Initial code dump: matrix feedbot, aka bender

This is a rewrite of our old feedbot in rust, heavily inspired from
rek2's INN matrix bot and making use of some bits from matrix-rust-sdk

This is an asynchronous tokio-based matrix client using a stateless feed
fetcher implementation based on reqwest, it uses feed_rs for parsing RSS
and Atom feeds. State persistence is achieved using a simple file-backed
datastore with serde_yaml as a serialization format.

Published under the GNU General Public License version 3 or later.

Dockerfile

@@ -0,0 +1,25 @@
+FROM rust:1.82.0-slim-bookworm AS build
+
+RUN USER=root cargo new --bin matrix-feedbot
+WORKDIR /matrix-feedbot
+
+COPY Cargo.lock ./
+COPY Cargo.toml ./
+
+RUN apt-get update && apt-get install -y --no-install-recommends libssl-dev pkg-config
+
+# cache dependencies
+RUN cargo build --release
+RUN rm src/*.rs
+
+COPY src ./src
+
+RUN rm target/release/deps/matrix_feedbot*
+RUN cargo build --release
+
+FROM debian:bookworm-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends libssl3 && apt-get clean
+COPY --from=build /matrix-feedbot/target/release/matrix-feedbot .
+
+CMD ["./matrix-feedbot"]