{"id":23,"date":"2021-10-22T04:05:44","date_gmt":"2021-10-22T04:05:44","guid":{"rendered":"https:\/\/blogs.oregonstate.edu\/sandfield\/?p=23"},"modified":"2021-10-22T04:05:44","modified_gmt":"2021-10-22T04:05:44","slug":"regret-regret-regret","status":"publish","type":"post","link":"https:\/\/blogs.oregonstate.edu\/sandfield\/2021\/10\/22\/regret-regret-regret\/","title":{"rendered":"Regret Regret Regret"},"content":{"rendered":"\n
\"Prophet<\/figure><\/div>\n\n\n\n

Regret is a strong word. I have regrets. Monoliths have their advantages, and I am rapidly and repeatedly finding them as I implement a microservice ecosystem for the first time. This week I set out to define the gateway API and dummy routes in the user service to experiment with multi-layer API calls. Then I sat down and realized that in order to talk to each other, the services each needed to know where the others were. I could<\/em> hardcode URLs and rely on everything working perfectly and never changing; you already know why that’s a bad idea. I could<\/em> have the gateway service pull double duty and have it’s<\/em> address hardcoded into all other services; this would disobey a core principle of microservice philosophy and not actually save any trouble vs doing it properly.<\/p>\n\n\n\n

\"Pooh<\/figure><\/div>\n\n\n\n

So I now have a new coordinator service which will have its address provided via config files in all the other microservices and will be queried to retrieve the URLs for services of interest. I also got to learn how to create and use a custom Node module in order to keep to DRY principles; if every microservice is going to need to talk to the coordinator, then there needs to be a standardized block of code that I don’t need to worry about fixing everywhere any time it needs a fix.<\/p>\n\n\n\n

Starting with the module, it turns out that the basic documentation<\/a> is really all that was needed to actually do the module-specific pieces, although what they don’t tell you is that the ability to publish a private module requires a premium subscription. The module code was also pretty simple; private variables to store the needed URLs, setters for the coordinator URL and other service URLs, and two layers of getters for a service URL – if it is already stored and by making a query to the coordinator if it isn’t. Testing is where the real fun was. I finally got to knock out some Nock, and I had to pull on a new tutorial<\/a> on top of what I’ve linked in the past. Setting up the dummy routes wasn’t actually so bad, but interfacing it with Chai and the request module proved to be a hassle. Request has been deprecated, so I needed to sift through a decade of now out of date information, the HTTPS just did not give me any compatible output, and so I settled on Axios as a module that I’ve used in the past. Even then, it took a couple hours of trial and error with the Chai documentation to get the async tests to validate correctly without timing out.<\/p>\n\n\n\n

Then there was the matter of the coordinator service itself. Again, easy to code but a pain to figure out correct testing. There’s just the GETter and SETer routes and supporting model functions but I still don’t have a handle on Chai. Several timeouts, errors, and false test passes later I got to here:<\/p>\n\n\n\n

describe('\/POST service', function() {<\/code>
it('should return a 201 status with self address attached', function(done) {<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 chai.request(app)<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 .post('\/services\/' + serviceName)<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 .end((err, res) => {<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 res.should.have.status(201);<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 let address = res.body[serviceName];<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 address.substr(0, address.indexOf(\":\")).should.be.an.ip;<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 done();<\/code>
\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 });<\/code>
\u00a0 \u00a0 })<\/code>;
});<\/code><\/p>\n\n\n\n

The major lessons learned to make it work:<\/p>\n\n\n\n