One of the hard-won lessons of the last few weeks has been that inexplicable periodic latency jumps in network services should be met with an investigation into named.
John Mullerleile, Phil Kulak, and I gave a talk tonight, entitled “Scaling at Showyou.”
AWS::S3 is not threadsafe. Hell, it’s not even reusable; most methods go through a class constant. To use it in threaded code, it’s necessary to isolate S3 operations in memory. Fork to the rescue!
def s3(key, data, bucket, opts)
begin
fork_to do
AWS::S3::Base.establish_connection!(
:access_key_id => KEY,
:secret_access_key => SECRET
)
AWS::S3::S3Object.store key, data, bucket, opts
end
rescue Timeout::Error
raise SubprocessTimedOut
end
end
def fork_to(timeout = 4)
r, w, pid = nil, nil, nil
begin
# Open pipe
r, w = IO.pipe
# Start subprocess
pid = fork do
# Child
begin
r.close
val = begin
Timeout.timeout(timeout) do
# Run block
yield
end
rescue Exception => e
e
end
w.write Marshal.dump val
w.close
ensure
# YOU SHALL NOT PASS
# Skip at_exit handlers.
exit!
end
end
# Parent
w.close
Timeout.timeout(timeout) do
# Read value from pipe
begin
val = Marshal.load r.read
rescue ArgumentError => e
# Marshal data too short
# Subprocess likely exited without writing.
raise Timeout::Error
end
# Return or raise value from subprocess.
case val
when Exception
raise val
else
return val
end
end
ensure
if pid
Process.kill "TERM", pid rescue nil
Process.kill "KILL", pid rescue nil
Process.waitpid pid rescue nil
end
r.close rescue nil
w.close rescue nil
end
end
In distributed systems, one frequently needs a set of n nodes to come to a consensus on a particular coordinating or master node, referred to as the leader. Leader election protocols are used to establish this. Sure, you could do the Swedish or the Silverback, but there’s a whole world of consensus algorithms out there. For instance:
The Agent Smith
Hello, law enforcement. I suspect you’re reading this because, as a TSA supervisor told me recently, “… we are interested in you”.
Yes, I asked to fly selectee–to not provide ID–at Denver International recently. Yes, I’ve done this before. Yes, there was a lot of confusion between TSA employees on whether that was legal or not–eventually M. Gatling of the DIA police told me I was required to display ID. Yes, I opted out of AIT. Yes, it did take no fewer than eight TSA officers, airline representatives, and police about 45 minutes to determine I posed no threat. Yes, I was exceedingly polite, and most of us got along quite well. Yes, I was asked all kinds of questions I was under no obligation to answer (among them my address and phone number), and no, the TSA supervisor was not very pleased that I asked whether I was legally required to respond.
So Technology Review published a summary of an arxiv article arguing for mass quantization in black holes. Looks like an ultraviolet catastrophe argument, which is fascinating in itself. But first, I have to address this journalistic clusterfuck:
Of course, the question of this kind of black hole production at the LHC once again raises the thorny question of whether the safety assurances we’ve been given about these experiments are valid.
Bob and Sarah are a physicist and chemist, respectively. They should have known better than to send us mad libs for an RSVP card.
For only 650 per month, I could enjoy…
... an interest in: Group Habitation, Rocketry, Radio, Making Things, Creating Art, ReProgramming the World, Video Kaleidoscopes, Mad Science, Performing, Music or Entertaining, WareHousing, and the list goes on.
If you ever need to unzip data compressed with zlib without a header (e.g. produced by Erlang’s zlib:zip), it pays to be aware that
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits determines the window size. inflate() will then process raw deflate data, not looking for a zlib or gzip header, not generating a check value, and not looking for any check values for comparison at the end of the stream. (zlib.h)
Smear green blood
Your palms are sweaty
Scaly skin glistening
To last demands
The planet’s going under and
You’re floating overhead