Merge the Complement testing Docker images into a single, multi-purpose image. (#12881)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

docker/complement/Dockerfile

@@ -1,22 +1,45 @@
-# A dockerfile which builds an image suitable for testing Synapse under
-# complement.
-
+# This dockerfile builds on top of 'docker/Dockerfile-workers' in matrix-org/synapse
+# by including a built-in postgres instance, as well as setting up the homeserver so
+# that it is ready for testing via Complement.
+#
+# Instructions for building this image from those it depends on is detailed in this guide:
+# https://github.com/matrix-org/synapse/blob/develop/docker/README-testing.md#testing-with-postgresql-and-single-or-multi-process-synapse
 ARG SYNAPSE_VERSION=latest
+FROM matrixdotorg/synapse-workers:$SYNAPSE_VERSION
 
-FROM matrixdotorg/synapse:${SYNAPSE_VERSION}
+# Install postgresql
+RUN apt-get update && \
+  DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y postgresql-13
 
-ENV SERVER_NAME=localhost
+# Configure a user and create a database for Synapse
+RUN pg_ctlcluster 13 main start &&  su postgres -c "echo \
+ \"ALTER USER postgres PASSWORD 'somesecret'; \
+ CREATE DATABASE synapse \
+  ENCODING 'UTF8' \
+  LC_COLLATE='C' \
+  LC_CTYPE='C' \
+  template=template0;\" | psql" && pg_ctlcluster 13 main stop
 
-COPY conf/* /conf/
-
-# generate a signing key
-RUN generate_signing_key -o /conf/server.signing.key
+# Extend the shared homeserver config to disable rate-limiting,
+# set Complement's static shared secret, enable registration, amongst other
+# tweaks to get Synapse ready for testing.
+# To do this, we copy the old template out of the way and then include it
+# with Jinja2.
+RUN mv /conf/shared.yaml.j2 /conf/shared-orig.yaml.j2
+COPY conf/workers-shared-extra.yaml.j2 /conf/shared.yaml.j2
 
 WORKDIR /data
 
+COPY conf/postgres.supervisord.conf /etc/supervisor/conf.d/postgres.conf
+
+# Copy the entrypoint
+COPY conf/start_for_complement.sh /
+
+# Expose nginx's listener ports
 EXPOSE 8008 8448
 
-ENTRYPOINT ["/conf/start.sh"]
+ENTRYPOINT ["/start_for_complement.sh"]
 
+# Update the healthcheck to have a shorter check interval
 HEALTHCHECK --start-period=5s --interval=1s --timeout=1s \
-    CMD curl -fSs http://localhost:8008/health || exit 1
+    CMD /bin/sh /healthcheck.sh