Update and add support for Prometheus metrics

Dockerfile

@@ -37,7 +37,7 @@ ENV RUSTFLAGS "-C link-arg=-s"
 RUN apt-get update && apt-get install -qy --no-install-recommends $BUILD_DEPS && \
     curl -sSf https://sh.rustup.rs | bash -s -- -y --default-toolchain nightly && \
     export PATH="$HOME/.cargo/bin:$PATH" && \
-    echo "Compiling encrypted-dns version 0.3.3" && \
+    echo "Compiling encrypted-dns version 0.3.5" && \
     cargo install encrypted-dns && \
     mkdir -p /opt/encrypted-dns/sbin && \
     mv ~/.cargo/bin/encrypted-dns /opt/encrypted-dns/sbin/ && \
@@ -73,7 +73,7 @@ COPY watchdog.sh /etc/service/watchdog/run
 
 VOLUME ["/opt/encrypted-dns/etc/keys"]
 
-EXPOSE 443/udp 443/tcp
+EXPOSE 443/udp 443/tcp 9100/tcp
 
 CMD ["/entrypoint.sh", "start"]
 

README.md

@@ -149,6 +149,13 @@ TLS (including HTTPS and DoH) forwarding
 
 If the DNS server is listening to port `443`, but you still want to have a web (or DoH) service accessible on that port, add the `-T` switch followed by the backend server IP and port to the `init` command (for example: `-T 10.0.0.1:4443`).
 
+Prometheus metrics
+==================
+
+Metrics are accessible inside the container as http://127.0.0.1:9100/metrics.
+
+They can be made accessible outside of the container by adding the `-M` option followed by the IP and port (for example: `-M 0.0.0.0:9100`).
+
 Join the network
 ================
 

encrypted-dns.toml.in

@@ -50,10 +50,10 @@ udp_max_active_connections = 1000
 tcp_max_active_connections = 100
 
 
-## IP address to connect to upstream servers from.
-## You probably do not want to change this. `0.0.0.0` should be fine.
+## Optional IP address to connect to upstream servers from.
+## Leave commented/undefined to automatically select it.
 
-external_addr = "0.0.0.0"
+# external_addr = "0.0.0.0"
 
 
 ## Built-in DNS cache capacity
@@ -168,12 +168,11 @@ key_cache_capacity = 10000
 #        Metrics        #
 #########################
 
-# [metrics]
-
-# type = "prometheus"
-# listen_addr = "0.0.0.0:9100"
-# path = "/metrics"
+[metrics]
 
+type = "prometheus"
+listen_addr = "@METRICS_ADDRESS@"
+path = "/metrics"
 
 
 ################################
@@ -199,4 +198,4 @@ allow_non_reserved_ports = false
 
 # Blacklisted upstream IP addresses
 
-blacklisted_ips = [ @ANONDNS_BLACKLISTED_IPS@ ]
+blacklisted_ips = [ @ANONDNS_BLACKLISTED_IPS@ ]

entrypoint.sh

@@ -14,8 +14,6 @@ CONF_DIR="/opt/encrypted-dns/etc"
 CONFIG_FILE="${CONF_DIR}/encrypted-dns.toml"
 CONFIG_FILE_TEMPLATE="${CONF_DIR}/encrypted-dns.toml.in"
 
-# -N provider-name -E external-ip-address:port
-
 init() {
     if [ "$(is_initialized)" = yes ]; then
         start
@@ -25,13 +23,16 @@ init() {
     anondns_enabled="false"
     anondns_blacklisted_ips=""
 
-    while getopts "h?N:E:T:A" opt; do
+    metrics_address="127.0.0.1:9100"
+
+    while getopts "h?N:E:T:AM:" opt; do
         case "$opt" in
         h | \?) usage ;;
         N) provider_name=$(echo "$OPTARG" | sed -e 's/^[ \t]*//' | tr A-Z a-z) ;;
         E) ext_address=$(echo "$OPTARG" | sed -e 's/^[ \t]*//' | tr A-Z a-z) ;;
         T) tls_proxy_upstream_address=$(echo "$OPTARG" | sed -e 's/^[ \t]*//' | tr A-Z a-z) ;;
         A) anondns_enabled="true" ;;
+        M) metrics_address=$(echo "$OPTARG" | sed -e 's/^[ \t]*//' | tr A-Z a-z) ;;
         esac
     done
     [ -z "$provider_name" ] && usage
@@ -73,6 +74,7 @@ init() {
         -e "s#@DOMAIN_BLACKLIST_CONFIGURATION@#${domain_blacklist_configuration}#" \
         -e "s#@ANONDNS_ENABLED@#${anondns_enabled}#" \
         -e "s#@ANONDNS_BLACKLISTED_IPS@#${anondns_blacklisted_ips}#" \
+        -e "s#@METRICS_ADDRESS@#${metrics_address}#" \
         "$CONFIG_FILE_TEMPLATE" >"$CONFIG_FILE"
 
     mkdir -p -m 700 "${STATE_DIR}"