Category Archives: Snippet

Good concurrency changes the game

A long time before I seriously got into using distributed version control systems (DVCS) such as Bazaar and Git for developing software, it was already well known to me how the mechanics of these systems worked, and why people benefited … Continue reading

Posted in Architecture, Design, Go, Project, Snippet | 4 Comments

Death of goroutines under control

Certainly one of the reasons why many people are attracted to the Go language is its first-class concurrency aspects. Features like communication channels, lightweight processes (goroutines), and proper scheduling of these are not only native to the language but are … Continue reading

Posted in Architecture, Design, Erlang, Go, Project, Snippet, Test | 5 Comments

Efficient algorithm for expanding circular buffers

Circular buffers are based on an algorithm well known by any developer who’s got past the “Hello world!” days. They offer a number of key characteristics with wide applicability such as constant and efficient memory use, efficient FIFO semantics, etc. … Continue reading

Posted in Architecture, Article, C/C++, Erlang, Go, Haskell, Java, Lua, Perl, Python, Ruby, Snippet | 3 Comments

Vector clock support for Go

One more Go library oriented towards building distributed systems hot off the presses: govclock. This one offers full vector clock support for the Go language. Vector clocks allow recording and analyzing the inherent partial ordering of events in a distributed … Continue reading

Posted in Architecture, Cloud, Go, Project, Snippet | Leave a comment

Integrating Go with C: the ZooKeeper binding experience

ZooKeeper is a clever generic coordination server for distributed systems, and is one of the core softwares which facilitate the development of Ensemble (project for automagic IaaS deployments which we push at Canonical), so it was a natural choice to … Continue reading

Posted in Architecture, Article, C/C++, Go, Project, Snippet | 2 Comments

Removing seatbelts with the Go language for mmap support

Continuing the sequence of experiments I’ve been running with the Go language, I’ve just made available a tiny but useful new package: gommap. As one would imagine, this new package provides access to low-level memory mapping for files and devices, … Continue reading

Posted in Architecture, Go, Python, Snippet | 6 Comments

The forgotten art of error checking

I was just rambling randomly yesterday, in the usual microblogging platforms, about how result checking seems to be ignored or done badly. The precise wording was: It’s really amazing how little attention error handling receives in most software development. Even … Continue reading

Posted in Architecture, Go, Java, Lua, Perl, Python, Ruby, Snippet, Test | 10 Comments

Mocker 0.10 and trivial patch-mocking of existing objects

Mocker 0.10 is out, with a number of improvements! While we’re talking about Mocker, here is another interesting use case, exploring a pretty unique feature it offers. Suppose we want to test that a method hello() on an object will … Continue reading

Posted in Project, Python, Snippet, Test | 2 Comments

Partial stubbing of os.path.isfile() with Mocker

One neat feature which Mocker offers is the ability to very easily implement custom behavior on specific functions or methods. Take for instance the case where you want to pretend to some code that a given file exists, but you … Continue reading

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Python’s os.environ

As Chris Armstrong pointed out yesterday, os.environ.pop() is broken in Python versions at least up to 2.5. The method will simply remove the entry from the in-memory dictionary which holds a copy of the environment: >>> import os >>> os.system(“echo … Continue reading

Posted in Python, Snippet | 2 Comments