Exercises in learning the Go programming language

2pc/node.go - Presume-abort two-phase commit

This is a UDP-based proof-of-concept implementation of the simple and popular two-phase commit protocol. It uses three processes as illustrated in the example usage at the top of the source.

android-apps/recommendations.go - Sam Rowe's Android app list

When I tweeted about my new Android phone, my friend Sam Rowe sent me a list of recommended apps. His email said, "Here's the fun version. Let me know if you need the unfun version."

More details are in the program.

bakery.go - Go implementation of 1974 Lamport bakery algorithm

Leslie Lamport, author of the LaTeX macropackage for Don Knuth's TeX typesetting engine, is also famous for his often-cited papers on distributed computing.

In his collection of papers, he has reflections written about each. His estimation of the bakery algorithm as a distributable mutual exclusion mechanism is that it has been underestimated for years.

One nice property is that it resists the failure of a participant (as long as the participant doesn't use the exclusive resource while "failed"). Another is that writes to any single location are performed exclusively by a single participant, but a single location is read by multiple participants.

http://research.microsoft.com/en-us/um/people/lamport/pubs/pubs.html#bakery

The paper has a really simple listing that translates easily into code. My program's "proc" function mirrors the paper's pseudocode.

http://research.microsoft.com/en-us/um/people/lamport/pubs/bakery.pdf

This Go program has the different participants on the same machine, and I learned that if I set the number of Go processes to the number of CPUs, the busy waiting in the algorithm works great. If Go has to multiplex the goroutines onto shared O.S. threads, then they're acting as coroutines, so the runtime.Gosched() call is needed in the busy wait for the coroutines to yield the CPU.

bakery-v.go - Verbose Go implementation of 1974 Lamport bakery algorithm

bakery-dist.go - Distributed Go implementation of Lamport's bakery

This distributed implementation shows how to use Go's HTTP RPC features. In a production app where more performance was desired, connections could be reused.

selfwrite.go - Go program that writes its own source to stdout

linesrv.go - Simple web server demo

closure.go - Linked list iterator callback illustrates closure

observer.go - judge for correctness of bakery implementation

l77rw1.go - concurrent multiple readers / single writer

based on Leslie Lamport's 1977 paper, "Concurrent Reading and Writing"

clhlock.go - Travis Craig and Magnussen, Landin, Hagersten lock demo

paxos/bpaxos.go - basic Paxos implementation

paxos/upaxos.go - IP-based unreliable broadcast Paxos demo

paxos/iptest-send.go - Send to IP broadcast

web/shareform/ - Demo of a multi-user web form edited concurrently