# Developer Guide #

This is a generic "getting started" guide for the uxbox platform. It
intends to explain how to get the development environment up and
running with many additional tips.

The main development environment consists in a docker compose
configuration that starts the external services and the development
container (called **devenv**).

We use tmux script in order to multiplex the single terminal and run
both the backend and frontend in the same container.


## System requirements ##

You should have `docker` and `docker-compose` installed in your system
in order to set up properly the development enviroment.

In debian like linux distributions you can install it executing:

```bash
sudo apt-get install docker docker-compose
```

Start and enable docker environment:


```bash
sudo systemctl start docker
sudo systemctl enable docker
```

Add your user to the docker group:

```basb
sudo usermod -aG docker $USER
```

And finally, increment user watches:

```
echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p
```

NOTE: you probably need to login again for group change take the effect.


## Start the devenv ##

**Requires a minimum knowledge of tmux usage in order to use that
development environment.**

For start it, staying in this repository, execute:

```bash
./manage.sh run-devenv
```

This will do the following:

- Build the images if it is not done before.
- Starts all the containers in the background.
- Attaches to the **devenv** container and executes the tmux session.
- The tmux session automatically starts all the necessary services.

You can execute the individual steps manully if you want:

```bash
./manage.sh build-devenv # builds the devenv docker image
./manage.sh start-devenv # starts background running containers
./manage.sh run-devenv   # enters to new tmux session inside of one of the running containers
./manage.sh stop-devenv  # stops background running containers
./manage.sh drop-devenv  # removes all the volumes, containers and networks used by the devenv
```

Now having the the container running and tmux open inside the
container, you are free to execute any commands and open many shells
as you want.

You can create a new shell just pressing the **Ctr+b c** shortcut. And
**Ctrl+b w** for switch between windows, **Ctrl+b &** for kill the
current window.

For more info: https://tmuxcheatsheet.com/


### Inside the tmux session

#### gulp

The styles and many related tasks are executed thanks to gulp and they are
executed in the tmux **window 0**. This is a normal gulp watcher with some
additional tasks.


#### shadow-cljs

The frontend build process is located on the tmux **window 1**.
**Shadow-cljs** is used for build and serve the frontend code. For
more information, please refer to `02-Frontend-Developer-Guide.md`.

By default the **window 1** executes the shadow-cljs watch process,
that starts a new JVM/Clojure instance if there is no one running.

Finally, you can start a REPL linked to the instance and the current
connected browser, by opening a third window with `Ctrl+c` and running
`npx shadow-cljs cljs-repl main`.


#### exporter

The exporter app (clojurescript app running in nodejs) is located in
**window 2**, and you can go directly to it using `ctrl+b 2` shortcut.

There you will found the window split in two slices. On the top slice
you will have the build process (using shadow-cljs in the same way as
frontend application), and on the bot slice the script that launeches
the node process.

If some reason scripts does not stars correctly, you can manually
execute `node target/app.js ` to start the exporter app.


#### backend

The backend related environment is located in the tmux **window 3**,
and you can go directly to it using `ctrl+b 2` shortcut.

By default the backend will be started in non-interactive mode for
convenience but you can just press `Ctrl+c` and execute `./scripts/repl`
for start the repl.

On the REPL you have this helper functions:
- `(start)`: start all the environment
- `(stop)`: stops the environment
- `(restart)`: stops, reload and start again.

And many other that are defined in the `tests/user.clj` file.

If some exception is raised when code is reloaded, just use
`(repl/refresh-all)` in order to finish correctly the code swaping and
later use `(restart)` again.

For more information, please refer to: `03-Backend-Guide.md`.


## Start the testenv ##

The purpose of the testenv (Test Environment) is provide an easy way
to get uxbox running in local pc without getting into the full
development environment.

As first step we still need to build devenv image because that image
is used to produce the production-like bundle of the application:

```bash
./manage.sh build-devenv
```

Once the image is build, you no longer need to rebuilt it until the
devenv image is changed and this happens we make some structural
changes or upgrading some dependencies.

Them, let's proceed to build the bundle (a directory that contains all
the sources and dependencies of the platform ready to be deployed):

```bash
./manage.sh build-bundle
```

This will generate on current directory one file and one
directory. The most important is the file like
`uxbox-2020.09.09-1343.tar.xz`.

Then, let's proceed to build the docker images with the bundle
generated from the previous step.

```bash
./manage.sh build-testenv ./uxbox-2020.09.09-1343.tar.xz
```

This will generate the necessary docker images ready to be executed.

And finally, start the docker-compose:

```bash
./manage.sh start-devenv
```