[FEATURE] Introduce TYPO3_SOLR_ENABLED_CORES docker env variable

This adds a startup script which disables all unneeded cores.

Usage:

`docker run -e 'TYPO3_SOLR_ENABLED_CORES=english german' -it typo3solr/ext-solr`

This enables only the english and german core (core_en, core_de) during startup.

If the env variable is not set, then all cores are enabled (= default behaviour).

The additional cores can be enabled afterwards by adding them to the TYPO3_SOLR_ENABLED_CORES env. variable.

Fixes: #3502

Build/Test/cibuild_docker.sh

@@ -153,6 +153,14 @@ isCoreAvailable ()
   return 0;
 }
 
+isCoreUnavailable ()
+{
+  if ! isCoreAvailable $1; then
+    return 0;
+  fi
+  return 1;
+}
+
 pingCore ()
 {
   # shellcheck disable=SC2015
@@ -262,6 +270,48 @@ assertNecessaryPathsAreOwnedBySolr ()
   isPathOwnedBySolr "${paths[@]}" || { echo -e "${RED}"'\nThe image has files, which are not owned by solr(8983) user.\n Please fix this issue.'"${NC}"; cleanUp; exit 1; }
 }
 
+assertCoresAreSwitchableViaEnvVar ()
+{
+  echo -e "\nCheck all cores are disabled except desired by \$TYPO3_SOLR_ENABLED_CORES env:"
+  echo -n "  stop container $LOCAL_CONTAINER_NAME" prettyPrintOrExitOnError $? "$(docker stop "$LOCAL_CONTAINER_NAME" 2>&1)"
+
+  echo -n "Starting container"
+  prettyPrintOrExitOnError $? "$(docker run --env TYPO3_SOLR_ENABLED_CORES='german english danish' --name="$LOCAL_CONTAINER_NAME" -d -p 127.0.0.1:8998:8983 -v "$LOCAL_VOLUME_NAME":"$DEFAULT_IMAGE_VOLUME_EXPORT_PATH" "$LOCAL_IMAGE_NAME" 2>&1)"
+
+  ENABLED_CORES=(
+    "core_de"
+    "core_en"
+    "core_da"
+  )
+
+  SOME_DISABLED_CORES=(
+    "core_fi"
+    "core_fr"
+    "core_gl"
+    "core_el"
+    "core_hi"
+    "core_hu"
+    "core_id"
+    "core_it"
+    "core_ja"
+  )
+
+  echo -e "\nCheck enabled cores are available:"
+  for core in "${ENABLED_CORES[@]}"
+  do
+    echo -n "  $core is enabled"
+    prettyPrintOrExitOnError $? "$(isCoreAvailable "$core" 2>&1)"
+  done
+
+  echo -e "\nCheck few other cores are really disabled:"
+  for core in "${SOME_DISABLED_CORES[@]}"
+  do
+    echo -n "  $core is disabled"
+    prettyPrintOrExitOnError $? "$(isCoreUnavailable "$core" 2>&1)"
+  done
+
+}
+
 ### run the tests
 
 assertDockerVersionIsGtOrEq193
@@ -276,6 +326,8 @@ assertAllCoresAreQueriable
 assertDataPathIsCreatedByApacheSolr
 assertNecessaryPathsAreOwnedBySolr
 
+assertCoresAreSwitchableViaEnvVar
+
 
 echo -e "${GREEN}"'\nAll checks passed successfully!\n'"${NC}"
 

Docker/SolrServer/Dockerfile

@@ -4,6 +4,7 @@ ENV TERM linux
 
 USER root
 RUN rm -fR /opt/solr/server/solr/*
+COPY Docker/SolrServer/docker-entrypoint-initdb.d/ /docker-entrypoint-initdb.d
 USER solr
 
 COPY --chown=solr:solr Resources/Private/Solr/ /var/solr/data

Docker/SolrServer/docker-entrypoint-initdb.d/disable-cores.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+shopt -s extglob
+
+if [ -n "${TYPO3_SOLR_ENABLED_CORES}" ]
+then
+  for CORE_TO_DISABLE in /var/solr/data/cores/*/core.properties
+  do
+    mv "${CORE_TO_DISABLE}" "${CORE_TO_DISABLE}_disabled";
+  done
+
+  for CORE_to_ENABLE in ${TYPO3_SOLR_ENABLED_CORES}
+  do
+    echo "Enable core ${CORE_to_ENABLE}"
+    mv "/var/solr/data/cores/${CORE_to_ENABLE}/core.properties_disabled" "/var/solr/data/cores/${CORE_to_ENABLE}/core.properties"
+  done
+fi

Documentation/Appendix/DockerTweaks.rst

@@ -0,0 +1,21 @@
+.. include:: /Includes.rst.txt
+
+
+.. _appendix-docker-tweaks:
+
+Appendix - Docker Tweaks
+========================
+
+Beside of original Apache Solr Docker image, on which is our image based on we provide some tweaks to make our and your work simpler.
+
+Disable unnecessary cores on container start
+--------------------------------------------
+
+By defining env ``TYPO3_SOLR_ENABLED_CORES`` with a space separated list of languages/cores to enable, only those cores will be initialized on start-up.
+This allows to save memory usage of Apache Solr server instance.
+
+Usage:
+
+.. code-block::  bash
+
+    docker run -e 'TYPO3_SOLR_ENABLED_CORES=english german' -it typo3solr/ext-solr

Documentation/GettingStarted/Solr.rst

@@ -148,6 +148,11 @@ The following example shows how you can run our configuration with the official
     sudo chown -R 8983:8983 ~/mysolr
     docker run -d -p 8983:8983 -v ~/mysolr:/var/solr/data solr:8.5
 
+Advanced settings and tweaks
+----------------------------
+
+For more settings and tweak possibilities for our Docker image, please refer to the :ref:`appendix-docker-tweaks`.
+
 Other Setup
 -----------