Allow starting without Elasticsearch. (#171)

* Allow starting without Elasticsearch.

* Document running without Elasticsearch in the README.md.

README.md

@@ -40,6 +40,12 @@ Like this, you can add your `docker-compose.prod.yml` to a branch of your Git re
 
 * RANCHER_URL=http://RANCHER_HOST:8080 rancher-compose --env-file=.env up
 
+## Running without Elasticsearch
+
+Elasticsearch is an optional, but strongly recommended dependency for Zammad. More details can be found in the [documentation](https://docs.zammad.org/en/latest/prerequisites/software.html#elasticsearch-optional). There are however certain scenarios when running without Elasticsearch may be desired, e.g. for very small teams, for teams with limited budget or as a temporary solution for an unplanned Elasticsearch downtime or planned cluster upgrade.
+
+Elasticsearch is enabled by default in the example `docker-compose.yml` file. It is also by default required to run the "zammad-init" command. Disabling Elasticsearch is possible by setting a special environment variable: `ELASTICSEARCH_ENABLED=false` for the `zammad-init` container and removing all references to Elasticsearch everywhere else: the `zammad-elasticsearch` container, it's volume and links to it.
+
 ## Upgrading
 
 ### From =< 3.3.0-12

containers/zammad/docker-entrypoint.sh

@@ -3,6 +3,7 @@
 set -e
 
 : "${AUTOWIZARD_JSON:=''}"
+: "${ELASTICSEARCH_ENABLED:=true}"
 : "${ELASTICSEARCH_HOST:=zammad-elasticsearch}"
 : "${ELASTICSEARCH_PORT:=9200}"
 : "${ELASTICSEARCH_SCHEMA:=http}"
@@ -77,29 +78,33 @@ if [ "$1" = 'zammad-init' ]; then
 
   # es config
   echo "changing settings..."
-  bundle exec rails r "Setting.set('es_url', '${ELASTICSEARCH_SCHEMA}://${ELASTICSEARCH_HOST}:${ELASTICSEARCH_PORT}')"
+  if [ "${ELASTICSEARCH_ENABLED}" == "false" ]; then
-
+    bundle exec rails r "Setting.set('es_url', '')"
-  bundle exec rails r "Setting.set('es_index', '${ELASTICSEARCH_NAMESPACE}')"
-
-  if [ -n "${ELASTICSEARCH_USER}" ] && [ -n "${ELASTICSEARCH_PASS}" ]; then
-    bundle exec rails r "Setting.set('es_user', \"${ELASTICSEARCH_USER}\")"
-    bundle exec rails r "Setting.set('es_password', \"${ELASTICSEARCH_PASS}\")"
-  fi
-
-  until (echo > /dev/tcp/${ELASTICSEARCH_HOST}/${ELASTICSEARCH_PORT}) &> /dev/null; do
-    echo "zammad railsserver waiting for elasticsearch server to be ready..."
-    sleep 5
-  done
-
-  if [ "${ELASTICSEARCH_SSL_VERIFY}" == "false" ]; then
-    SSL_SKIP_VERIFY="-k"
   else
-    SSL_SKIP_VERIFY=""
+    bundle exec rails r "Setting.set('es_url', '${ELASTICSEARCH_SCHEMA}://${ELASTICSEARCH_HOST}:${ELASTICSEARCH_PORT}')"
-  fi
 
-  if ! curl -s ${SSL_SKIP_VERIFY} ${ELASTICSEARCH_SCHEMA}://${ELASTICSEARCH_HOST}:${ELASTICSEARCH_PORT}/_cat/indices | grep -q zammad; then
+    bundle exec rails r "Setting.set('es_index', '${ELASTICSEARCH_NAMESPACE}')"
-    echo "rebuilding es searchindex..."
+
-    bundle exec rake searchindex:rebuild
+    if [ -n "${ELASTICSEARCH_USER}" ] && [ -n "${ELASTICSEARCH_PASS}" ]; then
+      bundle exec rails r "Setting.set('es_user', \"${ELASTICSEARCH_USER}\")"
+      bundle exec rails r "Setting.set('es_password', \"${ELASTICSEARCH_PASS}\")"
+    fi
+
+    until (echo > /dev/tcp/${ELASTICSEARCH_HOST}/${ELASTICSEARCH_PORT}) &> /dev/null; do
+      echo "zammad railsserver waiting for elasticsearch server to be ready..."
+      sleep 5
+    done
+
+    if [ "${ELASTICSEARCH_SSL_VERIFY}" == "false" ]; then
+      SSL_SKIP_VERIFY="-k"
+    else
+      SSL_SKIP_VERIFY=""
+    fi
+
+    if ! curl -s ${SSL_SKIP_VERIFY} ${ELASTICSEARCH_SCHEMA}://${ELASTICSEARCH_HOST}:${ELASTICSEARCH_PORT}/_cat/indices | grep -q zammad; then
+      echo "rebuilding es searchindex..."
+      bundle exec rake searchindex:rebuild
+    fi
   fi
 
   # chown everything to zammad user