feat: run PostgreSQL instance in background (database-lab#141)

Author: agneum

sync-instance/Dockerfile

@@ -10,10 +10,16 @@ ENV WALG_VERSION=${WALG_VERSION:-0.2.15}
 
 # Install dependecies.
 RUN apt-get update \
-    && apt-get install --no-install-recommends -y ca-certificates wget daemontools \
+    && apt-get install --no-install-recommends -y ca-certificates wget daemontools sudo \
     && wget --quiet -O /tmp/wal-g.linux-amd64.tar.gz "https://github.com/wal-g/wal-g/releases/download/v${WALG_VERSION}/wal-g.linux-amd64.tar.gz" \
     && tar -zxvf /tmp/wal-g.linux-amd64.tar.gz && mv wal-g /usr/local/bin/ \
     && rm -rf /tmp/* \
     && apt-get purge -y --auto-remove \
     && apt-get clean -y autoclean \
     && rm -rf /var/lib/apt/lists/*
+
+# Prepare Postgres start script.
+RUN echo "#!/bin/bash" > /pg_start.sh && chmod a+x /pg_start.sh \
+    && echo "/bin/bash -c \"trap : TERM INT; sleep infinity & wait\"" >> /pg_start.sh
+
+CMD ["/pg_start.sh"]