The Advisory Boar
My friend Nicolai Langfeldt (author of the
DNS HOWTO) works at a
large ISP, where he recently needed to ping somewhere between 10,000 and
100,000 hosts every ten seconds and feed the up/down data to Nagios. He
had started hacking on fping to do this, but I thought it could be done
better by a smaller program written specifically for this purpose.
I wrote most of
on a flight home. It takes a list of IP addresses on the command line,
writes ICMP echo requests for each address to a raw socket every ten
seconds, and creates another process to print the response time (or
"unreachable") for each response. It does nothing else, and does not
need to allocate any memory after startup.
Nicolai's preliminary tests show that it can send out the 10k pings in
under 100ms, which far exceeds the performance I was hoping for (though
his networking colleagues may yet frown upon sending that many pings so
fast). With that kind of performance, monitoring 100k hosts isn't out of
the question, even if the sender has to be slowed down a bit.
The code is on github in case anyone else finds it useful. Feedback is
While looking for something that could be adapted for this use, I found
the source code of the original ping.c
on the ISOC web site. I decided against modifying it because of several
misleading comments, type abuse (e.g. allocating a struct sockaddr and
casting its address to struct sockaddr_in *), and other K&R/BSD
oddities. But it's good code overall, and it was instructive to look
announced snippets on rant.gulbrandsen last month, I thought I'd
write a quick introduction to it here as well.
Snippets is a Jabber bot that periodically asks its subscribers what
they're doing, and provides access to the answers through a simple web
interface. It is meant primarily to help teams of developers to
communicate with each other.
Snippets is a Perl program that depends on a few CPAN modules, and needs
access to a Postgres database. You can get the source from the
github page, and
installation instructions are given in the
Feedback and feature requests are welcome. Please send them to
Hassath wanted to download a couple of gigabytes worth of mail from her
GMail account for offline storage, but was frustrated by the IMAP server
closing the connection during large transfers, which made Thunderbird go
into a sulk, and forced her to restart the download by hand every time.
Using POP was not an option, since it had no way to preserve the labels
she had assigned to the messages (which show up as mailboxes via IMAP).
I tried some other programs, but they didn't work the way I wanted. Some
of them provided little or no progress information. Some would fetch all
of the messages into memory before writing anything to disk. Some would
fetch messages one by one, with separate command-response cycles. Most
importantly, none of them coped well with the frequent disconnections.
Having exhausted my patience, and being in need of a weekend hack, I set
out to write a program to download the mail. I tried the IMAP modules on
CPAN, but found them lacking in one way or another. IMAP::Client parses
IMAP responses in a fundamentally broken way (scanning literal data for
things which look like OK responses). Net::IMAP::Client doesn't provide
debugging information or allow MSN fetches. Net::IMAP doesn't know about
IMAP+SSL. Most importantly, none of the modules would allow me to stream
messages to disk sensibly. So I wrote one from scratch.
I started using Blosxom a few weeks
ago. I liked the basic idea (that each post is one file) very much, but
I found the code hard to read and poorly documented. Plugins varied
widely in quality, and I had to jump through hoops to implement some of
the things I wanted. By the time I got everything working the way I
liked it, I ended up with a complete rewrite.
The code is well-documented, supports tagging and pagination, generates
an RSS feed, works nicely with Git, and lets me publish URLs like
(Disadvantages: it isn't quite plugin-compatible with Blosxom, and it
doesn't support static generation.)
I'm sure I could have used a more modern, featureful program to achieve
the same effect, but I'm glad I didn't have to. I was happier to spend
a couple of hours writing something worse than a few days trying to fit
something better, like Wordpress,
into my head.
I wrote this code for my own use with no intention of releasing it, but
a few people have expressed an interest in using it, so here it is.
No longer maintained
Update (November 2013): Loathsxome never had more than a handful
of users, and only two who regularly contributed code
(Arnt Gulbrandsen and
myself). Arnt wrote
plusxome, and I wrote
something else using Mojolicious without even pretending to maintain
Loathsxome is still here. It works as well as it ever did, and none of
what's written below is untrue, but nobody uses it any more.
Inspector34 is a transparent web proxy that records requests and
responses for later playback and comparison. It is meant to help
with regression testing.
It consists of three programs:
i34-record is the proxy
server, which keeps a journal of HTTP requests and responses; and
i34-replay recreates the original requests from this
i34-diff compares responses from the original
and replayed sessions.
Inspector34 is written in Perl, and is distributed under a BSD-style
open source license. Feedback is welcome.