abuckenheimer
Joined 12 years ago
Karma
212
Submissions
31
Member since
Oct 20
[ my public key: https://keybase.io/abuck; my proof: https://keybase.io/abuck/sigs/xYGIjUbi23GvI-UrSsod4bnZpsx0mL4amF_-T2ijbPM ]
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Comment · 1 year ago
excellent explanation, to add to this since I was curious about the composition, '%c' is an integer presentation type that tells python to format numbers as their corresponding unicode characters[1] so
'%c' * (length_of_string_to_format) % (number, number, ..., length_of_string_to_format_numbers_later)
is the expression being evaluated here after you collapse all of the 1s + math formatting each number in the tuple as a unicode char for each '%c' escape in the string corresponding to its place in the tuple.
[1] https://docs.python.org/3/library/string.html#format-specifi...
Comment · 1 year ago
This is really nice! The context switching that comes from using the [official k8s reference](https://kubernetes.io/docs/reference/kubernetes-api/workload...) is a real pain. If your writing a deployment and need to check one thing about the pod spec all of a sudden you jump to a new page and lost where you were. Ontop of that this keeps track of the indentation level the spec your looking at within the context of whatever parent path your writing it for.
Maybe one nitpick would be to keep colon between the key and the type so one can copy paste multiple lines of relevant spec to be filled in your editor easily.
Comment · 3 years ago
I've only skimmed the quickstart docs https://kargo.akuity.io/quickstart/ but this snippet immediately clicks for me as something that I'd want to try
cat <<EOF | kubectl apply -f -
apiVersion: kargo.akuity.io/v1alpha1
kind: Promotion
metadata:
name: prod-to-${FREIGHT_ID}
namespace: kargo-demo
spec:
stage: prod
freight: ${FREIGHT_ID}
EOF
Comment · 4 years ago
This is clever, otherwise you have to coordinate your cache setter and your async function call between potentially many concurrent calls. There are ways to do this coordination though, one implementation I've borrowed in practice in python is modes stampede decorator: https://github.com/ask/mode/blob/master/mode/utils/futures.p...
Comment · 4 years ago
> python3 -c 'while (1): print (1, end="")' | pv > /dev/null
python actually buffers its writes with print only flushing to stdout occasionally, you may want to try:
python3 -c 'while (1): print (1, end="", flush=True)' | pv > /dev/null
Comment · 6 years ago
Very cool, py-spy[1] has been an invaluable tool in my development process since jvns blogged[2] about it. The power of being able to visualize where your code is spending its time is so obvious and I'm glad people are building tools to make that easier.
As a quick compare and contrast between py-spy and pyinstrument it looks like py-spy has the advantage of being able to attach to an already running process which is super useful when your program is stuck and you don't know why. I haven't used pyinstrument yet but I do like the fact that it can do its flame graph in the console, sometimes I find saving down an svg file and opening up the browser a bit arduous. Excited to give it a try.
[1] https://github.com/benfred/py-spy
[2] https://jvns.ca/blog/2018/09/08/an-awesome-new-python-profil...
Comment · 6 years ago
It's interesting to compare palantir's risk factor on open source vs pivotals[1]. Palantir takes a defensive posture saying basically that their ability to not contribute to open source without running afoul their licenses is important:
Our platforms contain “open source” software, and any failure to comply with the terms of one or more of these open source licenses could negatively affect our business.
Where as pivotal says that being an active part of a vibrant open source community is crucial:
If open-source software programmers, many of whom we do not employ, or our own internal programmers do not continue to use, contribute to and enhance the open-source technologies that we rely on, the market appeal of our offering may be reduced, which could harm our reputation, diminish our brand and result in decreased revenue.
Like this makes sense, palantir is a closed source first kinda company and obviously a different value to its customers than pivotal. Kinda interesting to see that manifestation in the risk factors though.
[1] https://www.sec.gov/Archives/edgar/data/1574135/000104746918...
Comment · 6 years ago
Just remembered the puck building[1] has these on the sidewalks surrounding the Houston street side, if you go into the Eastern Mountain Sports store and down the stairs you can see them from below.
Comment · 7 years ago
Would highly suggest listening to the "How I built This" podcast[1] with the peleton founder John Foley, really great story with usual tech themes like doing things that don't scale and finding a niche but loyal customer base and expanding organically.
[1] https://play.google.com/music/m/Dmjr6m5i4h3j6gaysgjd47ryhci?...
Comment · 7 years ago
Yes HFT buys trade flow from robin hood because they make more money executing against it but that's not actually to the detriment of the people on the robin hood app. The main way HFT firms make money is by making a market, they offer to buy and sell stocks cheaper than anyone else and get paid by people crossing the spread and sometimes exchange fees. The reason robinhood trade flow is valuable to HFT firms Isn't because they are trading against "dumb" millennials but because they know millennials aren't likely to move the market playing around on their smartphone. HFT firms can collect a small rent sitting in between millenials trading with one another without the risk of being on the wrong side of a trade that materially moves the price of a stock.
Matt Levine does great write ups on this stuff, would highly recommend: https://www.bloomberg.com/opinion/articles/2018-10-16/carl-i...
Comment · 8 years ago
got it, thanks for the response!
Comment · 8 years ago
Right what I'm confused about is that first bit, my understanding from the RFC is that the implementation should have look something like
return pbkdf2.derive(password, email, PBKDF2_ROUNDS, STRETCHED_PASS_LENGTH_BYTES)
.then((quickStretchedPW) => {
result.quickStretchedPW = quickStretchedPW;
// stretch to twice the length necessary
return hkdf(quickStretchedPW, kw('generated'), HKDF_SALT, HKDF_LENGTH * 2)
.then((generated) => {
// split output into two cryptographically strong keys
result.unwrapBkey = generated.slice(0, HKDF_LENGTH);
result.authPW = generated.slice(HKDF_LENGTH);
}
);
}
)
hashed_password = hash(password, 'salt1')
hashed_auth_tok = hash(hashed_password, 'salt2')
hashed_unwrap_key = hash(hashed_password, 'salt3')
Comment · 8 years ago
I've never heard of HKDF before but it is really an elegant solution to this. My first guess on how to do this would have been something stupid like split the Authentication token in half and 0 pad it. But this would have significantly reduced the entropy available on both keys, reducing the search space on the authentication token and the encryption key making them much more brute force able. HKDF instead expands the key and essentially requires the server to be able to reverse HMAC-Hash to find the encryption key from the the authentication token.
What I'm confused about is that they seem to be using HKDF as a hash [1] and not as a key generation funciton. I think this is just as secure as what I was expecting but it seems more complicated and doesn't jive with the purpose of the RCA[2] as I read it.
[1] https://github.com/mozilla/fxa-js-client/blob/1d92f0ec458ace... (separate HKDF calls with the same IKM)
Comment · 8 years ago
I loved this article on the elegance of deflate http://www.codersnotes.com/notes/elegance-of-deflate/ finishes with this:
It's not one algorithm but two, that dance and weave together in harmony. You can pick dictionary matching, or entropy coding, and you can select between them on a per-byte basis with no overhead. That's what I find so clever about it - not that it can do one thing or the other, but that it can choose either, and yet represent them using the same language. No extra markers, nothing to say "oh, now we're switching to entropy mode", nothing to get in the way.