Distributed Locking with Postgres Advisory Locks
TL;DR
Postgres Advisory Locks are a great solution for arbitrary application locks, particularly in scenarios where you are already using Postgres and have a need to block concurrent mutations to a resource (that resource DOES NOT have to be data in Postgres).
Concurrency is hard
We ran into a problem . . .
Posted in: microservicesnodejspostgres
WebSequenceDiagrams.com TypeScript Client
https://gist.github.com/rclayton-the-terrible/493cd0811542ff9693ac02746517ba71
TL;DR - TypeScript Client Gist: https://gist.github.com/rclayton-the-terrible/493cd0811542ff9693ac02746517ba71
If you are not familiar with WebSequenceDiagrams, it's an excellent tool for creating sequence diagrams for planning software flows. If you are not familiar with sequence diagrams, a quick Google search will . . .
Posted in: architecturenodejstypescript
Node.js and Kafka in 2018
Yes, Node.js has support for all of the Kafka features you need.
If you want to use Node and Kafka together and are struggling to find straightforward answers to some basic questions, I hope this helps you out. We've been building out an event system at Peachjar using Node and Kafka and some of this knowledge is the fruit of our research.
What are the popular Kafka clients in Node?
- . . .
Use State Machines!
FSMs are not as complex as you think and they make your code better.
What is a State Machine?
Finite State Machines (FSM, or in the context of this post, simply "State Machines") are a methodology for modeling the behavior of an entity with an established lifecycle. The lifecycle is defined by an enumerated set of states known at the time of implementation (this is where the term . . .
Posted in: architecturenodejs
Scheduling Execution in Node.js
Differences between setTimeout, setImmediate, and process.nextTick.
A commonly misunderstood concept in Node.js is the difference between setTimeout, setImmediate, and process.nextTick. While all three functions are used to schedule the execution of a function, it is important to understand when Node.js will execute them.
Consider the following example:
setImmediate(() => console.log('Set . . .Posted in: nodejs
Reduce Test Boilerplate with Generic Test Functions
I wanted to quickly mention a trick I use to reduce the boilerplate code you'll often encounter when executing similar test cases. Instead of defining each test separately:
const { describe, it } = require('mocha');
const { expect } = require('chai');
const app = require('../../index.js');
. . .Posted in: nodejs
Enumerations in Node.js and Mongoose
Enumerations are essential to writing good software. Enumerations provide a clear understanding of the set of values that can be used for a property. This ensures we can constrain input to the set of values in the enumeration. Enumerations also signal to the reader the intended behavior of model instances (particularly if the enumerated field . . .
Posted in: nodejs
