Support for env var replacement

1.8/Dockerfile

@@ -48,6 +48,7 @@ VOLUME ["/var/opt/rh/rh-nginx18/log/nginx/"]
 
 ENV BASH_ENV=/opt/app-root/etc/scl_enable \
     ENV=/opt/app-root/etc/scl_enable \
+    PRE_RUN_SCRIPT=/opt/app-root/etc/init_script \
     PROMPT_COMMAND=". /opt/app-root/etc/scl_enable"
 
 CMD $STI_SCRIPTS_PATH/usage

1.8/Dockerfile.rhel7

@@ -56,6 +56,7 @@ VOLUME ["/var/opt/rh/rh-nginx18/log/nginx/"]
 
 ENV BASH_ENV=/opt/app-root/etc/scl_enable \
     ENV=/opt/app-root/etc/scl_enable \
+    PRE_RUN_SCRIPT=/opt/app-root/etc/init_script \
     PROMPT_COMMAND=". /opt/app-root/etc/scl_enable"
 
 CMD $STI_SCRIPTS_PATH/usage

1.8/README.md

@@ -16,8 +16,10 @@ S2I build folder structure:
 
 |    Folder name         |    Description                            |
 | :--------------------- | ----------------------------------------- |
-|  ./nginx-cfg/*.conf    | Should contain all nginx configuration we want to include into image |
+|  ./nginx-cfg/*.conf    | Should contain nginx configuration files that should be included into image |
 |  ./                    | Should contain nginx application source code                         |
+|  ./bin/init_script     | Script that would be executed before launching nginx process. Can be used to replace values in configuration.|
+
 
 Configuration
 -------------

1.8/contrib/etc/init_script

@@ -0,0 +1,24 @@
+## Placeholder for script that would be executed before running container
+## To replace this file you should create ./bin/init_script in your s2i context folder. See: `--context-dir` option.
+
+## This file can be used to inject environment variables into the configuration files
+
+## Setup default DNS_SERVER for proxy requests
+setup_dns_env_var() {
+      if [ -z "$DNS_SERVER" ]; then
+            export DNS_SERVER=`cat /etc/resolv.conf | grep "nameserver" | awk '{print $2}' | tr '\n' ' '`
+            echo "Using system dns server ${DNS_SERVER}"
+      else
+            echo "Using user defined dns server: ${DNS_SERVER}"
+      fi  
+}
+
+## Inject environment variables
+inject_env_vars() {
+      ## Replace only specified environment variables in specified file.
+      envsubst '${DNS_SERVER}
+                ${LOG_LEVEL}' < "${NGINX_CONFIGURATION_PATH}/$1" > "${NGINX_CONFIGURATION_PATH}/$1"
+}
+
+# setup_dns_env_var
+# inject_env_vars "default.conf"

1.8/s2i/bin/assemble

@@ -9,9 +9,17 @@ if [ -d ./nginx-cfg ]; then
   echo "---> Copying nginx configuration files..."
   if [ "$(ls -A ./nginx-cfg/*.conf)" ]; then
     cp -v ./nginx-cfg/*.conf "${NGINX_CONFIGURATION_PATH}"
+    chmod -Rf 777 ${NGINX_CONFIGURATION_PATH}
     rm -rf ./nginx-cfg
   fi
 fi
 
+if [ -f ./bin/init_script ]; then
+  echo "---> Copying nginx init script..."
+  cp -vf ./bin/init_script $PRE_RUN_SCRIPT
+  chmod +x $PRE_RUN_SCRIPT
+  rm -rf ./bin
+fi
+
 # Fix source directory permissions
 fix-permissions ./

1.8/s2i/bin/run

@@ -1,6 +1,7 @@
 #!/bin/bash
 
 source /opt/app-root/etc/generate_container_user
+source $PRE_RUN_SCRIPT
 
 set -e
 

1.8/test/test-app/bin/init_script

@@ -0,0 +1,19 @@
+setup_dns_env_var() {
+      if [ -z "$DNS_SERVER" ]; then
+            export DNS_SERVER=`cat /etc/resolv.conf | grep "nameserver" | awk '{print $2}' | tr '\n' ' '`
+            echo "Using system dns server ${DNS_SERVER}"
+      else
+            echo "Using user defined dns server: ${DNS_SERVER}"
+      fi  
+}
+
+inject_env_vars() {
+      ## Replace only specified environment variables in specified file.
+      envsubst '${DNS_SERVER}
+                ${INDEX_FILE}' < "${NGINX_CONFIGURATION_PATH}/$1" > "${NGINX_CONFIGURATION_PATH}/$1"
+}
+
+export INDEX_FILE=index2.html
+setup_dns_env_var
+inject_env_vars "default.conf"
+

1.8/test/test-app/nginx-cfg/default.conf

@@ -2,5 +2,7 @@ server {
 	listen       8080 default_server;
 	server_name  localhost2;
 	root         /opt/app-root/src;
-	index        index2.html;
+	index        ${INDEX_FILE};
+	resolver ${DNS_SERVER};
+
 }