPP_MODULE macro and
        retrieved in the R side with the Module function. This is a preview 
        release of the module functionality, which will keep improving until
        the Rcpp 0.9.0 release. 
        The new vignette "Rcpp-modules" documents the current feature set of
        Rcpp modules.
        
    o   The new vignette "Rcpp-package" details the steps involved in making a
        package that uses Rcpp.
    o   The new vignette "Rcpp-FAQ" collects a number of frequently asked
        questions and answers about Rcpp.
    o   The new vignette "Rcpp-extending" documents how to extend Rcpp
        with user defined types or types from third party libraries. Based on
        our experience with RcppArmadillo
        
    o   Rcpp.package.skeleton has been improved to generate a package using 
        an Rcpp module, controlled by the "module" argument
    o   Evaluating a call inside an environment did not work properly
        
    o   cppfunction has been withdrawn since the introduction of the more
        flexible cxxfunction in the inline package (0.3.5). Rcpp no longer
        depends on inline since many uses of Rcpp do not require inline at
        all. We still use inline for unit tests but this is now handled
        locally in the unit tests loader runTests.R. 
        Users of the now-withdrawn function cppfunction can redefine it as:
        
           cppfunction <- function(...) cxxfunction( ..., plugin = "Rcpp" )
    o   Support for std::complex was incomplete and has been enhanced.
    o   The methods XPtr<t>::getTag and XPtr<t>::getProtected are deprecated, 
        and will be removed in Rcpp 0.8.2. The methods tag() and prot() should
        be used instead. tag() and prot() support both LHS and RHS use. 
    o   END_RCPP now returns the R Nil values; new macro VOID_END_RCPP
        replicates prior behabiour
        

import time
class Lock(object):
    def __init__(self, key, expires=60, timeout=10):
        """
        Distributed locking using Redis SETNX and GETSET.
        Usage::
            with Lock('my_lock'):
                print "Critical section"
        :param  expires     We consider any existing lock older than
                             expires  seconds to be invalid in order to
                            detect crashed clients. This value must be higher
                            than it takes the critical section to execute.
        :param  timeout     If another client has already obtained the lock,
                            sleep for a maximum of  timeout  seconds before
                            giving up. A value of 0 means we never wait.
        """
        self.key = key
        self.timeout = timeout
        self.expires = expires
    def __enter__(self):
        timeout = self.timeout
        while timeout >= 0:
            expires = time.time() + self.expires + 1
            if redis.setnx(self.key, expires):
                # We gained the lock; enter critical section
                return
            current_value = redis.get(self.key)
            # We found an expired lock and nobody raced us to replacing it
            if current_value and float(current_value) < time.time() and \
                redis.getset(self.key, expires) == current_value:
                    return
            timeout -= 1
            time.sleep(1)
        raise LockTimeout("Timeout whilst waiting for lock")
    def __exit__(self, exc_type, exc_value, traceback):
        redis.delete(self.key)
class LockTimeout(BaseException):
    pass

def cache_without_dogpiling(key, cb, cache_expiry=None, *args, **kwargs):
    val = cache.get(key)
    if val is not None:
        return val
    # Cache miss; gain the lock to prevent multiple clients calling cb()
    with Lock(key, *args, **kwargs):
        # Check cache again - another client may have set the cache
        val = cache.get(key)
        if val is None:
            val = cb()
            cache.set(key, val, cache_expiry)
        return val
def slow():
    print "Inside slow()"
    return 1 + 1 # Python is slow
>>> cache_without_dogpiling('my_key', slow, 60 * 10)
Inside slow()
2
>>> cache_without_dogpiling('my_key', slow, 60 * 10)
2

import contextlib
@contextlib.contextmanager
def Lock(*args, **kwargs):
    yield

	Development	Operations
is responsible for	creating products	offering services
is measured on	delivery of new features	high reliability
optimizes by	increasing velocity	controlling change
and so is perceived as	reckless and irresponsible	obstructing progress

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9 June 2010

Russell Coker: Mailing List Meta-Discussions

Ross Burton: Gypsy 0.8 Released

David Welton: Some difficult decisions?

Gerfried Fuchs: Battle for Wesnoth 1.8

Russell Coker: Does Every Serious Mailing List need a Non-Serious Counterpart?

Andrew Pollock: [debian] ISC DHCP 4.1 package progress report

Julien Danjou: Desktop notification support for Emacs

8 June 2010

Dirk Eddelbuettel: Rcpp 0.8.1

Adrian von Bidder: Blue Velvet

Mike Hommey: Playing with icegrind

Uwe Hermann: flashrom 0.9.2 released -- Open-Source, crossplatform BIOS / EEPROM / flash chip programmer

Matt Zimmerman: DevOps and Cloud

Russell Coker: Is the PC Dying?

7 June 2010

John Goerzen: Boys

Martín Ferrari: Python WTF

Steve McIntyre: Also sad about the Poulsbong^H^H

Chris Lamb: Distributing locking with Python and Redis

Sjoerd Simons: Is that a tea cosy on your head?

Riku Voipio: WebGL on N900

Julien Danjou: Announcing erc-track-score