Moved environment variables to config file

.gitignore

 .DS_Store
+config.env
 
 solrdata

config.env.template

+# This config file contains the environment variables for the application passed to PHP through Docker Compose. Copy the template file to config.env and fill in the variables.
+
+# Solr variables
+# Hostname for Solr
+SOLR_HOSTNAME=
+# Solr port, usually 8983
+SOLR_PORT=
+# Solr core
+SOLR_CORE=

docker-compose.yml

     container_name: php
     build:
       context: ./php
+    env_file:
+      - config.env
     ports:
       - '9000:9000'
     volumes:

site/public/index.php

 
 // Assemble a query string to send to Solr. This uses the Solr hostname from config.env. Solr's query syntax can be found at many sites including https://lucene.apache.org/solr/guide/6_6/the-standard-query-parser.html
 // This query retrieves only the bib identifier field for records which satisfy the search query
-$solrurl = 'http://host.docker.internal:8983/solr/epo_data/select?q.op=OR&q=*%3A*&wt=json&sort=random_' . $random . '%20asc';
+#$solrurl = 'http://host.docker.internal:8983/solr/epo_data/select?q.op=OR&q=*%3A*&wt=json&sort=random_' . $random . '%20asc';
+$solrurl = 'http://' . $_ENV["SOLR_HOSTNAME"] . ':' . $_ENV["SOLR_PORT"] . '/solr/' . $_ENV["SOLR_CORE"] . '/select?q.op=OR&q=*%3A*&wt=json&sort=random_' . $random . '%20asc';
+
 
 // Perform Curl request on the Solr API
 $ch = curl_init();