From 2444e197c28a4ad01efeb82c568a74ea4769ccdc Mon Sep 17 00:00:00 2001
From: Mossroy <mossroy@mossroy.fr>
Date: Sat, 25 Feb 2023 14:40:13 +0100
Subject: [PATCH] Allow to replace "app" server name in nginx by value of an
 env var

By default, nginx sends php requests to an upstream "app" server.
While keeping this default behavior, this commit allows the user
to override this server name at runtime, by setting an
APP_SERVERNAME env var to the nginx container
---
 web-nginx/Dockerfile | 12 +++++++++++-
 web-nginx/nginx.conf |  2 +-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/web-nginx/Dockerfile b/web-nginx/Dockerfile
index 50d976b..234a60f 100644
--- a/web-nginx/Dockerfile
+++ b/web-nginx/Dockerfile
@@ -2,4 +2,14 @@ FROM nginx:alpine
 
 HEALTHCHECK CMD curl --fail http://localhost/tt-rss/index.php || exit 1
 
-COPY nginx.conf /etc/nginx/nginx.conf
+COPY nginx.conf /etc/nginx/templates/nginx.conf.template
+
+# By default, nginx will send the php requests to "app" server, but this server
+# name can be overridden at runtime by passing an APP_SERVERNAME env var
+ENV APP_SERVERNAME=${APP_SERVERNAME:-app}
+
+# It's necessary to set the following NGINX_ENVSUBST_OUTPUT_DIR env var to tell
+# nginx to replace the env vars of /etc/nginx/templates/nginx.conf.template
+# and put the result in /etc/nginx/nginx.conf (instead of /etc/nginx/conf.d/nginx.conf)
+# See https://github.com/docker-library/docs/tree/master/nginx#using-environment-variables-in-nginx-configuration-new-in-119
+ENV NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx
diff --git a/web-nginx/nginx.conf b/web-nginx/nginx.conf
index 40b11f7..54a7c20 100644
--- a/web-nginx/nginx.conf
+++ b/web-nginx/nginx.conf
@@ -17,7 +17,7 @@ http {
 	index index.php;
 
 	upstream app {
-		server app:9000;
+		server ${APP_SERVERNAME}:9000;
 	}
 
 	server {