Enable configurable server port

Dockerfile

@@ -1,4 +1,6 @@
-FROM nginx:alpine
+FROM nginx:1.25-alpine
 
-COPY default.conf /etc/nginx/conf.d/default.conf
+ENV NGINX_PORT=80
+
+COPY default.conf.template /etc/nginx/templates/default.conf.template
 COPY *.html /etc/nginx/html/

README.md

@@ -1,9 +1,14 @@
-ECS Placeholder
-===============
+# ECS Placeholder
 
 The purpose of this project is to provide a placeholder image with a `/health` HTTP endpoint for use with AWS ECS and Terraform.
 
 Since Terraform is primarily an infrastructure management tool and not an application deployment tool, coupling ECS metadata
 such as task definition files to Terraform makes for complex deployment scenarios. Often times we just want to have Terraform
-create the service and deploy new ECS task definition versions independently. Since ECS requires *some* kind of image to be
+create the service and deploy new ECS task definition versions independently. Since ECS requires _some_ kind of image to be
 referenced, this is where this image comes in.
+
+## Configuration
+
+| Environment Variable | Description                                                   | Default |
+| -------------------- | ------------------------------------------------------------- | ------- |
+| `NGINX_PORT`         | Controls the port on which the server listens for requests on | `80`    |

default.conf → default.conf.template

@@ -1,5 +1,5 @@
 server {
-    listen 80;
+    listen ${NGINX_PORT};
 
     location / {
         try_files /index.html /index.html;