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An oral history of Bank Python

calpaterson.com

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Re: An oral history of Bank Python

#21

Post by seanhunter »

I was the person who first deployed Python at Goldman Sachs. At the time it was an "unapproved technology" but the partner in charge of my division called me and said (This is literally word for word because partners didn't call me every day so I remember)

    Err....hi Sean, It's Armen.  Uhh.... So I heard you like python.... well if someone was to uhh.... install python on the train... they probably wouldn't be fired.  Ok bye.
"Installing python on the train" meant pushing it out to all the computers globally in the securities division that did risk and pricing. Within 30mins every computer in goldman sachs's securities division had python and I was the guy responsible for keeping the canonical python distribution up to date with the right set of modules etc on Linux, Solaris and Windows.

Because it was unapproved technology I had a stream of people from technology coming to my desk to say I shouldn't have done it. I redirected them to Armen (who was a very important dude that everyone was frightened of).

The core engineers from GS went on to build the Athena system at JP and the Quartz platform at BAML.

//Edit for grammar

Re: An oral history of Bank Python

#23

Post by seanhunter »

cstross wrote: post #11

This immediately sprang out at me: > Investment banks have a one-way approach to open source software: (some of) it can come in, but none of it can go out. I wonder how well this plays with the various open source software licenses?

That's actually an unfortunate side-effect of banks having weird requirements. When I was at GS we had this enormous source repo built on CVS. So we made improvements to CVS to try to make this more manageable . For example because branching in CVS absolutely sucks we had to use tags (rather than branches) to identify releases. This meant you end up with lots of tags and when you look at them it's really hard to find (visually) whether code has a particular tag. So we patched CVS to sort the tags alphabetically. We tried to upstream this but the CVS devs didn't want to know. So we had to maintain it.

Likewise a bunch of fixes to the timezone handling code that iirc glibc simply wouldn't upstream so we had to maintain even though they were bugfixes.

We did used to upstream everything we could and I think the situation is improving.

Re: An oral history of Bank Python

#24

Post by rich_sasha »

lmm wrote: post #19

I'm seeing a lot of people speculating about which bank this might be; I think the point is that it's all of them. I could loosely describe a previous job as implementing Morgan Stanley's Walpole and integrating more source code management into Minerva (even though that system wasn't actually Python-based). Having a global view on everything is large banks' value-add, it's why they haven't been outcompeted by their m…

I think it’s mostly true. The complaint with this kind of “industrial global Python code base”, be it at banks or elsewhere, is that often they are hastily cobbled together and depend on extreme user care to not flop over all the time.

I guess banks are the archetypal places that care only about feature creation and not about maintenance or technical debt. When something does break in the end, someone senior just shouts at the poor devs until it works again - usually fixed with a hasty patch again.

Similarly, documentation? Access control? Sanity? These seem to be left behind.

Re: An oral history of Bank Python

#25

Post by lanevorockz »

seanhunter wrote: post #21

I was the person who first deployed Python at Goldman Sachs. At the time it was an "unapproved technology" but the partner in charge of my division called me and said (This is literally word for word because partners didn't call me every day so I remember) Err....hi Sean, It's Armen. Uhh.... So I heard you like python.... well if someone was to uhh.... install python on the train... they probably wouldn't be fired. O…

Python Quants for the win ! I was lazy enough to stay with R but it was nice of Wes of building pandas, made adoption super easy.

Re: An oral history of Bank Python

#26

Post by tikkabhuna »

seanhunter wrote: post #21

I was the person who first deployed Python at Goldman Sachs. At the time it was an "unapproved technology" but the partner in charge of my division called me and said (This is literally word for word because partners didn't call me every day so I remember) Err....hi Sean, It's Armen. Uhh.... So I heard you like python.... well if someone was to uhh.... install python on the train... they probably wouldn't be fired. O…

I joined the BAML grad scheme 10 or so years ago. We had a presentation from one of the Quartz guys and someone asked how they’d manage upgrading the version of Python. They were using something like 2.6.5. The whole move to 3.x was a thing. The Quartz guy just flat out said they wouldn’t upgrade.

Seemed crazy to a new grad back then, but now I wouldn’t want to consider it either.

Thanks for your contribution! It was amazing that even in my role where I didn’t use Quartz, I could see and search all the code. Felt quite novel back then.

Re: An oral history of Bank Python

#27

Post by blitzar »

jeffrallen wrote: post #17
sfgweilr4f wrote: post #7

Earlier quoted context omitted.

Or they could use instead use CSVs. What could possibly go wrong?

Everything is fine, as long as no Americans come and write 1,000 where obviously they should have written 1000 or 1'000. /s

Or some american writes the date somewhere.

edit: /s we love you american colleagues,

Re: An oral history of Bank Python

#29

Post by lmm »

rich_sasha wrote: post #24
lmm wrote: post #19

I'm seeing a lot of people speculating about which bank this might be; I think the point is that it's all of them. I could loosely describe a previous job as implementing Morgan Stanley's Walpole and integrating more source code management into Minerva (even though that system wasn't actually Python-based). Having a global view on everything is large banks' value-add, it's why they haven't been outcompeted by their m…

I think it’s mostly true. The complaint with this kind of “industrial global Python code base”, be it at banks or elsewhere, is that often they are hastily cobbled together and depend on extreme user care to not flop over all the time. I guess banks are the archetypal places that care only about feature creation and not about maintenance or technical debt. When something does break in the end, someone senior just sho…

Hmm, I found the opposite - the fact that there was this global framework that managed all the data and code meant that access control was actually pretty good, better than most tech companies I've worked for. You had a single source of truth for what your access rights were, there was integrated Kerberos any time you needed to access a system outside Minerva. And having all the code in a managed place meant good deprecation cycles - not instant deprecation like the Google monorepo, but tracking and policy for which old versions of libraries were in use and how much that was tolerated. Documentation was at least attempted, and while platform stability/enhancement work did have to be coupled to business initiatives to a certain extent (e.g. "we're doing this performance work to enable us to run risk estimation more often to meet MIFID requirements at low cost") there was leadership that put a value on maintaining high quality code and this paid dividends.

Re: An oral history of Bank Python

#30

Post by lozenge »

tikkabhuna wrote: post #26
seanhunter wrote: post #21

I was the person who first deployed Python at Goldman Sachs. At the time it was an "unapproved technology" but the partner in charge of my division called me and said (This is literally word for word because partners didn't call me every day so I remember) Err....hi Sean, It's Armen. Uhh.... So I heard you like python.... well if someone was to uhh.... install python on the train... they probably wouldn't be fired. O…

I joined the BAML grad scheme 10 or so years ago. We had a presentation from one of the Quartz guys and someone asked how they’d manage upgrading the version of Python. They were using something like 2.6.5. The whole move to 3.x was a thing. The Quartz guy just flat out said they wouldn’t upgrade. Seemed crazy to a new grad back then, but now I wouldn’t want to consider it either. Thanks for your contribution! It was…

BAML(Quartz) and JPM(Athena) both had Python 3 migrations well underway as of PyCon UK 2019.

It took me more than half way down the article to identify I have not worked at the same bank as the author...

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