I've been learning Travis CI and I want to use it to help automate tests on a MEAN application, then deploy it. However, there are some ways to go about this.
After reading, I learned I can create two separate repositories, thus maintaining two separate applications: a client application and a backend application. Since they are separate repositories, I can have separate .travis.yml files on each and perform continuous integration on the client application and backend application. However, I need advice on this approach because I have questions:
For the client app, I have to write tests. Since I'll be using angular, I want to test responsiveness and if components are working as intended. The client application also has to communicate with the backend application and I want to see if it is properly getting the correct results (such as clicking a button triggers a GET request and see if I'm getting the correct response body). Since the client app is on a separate repository, and when I build it on TravisCI, how will I connect the client application to the backend application if it exists on a separate repository?
I read around and I can use submodules in git. Thus, the client application and the backend application can be submodules for a 'master repository'. Therefore, how will the trigger in TravisCI work? Will I have separate travis.yml files in each submodule, or will I have to have one in the "master repository"?
If I were to get everything to work properly and have the client application and backend application both successfully deploy and the two are hosted on different servers, how will I fix the cross-domain issue?
The other approach is to host the static files produced by ng build --prod and have the node backend application host them. When Travis CI is triggered, I can first build the node backend application and run the tests on it first and then run the tests on the angular client application. After all of the tests are passed, where do I deploy? I know I have to deploy the node application since it will host the static files, so I how exactly will I deploy the backend application in Travis CI?
I know this is going to push it, but I'll ask it anyway. In the future, I want to learn how to implement microservices, and I want to use Nginx for the purpose of load balancing. How will I go about that? Docker can help me create a production environment where I can see if the Nginx server and node application are working well, but how do I include that in Travis CI?
If my question is a bit vague, please let me know what parts of it are vague so I can edit it that way I can make more sense of what I'm asking for. Thank you, and I look forward to an answer :)
Question is ultra-broad. You should solve one problem at a time, because by the time you solve 1 and 2 I doubt that 3 will be your only concern, and all of these issues are not really related.
try spending a bit of time reading Travis CI documentation, but also how to write tests and what different types of tests will do for you. Your issue is less about Travis than about what are unit tests vs. what are integration tests. So write simple standalone tests for your frontend, simple standalone tests for your backend, maybe run integration tests manually for a while, and when it becomes a real issue, then you will have better knowledge of how everything works together and you will find a way. Long story short: there is no single best way to run integration tests and it mostly depends on many, many things in your app (how does it run, what type of DB do you use, etc.)
you should read about submodules. Perhaps you need them, perhaps not. There is no way to tell. You can use submodules with Travis CI, but you can also not use submodules. Depends on what you want to achieve. Focus on the end goal for your architecture, not on what Travis CI needs!
what cross-domain issue? Again, this is a very different problem, and probably not the most prominent one you will face. Since I have no idea what server technology you will use there is no way I can answer that question properly. If you use express, this may be what you are looking for: https://expressjs.com/en/resources/middleware/cors.html
General bit of advice: all of your questions boil down to experience. Try solving one problem at a time, get started with your project and when you hit a specific issue, it's much much easier to solve than asking about "microservices". There are many ways to do microservices right, each solving a different issue. Without any knowledge of what your application is about and what issues you want to solve, microservices may or may not be what you are looking for, but there are also many other components that can affect your stack. Just get started and don't think about all of this too much for now - it's better to have something soon that you can test and learn upon, than think for weeks about something that you will never get because it is only theory.