reorganize dockerfile for better build cache usage

also lock some versions

ideally I wouldn't have to copy each of these directories separately and
have a janky stage to hide all the resulting layers, but docker do be like that.
`COPY dir1 dir2 ./` copies *the contents of* dir1 and dir2 to the
working directory :(

maybe one day i will switch to having a src directory

Dockerfile

@@ -1,14 +1,32 @@
-FROM python:3 AS builder
+FROM python:3.10-bullseye AS deps
 WORKDIR /usr/src/app
-COPY . .
 
-# install python stuff
-RUN python -m pip install --upgrade pip
+RUN python -m pip install --upgrade pip==22.2.2
+RUN apt-get update -qq && apt-get install -qq nodejs npm
+
+COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# build assets
-RUN apt-get update -qq && apt-get install -qq nodejs npm
+COPY package.json package-lock.json ./
 RUN npm install --save-dev
+
+
+FROM scratch AS layer-cake
+WORKDIR /
+
+COPY *.py setup.cfg rollup.config.js ./
+COPY assets assets
+COPY components components
+COPY libforget libforget
+COPY migrations migrations
+COPY routes routes
+COPY static static
+COPY templates templates
+
+
+FROM deps
+
+COPY --from=layer-cake / ./
 RUN doit
 
 VOLUME ["/var/run/celery"]