feat: Add FastAPI s6 sidecar PoC

- Sidecar DragonflyDB as Redis replacement
- Run pytheus in multiprocessing mode with Redis backend

Dockerfile

@@ -0,0 +1,38 @@
+FROM public.ecr.aws/docker/library/python:3.11-slim-bookworm
+ARG S6_OVERLAY_VERSION=3.1.5.0
+
+RUN apt-get update && apt-get upgrade -y && apt-get install -y xz-utils libssl-dev libxml2-dev && rm -rf /var/cache/apt/archives /var/lib/apt/lists
+
+# Add s6-overlay
+ADD https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-noarch.tar.xz /tmp
+RUN tar -C / -Jxpf /tmp/s6-overlay-noarch.tar.xz
+ADD https://github.com/just-containers/s6-overlay/releases/download/v${S6_OVERLAY_VERSION}/s6-overlay-x86_64.tar.xz /tmp
+RUN tar -C / -Jxpf /tmp/s6-overlay-x86_64.tar.xz
+
+# Add FastAPI s6 config
+RUN mkdir -p /etc/s6-overlay/s6-rc.d/fastapi/dependencies.d/
+RUN echo "longrun" >> /etc/s6-overlay/s6-rc.d/fastapi/type
+COPY s6/run_fastapi /etc/s6-overlay/s6-rc.d/fastapi/run
+RUN touch /etc/s6-overlay/s6-rc.d/user/contents.d/fastapi && touch /etc/s6-overlay/s6-rc.d/fastapi/dependencies.d/base && touch /etc/s6-overlay/s6-rc.d/fastapi/dependencies.d/dragonfly
+
+# Install DragonflyDB
+ADD https://github.com/dragonflydb/dragonfly/releases/download/v1.7.1/dragonfly_amd64.deb /tmp
+RUN dpkg -i /tmp/dragonfly_amd64.deb
+
+# Cleanup /tmp
+RUN rm -rf /tmp/*
+
+# Add DragonflyDB s6 config
+RUN mkdir -p /etc/s6-overlay/s6-rc.d/dragonfly/dependencies.d/
+RUN echo "longrun" >> /etc/s6-overlay/s6-rc.d/dragonfly/type
+COPY s6/run_dragonfly /etc/s6-overlay/s6-rc.d/dragonfly/run
+RUN touch /etc/s6-overlay/s6-rc.d/user/contents.d/dragonfly && touch /etc/s6-overlay/s6-rc.d/dragonfly/dependencies.d/base
+
+# Add FastAPI code + dependencies
+WORKDIR /code
+COPY ./requirements.txt /code/requirements.txt
+RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt
+COPY ./app /code/app
+
+# Execute s6 overlay entrypoint
+ENTRYPOINT ["/init"]