By now it’s pretty clear that I’ve just had a bear of a time with locks and synchronization inside of multi-threaded environments with Go. Probably most gophers would simply tell me that I should share memory by communicating rather than to communication by sharing memory — and frankly I’m in that camp too. The issue is that: Mutexes can be more expressive than channels Channels are fairly heavyweight So to be honest, there are situations where a mutex is a better choice than a channel....

In Go, you can use sync.Mutex and sync.RWMutex objects to create thread-safe data structures in memory as discussed in [“Synchronizing Structs for Safe Concurrency in Go”]({% post_url 2017-02-21-synchronizing-structs %}). When using the sync.RWMutex in Go, there are two kinds of locks: read locks and write locks. The basic difference is that many read locks can be acquired at the same time, but only one write lock can be acquired at at time....

Building distributed systems in Go requires an RPC or message framework of some sort. In the systems I build I prefer to pass messages serialized with protocol buffers therefore a natural choice for me is grpc. The grpc library uses HTTP2 as a transport layer and provides a code generator based on the protocol buffer syntax making it very simple to use. For more detailed control, the ZMQ library is an excellent, low latency socket framework....

This post started out as a discussion of a struct in Go that could keep track of online statistics without keeping an array of values. It ended up being a lesson on over-engineering for concurrency. The spec of the routine was to build a data structure that could keep track of internal statistics of values over time in a space-saving fashion. The primary interface was a method, Update(sample float64), so that a new sample could be passed to the structure, updating internal parameters....

I’ve been looking for a way to quickly scan a file system and gather information about the files in directories contained within. I had been doing this with multiprocessing in Python, but figured Go could speed up my performance by a lot. What I discovered when I went down this path was the sync.ErrGroup, an extension of the sync.WaitGroup that helps manage the complexity of multiple go routines but also includes error handling!...

This is just a quick note on the performance of writing to a file on disk using Go, and reveals a question about a common programming paradigm that I am now suspicious of. I discovered that when I wrapped the open file object with a bufio.Writer that the performance of my writes to disk significantly increased. Ok, so this isn’t about simple file writing to disk, this is about a complex writer that does some seeking in the file writing to different positions and maintains the overall state of what’s on disk in memory, however the question remains:...

The event dispatcher pattern is extremely common in software design, particularly in languages like JavaScript that are primarily used for user interface work. The dispatcher is an object (usually a mixin to other objects) that can register callback functions for particular events. Then when a dispatch method is called with an event, the dispatcher calls each callback function in order of their registration and passes them a copy of the event....