document self-hosting

README.md

@@ -45,4 +45,49 @@ Represents an IDS level.
 
 - `tier`: `"Fuck"`, `"Beginner"`, `"Easy"`, `"Medium"`, `"Hard"`, `"Very Hard"`, `"Insane"` or `"Extreme"`.
 - `skillset`: Level skillset, as listed on the sheet.
-- `broken`: If the level is broken in 2.2. `"no"`, `"yes"`, or rarely `null` if unknown.
+- `broken`: If the level is broken in 2.2. `"no"`, `"yes"`, or rarely `null` if unknown.
+
+### Self-hosting
+
+You can self-host the API yourself, if you so wish! Here's the rough steps:
+
+1. Grab yourself a Google Sheets API key. This may sound extremely intimidating, but you can create a read-only Sheets API key with not much hassle with [this guide](https://theoephraim.github.io/node-google-spreadsheet/#/guides/authentication?id=api-key).
+2. Install, either with NPM or Nix:
+    1. With NPM, run:
+        ```sh
+        npm install
+        ```
+        Then, you can start it with:
+        ```sh
+        API_KEY=... node index.js
+        ```
+        **However**, take note of the [environment variables](#environment-variables) available to use.
+    2. Use Nix to either just plainly run it:
+        ```sh
+        API_KEY=... nix run git+https://git.oat.zone/oat/nlw-api
+        ```
+        Or import it into your system flake like so:
+        ```nix
+        nlw-api.url = "git+https://git.oat.zone/oat/nlw-api";
+        # in your `nixosConfiguration`:
+        imports = [
+          inputs.nlw-api.nixosModules.nlw-api
+        ];
+        ```
+        Afterwards, you can use it as a regular NixOS service:
+        ```nix
+        services.nlw-api = {
+          enable = true;
+          domain = "nlw.oat.zone";
+          apiKey = builtins.readFile /etc/sheets-api-key;
+          port = 1995;
+        };
+        ```
+3. You're done! It will take a while to fetch every level and their IDs initially, but in time you will have yourself the caches set up and the server up and running.
+   
+### Environment variables
+
+You can pass these into the server as config (an `.env` file will **not** work):
+
+- `API_KEY`: A Google API key - see [this guide](https://theoephraim.github.io/node-google-spreadsheet/#/guides/authentication?id=api-key) to see how to get one hassle-free
+- `PORT`: The HTTP port to host the server on