Strange Loop 2015: Notes & Reflections
Going to Strange Loop was a huge check off my conference bucket list (lanyard?). I’d always heard about this slightly-weird, highly academic collision between academia and industry, skewing toward programming languages you haven’t heard of (or, at the very least, you’ve never used in production). I anticipated sitting at the feet of gray-haired wizards and bright-eyed hipsters with Ph.Ds.
The conference did not disappoint. And it was not quite what I expected-I less sat at the feet of geniuses than I did talk with them, peer-to-peer, about topics of interest. All around me people were saying “Don’t be afraid to ask questions. Don’t feel stupid - nobody knows everything.” Speakers were tweeting about how much they were learning. It was comforting, because lots of topics I had come to see were those in which I had no. freakin. clue. about.
The following is culled from my notes from different sessions I attended. I will focus on brevity. I will keep it clear. Here we go:
Opening Keynote: “I see what you mean” - Peter Alvaro
- Instructions, behaviors & outcomes.
- It “feels good” to write in C (a hardcore 1000 liner)
- But a declarative program (e.g. SQL) works well, but is harder to come up with.
- The declarative world - as described in the work done in Datalog
- How can we take concepts from Datalog and apply to real-world resources like network actors (distributed systems)?
- It becomes easier to model these systems declaratively when we explicitly capture time.
- Enter Dedalus: extension to Datalog where time is a modeling construct.
- (Show off usage of
- Computation is redezvous - the only thing that you know is what YOU know at that point in time.
- Takeaway: Abstractions leak. Model them better (e.g. with time)
- Inventing languages is dope.
Have your Causality and your Wall Clocks Too (Jon Moore)
- Take concept of Lamport clocks and extend them with hybrid clocks.
- And extend them one further with: Distributed Monotonic Clocks
- These DMCs use population protocol (flocking) to each actor in the system communicate with another, updating their source of truth to eventually agree on a media time w/in the group
- DMC components:
- Have a reset button by adding epoch bit
- Use flocking (via population protocol) to avoid resets
- Accomodates for some clockless nodes
- Explicitly reflects causality
Building Isomorphic Web Apps with React - Elyse Gordon
- Vevo needed better SEO for SPAs. Old soln was to snapshot page and upload to S3.
- Beneficial for SEO crawlers
- React in frontend. Node in backend.
- Vevo-developed pellet project as Flux-like framework to organize files.
- Webpack aliases/shims
- Server hands off to browser, bootstraps React in client.
- Alternatives: Relay, Ember
Designing for the Worst Case: Peter Bailis (@pbailis)
- Designing for worst case often penalizes average case
- But what if designing for the worst case actually helps avg case?
- Examples from dstbd systems:
- Worst case of disconnected data centers, packet loss/link loss. Fix by introducing coordination-free protocols. Boom, you’ve now made your network more scalable, performant, resistent to downtime.
- Worst case: hard to coordinate a distributed transaction between services. What do you do? You implement something like buffered writes out of process.
- CRDT, RAMP, HAT, bloom
- Suddenly, you have fault tolerance
- Tail latency problem in microservices: the more microservices you query, the higher the probability of hitting a slow server response.
- Your service’s corner case is your user’s average case
- HCI: accessibility guidelines in W3C lift standards for all. Make webpages easier to navigate. Side effect of better page performance, higher conversion.
- Netflix designing CC subtitles also benefits other users.
- Curb cuts in the real world to help ADA/mobility-assisted folks also benefit normal folks too
- Best has pitfalls too: your notion of best may be hard to hit, or risky. You may want to optimize for “stable” solution. (Robust optimization)
- When to design for worst case?
- common corner cases
- environmental conditions vary
- “normal” isn’t normal
- worst forces a conversation
- how do we plan for failures?
- what is our scale-out strategy?
- how do we audit failures? data breaches?
Ideology by Gary Bernardt
- Rumsfeld: known knowns, known unknowns, and unknown unknowns.
- Ideology is the thing you know you do not know you know
- Conflict between typed vs dynamic programmers:
- Typed: “I don’t need tests, I have types”
- Dynamic: “I write tests, so I don’t need types”
- In reality, they are solving different places in the problem domain, but they have different beliefs about the world that are hidden in the shadows:
- Typed: “Correctness comes solely from types”
- Dynamic: “Correctness comes solely from example”
- “I need nulls” -> You believe nulls are the only way to represent absence
- “Immutable data structures are slow” -> You believe all immutable types are slow
- “GC is impractical” -> you believe GC algorithms won’t get faster.
- Read CSE 341 Type systems, Dan Grossman
Building Scalable, Stateful Services: Caitlin McCaffrey
Sticky connection: always talk to the same machine
Building sticky connections:
- persistent connections (load balancing cannot rebalance server)
- implement backpressure (d/c connection)
dynamic cluster membership
- gossip protocols -> availability
- consensus systems -> consistency (everybody needs to have the same worldview.
- write anywhere, read from all
consistent hashing: on session ID
hash space -> node dynamoDB, Manhattan
con: can have hotspots, could have uneven distribution of resources cannot move work.
distributed hash table
statefully store hash
- distributed in-memory DB
- Node.js swim gossip protocol, consistent hashing
Orleans (MS Research)
- actor model
- consistent hash
- distributed hashtable
Idalin “Abby” Bobé: From Protesting to Programming: Becoming a Tech Activist
- Tech to resist exploitation
- Technologists as activists
- Idalin Bobé -> Changed name to “Abby” to get a job.
- Pastor Jenkins - magnifying glass vs paper
- Philadelphia Partnership Program:
- 1st to college
- work <> school
- Difficult to balance.
- Mills MBA, CS
- Joined Black Girls Code
- Apply technology in the right way
- Ferguson happened
- Thoughtworkers joined on the ground
- Hands Up United: www.handsupunited.org
- “Do not be led by digital metrics” - even though the activists had digital tooling, the tools were being used against activists. Phone calls, chats monitored. Movement tracked.
- New group starting up in St. Louis called “Ray Clark, Sr.” - named after a black man who played a strong role in the founding of Silicon Valley.
- 21st century technologists need 21st century skillsets.
- Dream Defenders
- “it is our duty to fight for our freedom/it is our duty to win/we must love and support one another/we have nothing to lose but our chains”