Add support for fast searching via Solr

This installs and configures Solr running under Tomcat, and configures
Dovecot to use the dovecot-solr plugin for all search and indexing.

This dramatically improves search performance on large mailboxes.

setup/solr.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+# IMAP search with lucene via solr
+# --------------------------------
+#
+# By default dovecot uses its own Squat search index that has awful performance
+# on large mailboxes. Dovecot 2.1+ has support for using Lucene internally but
+# this didn't make it into the Ubuntu packages, so we use Solr instead to run
+# Lucene for us.
+#
+# Solr runs as a tomcat process. The dovecot solr plugin talks to solr via its
+# HTTP interface, causing mail to be indexed when searches occur, and getting
+# results back.
+
+source setup/functions.sh # load our functions
+source /etc/mailinabox.conf # load global vars
+
+# Install packages and basic configuation
+# ---------------------------------------
+
+# Install packages
+apt_install solr-tomcat dovecot-solr
+
+# Solr requires a schema to tell it how to index data, this is provided by dovecot
+wget http://hg.dovecot.org/dovecot-2.2/raw-file/e99cd21e1f92/doc/solr-schema.xml \
+    -O /etc/solr/conf/schema.xml
+
+# Update the dovecot plugin configuration
+#
+# Break-imap-search makes search work the way users expect, rather than the way
+# the IMAP specification expects
+tools/editconf.py /etc/dovecot/conf.d/10-mail.conf \
+        mail_plugins="$mail_plugins fts fts_solr"
+
+cat > /etc/dovecot/conf.d/90-plugin.conf << EOF;
+plugin {
+  fts = solr
+  fts_solr = break-imap-search url=http://127.0.0.1:8080/solr/
+}
+EOF
+
+# PERMISSIONS
+
+# Ensure configuration files are owned by dovecot and not world readable.
+chown -R mail:dovecot /etc/dovecot
+chmod -R o-rwx /etc/dovecot
+
+# Restart services to reload solr schema & dovecot plugins
+restart_service tomcat6
+restart_service dovecot

setup/start.sh

@@ -120,6 +120,7 @@ source setup/mail-dovecot.sh
 source setup/mail-users.sh
 source setup/dkim.sh
 source setup/spamassassin.sh
+source setup/solr.sh
 source setup/web.sh
 source setup/webmail.sh
 source setup/owncloud.sh