Add postgres complement support (#2177)

build/scripts/ComplementPostgres.Dockerfile

@@ -0,0 +1,53 @@
+FROM golang:1.16-stretch as build
+RUN apt-get update && apt-get install -y postgresql
+WORKDIR /build
+
+# No password when connecting over localhost
+RUN sed -i "s%127.0.0.1/32            md5%127.0.0.1/32            trust%g" /etc/postgresql/9.6/main/pg_hba.conf && \
+    # Bump up max conns for moar concurrency
+    sed -i 's/max_connections = 100/max_connections = 2000/g' /etc/postgresql/9.6/main/postgresql.conf
+
+# This entry script starts postgres, waits for it to be up then starts dendrite
+RUN echo '\
+#!/bin/bash -eu \n\
+pg_lsclusters \n\
+pg_ctlcluster 9.6 main start \n\
+ \n\
+until pg_isready \n\
+do \n\
+  echo "Waiting for postgres"; \n\
+  sleep 1; \n\
+done \n\
+' > run_postgres.sh && chmod +x run_postgres.sh
+
+# we will dump the binaries and config file to this location to ensure any local untracked files
+# that come from the COPY . . file don't contaminate the build
+RUN mkdir /dendrite
+
+# Utilise Docker caching when downloading dependencies, this stops us needlessly
+# downloading dependencies every time.
+COPY go.mod .
+COPY go.sum .
+RUN go mod download
+
+COPY . .
+RUN go build -o /dendrite ./cmd/dendrite-monolith-server
+RUN go build -o /dendrite ./cmd/generate-keys
+RUN go build -o /dendrite ./cmd/generate-config
+
+WORKDIR /dendrite
+RUN ./generate-keys --private-key matrix_key.pem
+
+ENV SERVER_NAME=localhost
+EXPOSE 8008 8448
+
+
+# At runtime, generate TLS cert based on the CA now mounted at /ca
+# At runtime, replace the SERVER_NAME with what we are told
+CMD /build/run_postgres.sh && ./generate-keys --server $SERVER_NAME --tls-cert server.crt --tls-key server.key --tls-authority-cert /complement/ca/ca.crt --tls-authority-key /complement/ca/ca.key && \
+ ./generate-config -server $SERVER_NAME --ci > dendrite.yaml && \
+ # Replace the connection string with a single postgres DB, using user/db = 'postgres' and no password, bump max_conns
+ sed -i "s%connection_string:.*$%connection_string: postgresql://postgres@localhost/postgres?sslmode=disable%g" dendrite.yaml && \
+ sed -i 's/max_open_conns:.*$/max_open_conns: 100/g' dendrite.yaml && \
+ cp /complement/ca/ca.crt /usr/local/share/ca-certificates/ && update-ca-certificates && \
+ ./dendrite-monolith-server --tls-cert server.crt --tls-key server.key --config dendrite.yaml