It works!

tor/Dockerfile

@@ -0,0 +1,20 @@
+FROM alpine
+
+ARG SVC_HOST
+ARG SVC_PORT
+
+WORKDIR /etc/tor
+
+RUN apk add --no-cache curl tor && \
+    echo -e "HiddenServiceDir /var/lib/tor/svc/\nHiddenServicePort $SVC_PORT $SVC_HOST:$SVC_PORT" > ./torrc
+
+HEALTHCHECK --interval=60s --timeout=15s --start-period=20s \
+    CMD curl -s --socks5 127.0.0.1:9050 'https://check.torproject.org/' | grep -qm1 Congratulations
+
+COPY tor.sh /usr/bin/
+
+#VOLUME ["/var/lib/tor/svc"]
+
+#USER tor
+
+CMD ["tor.sh"]

tor/tor.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+IP_BROKER=$(nslookup broker | awk '/^Address: / { print $2 }' | tail -n1 | sed -e 's/[[:space:]]//g')
+sed -i "s/broker/$IP_BROKER/g" /etc/tor/torrc
+tor