From edee44d8e12b2ca76607dd1c438d62e362f44f51 Mon Sep 17 00:00:00 2001
From: Fang Yi Liu <fangyiliu@gmail.com>
Date: Tue, 9 Jul 2024 16:57:09 -0700
Subject: [PATCH] docs: how to switch back to debian docker image

---
 docs/tools/docker.md | 84 ++++++++++++++++++++++++++++++++++++++++++++
 mkdocs.yml           |  3 ++
 2 files changed, 87 insertions(+)

diff --git a/docs/tools/docker.md b/docs/tools/docker.md
index 749a57b3..ac49299e 100644
--- a/docs/tools/docker.md
+++ b/docs/tools/docker.md
@@ -23,3 +23,87 @@ For apt, the cache directory is `/var/cache/apt/`.
     - [proper usage of mount cache](https://dev.doroshev.com/blog/docker-mount-type-cache/)
     - [mount cache reference](https://docs.docker.com/engine/reference/builder/#run---mounttypecache)
     - [buildkit dockerfile reference](https://github.com/moby/buildkit/blob/master/frontend/dockerfile/docs/reference.md)
+
+## Alpine vs Debian based images
+
+We're choosing to use an Alpine-based image for the smaller size and faster builds and downloads. However, a Debian-based image has the advantage of a large ecosystem of available packages, a limitation of Alpine that we may run up against in the future.
+
+### Switching to Debian
+
+Here is how we can switch to a Debian-based images if we need to:
+
+1. Edit `Dockerfile` to look something like this
+
+    ```Dockerfile title="app/Dockerfile"
+
+    # pull official base image
+    {--FROM python:3.10-alpine--}
+    # (1)! define base image
+    {++FROM python:3.10-bullseye++}
+
+    # set work directory
+    WORKDIR /usr/src/app
+
+    # set environment variables
+    ENV PYTHONDONTWRITEBYTECODE=1
+    ENV PYTHONUNBUFFERED=1
+    {++ENV PYTHONPYCACHEPREFIX=/root/.cache/pycache/++}
+    {++ENV PIP_CACHE_DIR=/var/cache/buildkit/pip++}
+
+    {++RUN mkdir -p $PIP_CACHE_DIR++}
+    # (2)! prevent cache deletion
+    {++RUN rm -f /etc/apt/apt.conf.d/docker-clean; \ ++}
+    {++echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/keep-cache++}
+
+    # install system dependencies
+    RUN \
+    {--  --mount=type=cache,target=/var/cache/apk \ --}
+    {--  --mount=type=cache,target=/etc/apk/cache \ --}
+    {--  apk add \--}
+    {--  'graphviz=~9.0'--}
+
+    {--# install font for graphviz--}
+    {--COPY Roboto-Regular.ttf /root/.fonts/--}
+    {--RUN fc-cache -f--}
+    # (3)! define cache mounts and install dependencies
+    {++  --mount=type=cache,target=/var/cache/apt,sharing=locked \ ++}
+    {++  --mount=type=cache,target=/var/lib/apt,sharing=locked \ ++}
+    {++  apt-get update \ ++}
+    {++  && apt-get install --no-install-recommends -yqq \ ++}
+    {++  netcat=1.10-46 \ ++}
+    {++  gcc=4:10.2.1-1 \ ++}
+    {++  postgresql=13+225+deb11u1 \ ++}
+    {++  graphviz=2.42.2-5++}
+
+    # install dependencies
+    COPY ./requirements.txt .
+    # hadolint ignore=DL3042
+    # (4)! install uv for faster dependency resolution
+    RUN \
+      --mount=type=cache,target=/root/.cache \
+      pip install uv==0.1.15 \
+      && uv pip install --system -r requirements.txt
+
+    # copy entrypoint.sh
+    COPY ./entrypoint.sh .
+    RUN sed -i 's/\r$//g' /usr/src/app/entrypoint.sh \
+      && chmod +x /usr/src/app/entrypoint.sh
+
+    # copy project
+    COPY . .
+
+    # run entrypoint.sh
+    ENTRYPOINT ["/usr/src/app/entrypoint.sh"]
+    ```
+
+    1. define base image
+    1. prevent cache deletion
+    1. install system dependencies
+        1. define cache mounts for apt and lib
+        1. install netcat for db wait script, which is used in `entrypoint.sh`
+        1. install gcc for python local compiling, which shouldn't be needed
+        1. install postgresql for `dbshell` management command
+        1. install graphviz for generating ERD in `erd.sh`
+    1. install uv for faster dependency resolution, which may or may not be wanted
+
+1. Use the `dive` tool to check the image layers for extra files that shouldn't be there.
diff --git a/mkdocs.yml b/mkdocs.yml
index 7e8d05c7..d5ebcd49 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -7,6 +7,7 @@ theme:
   name: material
   features:
     - content.action.edit
+    - content.action.view
     - content.code.annotate
     - content.code.copy
     - content.code.select
@@ -27,6 +28,8 @@ markdown_extensions:
   - md_in_html
   - pymdownx.betterem
   - pymdownx.blocks.details
+  - pymdownx.critic:
+      mode: view
   - pymdownx.details
   - pymdownx.highlight:
       anchor_linenums: true