Add a setting for load balancer IPs.

README.md

@@ -209,6 +209,13 @@ putting it in `/opt/docker/zulip/zulip/certs/` (by default, the
 `zulip` container startup script will generate a self-signed certificate and
 install it in that directory).
 
+**Load balancer**. To tell Zulip it's behind a load balancer, you can set
+`LOADBALANCER_IPS` to a comma-separated list of IPs. This will tell Zulip
+to pass the real IP of the client instead of the IP of the load balancer itself
+by [setting the IPs][loadbalancer-ips] under `[loadbalancer]` in `zulip.conf`.
+
+[loadbalancer-ips]: https://zulip.readthedocs.io/en/latest/production/deployment.html#configuring-zulip-to-trust-proxies
+
 ### Manual configuration
 
 The way the environment variables configuration process described in

entrypoint.sh

@@ -133,17 +133,32 @@ nginxConfiguration() {
 }
 additionalPuppetConfiguration() {
     echo "Executing additional puppet configuration ..."
+
+    local changedPuppetConf=false
+
     if [ "$QUEUE_WORKERS_MULTIPROCESS" == "True" ] || [ "$QUEUE_WORKERS_MULTIPROCESS" == "true" ]; then
         echo "Setting queue workers to run in multiprocess mode ..."
         crudini --set /etc/zulip/zulip.conf application_server queue_workers_multiprocess true
+        changedPuppetConf=true
     elif [ "$QUEUE_WORKERS_MULTIPROCESS" == "False" ] || [ "$QUEUE_WORKERS_MULTIPROCESS" == "false" ]; then
         echo "Setting queue workers to run in multithreaded mode ..."
         crudini --set /etc/zulip/zulip.conf application_server queue_workers_multiprocess false
+        changedPuppetConf=true
     else
-        echo "No additional puppet configuration executed."
-        return 0
+        echo "No additional puppet configuration executed for queue workers."
+    fi
+
+    if [ -n "$LOADBALANCER_IPS" ]; then
+        echo "Setting IPs for load balancer"
+        crudini --set /etc/zulip/zulip.conf loadbalancer ips "${LOADBALANCER_IPS}"
+        changedPuppetConf=true
+    else
+        echo "No additional puppet configuration executed for load balancer IPs."
+    fi
+
+    if [ "$changedPuppetConf" = true ]; then
+        /home/zulip/deployments/current/scripts/zulip-puppet-apply -f
     fi
-    /home/zulip/deployments/current/scripts/zulip-puppet-apply -f
 }
 configureCerts() {
     case "$SSL_CERTIFICATE_GENERATION" in