build: setup docker-compose.dev.yml dev iteration

This is based off of the 5-commit branch at
https://github.com/neobooru/szurubooru/blob/docker-development-setup.

Compared to said branch, we
* Exclude extraneous changes such as
    * Any formatting
    * The use of deprecated/ineffectual top-level `version:` in composer files
* Support controlling $THREADS (modernizing the branch to upstream)
* Integrate into master more cleanly

However, client/docker-start-dev uses a temporary hack -- due to
volume mounting overwriting node_modules at arbitrary points during the
`docker compose build` step, we run `npm i` before any given
`npm run watch`.

To see the effects of this commit in action, run:

    docker compose -f ./docker-compose.dev.yml up

client/.dockerignore

@@ -1,4 +1,5 @@
 node_modules/*
+public/
 Dockerfile
 .dockerignore
 **/.gitignore

client/Dockerfile

@@ -1,3 +1,26 @@
+FROM --platform=$BUILDPLATFORM node:lts-alpine as development
+WORKDIR /opt/app
+
+RUN apk --no-cache add \
+    dumb-init \
+    nginx \
+    git
+
+RUN ln -sf /opt/app/nginx.conf.docker /etc/nginx/nginx.conf
+RUN rm -rf /var/www
+RUN ln -sf /opt/app/public/ /var/www
+
+COPY package.json package-lock.json ./
+RUN npm install
+
+ARG BUILD_INFO="docker-development"
+ENV BUILD_INFO=${BUILD_INFO}
+ENV BACKEND_HOST="server"
+
+CMD ["/opt/app/docker-start-dev.sh"]
+VOLUME ["/data"]
+
+
 FROM --platform=$BUILDPLATFORM node:lts as builder
 WORKDIR /opt/app
 

client/build.js

@@ -315,7 +315,7 @@ function makeOutputDirs() {
 }
 
 function watch() {
-    let wss = new WebSocket.Server({ port: 8080 });
+    let wss = new WebSocket.Server({ port: environment === "development" ? 8081 : 8080 });
     const liveReload = !process.argv.includes('--no-live-reload');
 
     function emitReload() {

client/docker-start-dev.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/dumb-init /bin/sh
+
+# Integrate environment variables
+sed -i "s|__BACKEND__|${BACKEND_HOST}|" \
+  /etc/nginx/nginx.conf
+
+# Start server
+nginx &
+
+# Watch source for changes and build app
+# FIXME: It's not ergonomic to run `npm i` outside of the build step.
+#        However, the mounting of different directories into the
+#        client container's /opt/app causes node_modules to disappear
+#          (the mounting causes client/Dockerfile's RUN npm install
+#           to silently clobber).
+#        Find a way to move `npm i` into client/Dockerfile.
+npm i && npm run watch -- --polling

client/docker-start.sh

@@ -2,10 +2,10 @@
 
 # Integrate environment variables
 sed -i "s|__BACKEND__|${BACKEND_HOST}|" \
-    /etc/nginx/nginx.conf
+  /etc/nginx/nginx.conf
 sed -i "s|__BASEURL__|${BASE_URL:-/}|g" \
-    /var/www/index.htm \
-    /var/www/manifest.json
+  /var/www/index.htm \
+  /var/www/manifest.json
 
 # Start server
 exec nginx

client/js/main.js

@@ -3,7 +3,7 @@
 const config = require("./config.js");
 
 if (config.environment == "development") {
-    var ws = new WebSocket("ws://" + location.hostname + ":8080");
+    var ws = new WebSocket("ws://" + location.hostname + ":8081");
     ws.addEventListener("open", function (event) {
         console.log("Live-reloading websocket connected.");
     });