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Appendices A. Concept of volumeMeter All scenarios are using a mysterious variable volumeMeter. It allows me to emulate lag of volume measurement in controlled fashion Note: You don't need to study the contents of volumeMeter as long as you assume that it is a function that provides current volume and is designed to …

Asynchronous approach (ctd) Channels (ctd) Solution with channels and a Goroutine This solution uses Goroutine to measure volume upon request, and a request and response channels to communicate between Goroutine and main loop. In practise, the volume measurement is continuous, because request for volume is sent as soon …

Asynchronous approach (ctd) Channels (ctd) Channel and Goroutine None of the previous examples demonstrated channels in the environment where they make most sense - concurrent one. My intention was to keep the examples as simple as possible and, at the same time, demonstrate the use of channels in synchronous way. What …

Asynchronous approach (ctd) Channels (ctd) Select statement If you want to embrace Go's channels, but are feeling constrained by all the blocking operations on them, select will make your day. It is part of Go's syntax and - in its simplicity - it's stunning how powerful it is. Link to documentation. Non-blocking …

Asynchronous approach (ctd) Channels Channels are extremely important in Go. They require shift of concurrent system design paradigm but they also ease you into it. I'm not going to scrimp on space to introduce them. What are channels in Go? Channels are the pipes that connect concurrent goroutines. You can send …

Asynchronous approach (ctd) Mutex Term stands for mutual exclusion. In programming it is a property limiting resource access to one thread (or even one consumer - due to lack of reentrancy, later about that) at a time. Sounds familiar? In previous section the atomic functions were helping us achieve just that in …

Asynchronous approach (ctd) Atomic Go provides you with sync/atomic package to help you with sharing state correctly. The tools within that package will help us provide implementation of metronome's engine with much more reliable performance. Let's start with generic definition of atomicity atomicity /ˌatəˈmɪsɪti/ …

Asynchronous approach (ctd) Sharing access to mutable state Our solutions utilising Goroutines purposefully didn't share much state between Goroutines. I didn't want to pile it on you straight from start. A little exception was a solution with WaitGroup which allowed us to synchronise the completion of all Goroutines …

Asynchronous approach (ctd) WaitGroup Most asynchronous activities need a mechanism to signal completion with the option to deliver its outcome. We do this so that we can gather results of these Goroutines or just to to proceed once their effect sets, including graceful application termination scenario. Note: I am …