DCD-1053: Add ability to specify the Lucene index directory.

README.md

@@ -156,6 +156,11 @@ Example:
    should be writable by the user `confluence`. See note below about UID
    mappings.
 
+* `ATL_LUCENE_INDEX_DIR`
+
+  The directory where [Lucene](https://lucene.apache.org/) search indexes should
+  be stored. Defaults to `index` under the Confluence home directory.
+
 ## Database configuration
 
 It is optionally possible to configure the database from the environment,

config/confluence.cfg.xml.j2

@@ -11,6 +11,8 @@
     <property name="webwork.multipart.saveDir">${localHome}/temp</property>
     <property name="attachments.dir">${confluenceHome}/attachments</property>
 
+    <property name="lucene.index.dir">{{ atl_lucene_index_dir | default('${confluenceHome}/index') }}</property>
+
     {% if atl_jdbc_url is defined %}
       {% set databases =  {
            "mysql": ["com.mysql.jdbc.Driver", "MySQLDialect"],

tests/test_image.py

@@ -172,6 +172,15 @@ def test_confluence_xml_default(docker_cli, image):
     assert xml.findall('.//buildNumber')[0].text == "0"
     assert xml.findall('.//property[@name="hibernate.connection.url"]') == []
     assert xml.findall('.//property[@name="confluence.cluster.home"]') == []
+    assert xml.findall('.//property[@name="lucene.index.dir"]')[0].text == '${confluenceHome}/index'
+
+
+def test_confluence_lucene_index(docker_cli, image):
+    container = run_image(docker_cli, image, environment={'ATL_LUCENE_INDEX_DIR': '/some/other/dir'})
+    _jvm = wait_for_proc(container, get_bootstrap_proc(container))
+
+    xml = parse_xml(container, f'{get_app_home(container)}/confluence.cfg.xml')
+    assert xml.findall('.//property[@name="lucene.index.dir"]')[0].text == '/some/other/dir'
 
 
 def test_confluence_xml_postgres(docker_cli, image, run_user):