foobarwidget / distributed-lock-google-cloud-storage-ruby Goto Github PK
View Code? Open in Web Editor NEWRuby implementation of a distributed lock based on Google Cloud Storage
License: MIT License
Ruby implementation of a distributed lock based on Google Cloud Storage
License: MIT License
I've been working on an alternative in Go, since I needed to support expiration, which gcslock
does not support.
Your article was very helpful, thanks.
There are few places where I've diverged from your implementation, which you may (or may not) find useful.
Feel free to close the issue at your discretion.
I use generations (rather than metagenerations) to "refresh" the lock. I do this for 2 reasons: because the XML API (which I use) does not allow me to update just the metadata, and because I optionally allow the user to attach data to the lock (and update/inspect it - I use this to report progress of the running operation).
However, there is an advantage to this. The generation of an object is less predictable than its metageneration. Given that the metageneration is so predictable (sequential), I'm actually not convinced it is safe to delete the lock based on just the metageneration.
I do not retry using PUT
(i.e. "create file"). Because of object immutability locking and unlocking a mutex is subject to the "once-per-second" quota. Contention from repeatedly trying to acquire the lock makes it harder to release it. So, after trying to optimistically acquire the lock, I immediately switch to using HEAD
to test the lock, so I don't contend with DELETE
, and only PUT
once the lock is gone or expired. HEAD
is also approximately 10 times cheaper than PUT
, so it really is better to loop on HEAD
.
I check for expiration based only on server time. I store a TTL in seconds in the metadata. I then use server date, last modification date of the lock and the TTL to determine if a lock is expired. Thus, local clock is one less thing to worry about.
A declarative, efficient, and flexible JavaScript library for building user interfaces.
๐ Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
The Web framework for perfectionists with deadlines.
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. ๐๐๐
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
We are working to build community through open source technology. NB: members must have two-factor auth.
Open source projects and samples from Microsoft.
Google โค๏ธ Open Source for everyone.
Alibaba Open Source for everyone
Data-Driven Documents codes.
China tencent open source team.