Install Nextcloud-Elasticsearch

This installation guide ist tested with Ubuntu 16.04 and Nextcloud 13.

We will install Elasticsearch as a service, install the Elasticsearch Ingest-Attachment Plugin for indexing office files like PDF, XLS (and more, about 1.000 different file types), install the Nextcloud Full Text Search App of the Nextcloud App store, install the ReadonlyREST Elasticsearch Plugin to permit/forbid accessing the index and finally install the live index as a service.

Prerequisites

If not already installed, install Java 8 and apt-transport-https

apt install apt-transport-https

Check Java Version

java -version
java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)

Install Elasticsearch

curl -L -O https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.2.4.deb
dpkg -i elasticsearch-6.2.4.deb

Start Elasticsearch

/etc/init.d/elasticsearch start

Test Elasticsearch

curl http://127.0.0.1:9200
{
 "name" : "gbqbjp7",
 "cluster_name" : "elasticsearch",
 "cluster_uuid" : "cP8B2VFDSqKjM_RmJF4CBQ",
 "version" : {
 "number" : "6.2.4",
 "build_hash" : "ccec39f",
 "build_date" : "2018-04-12T20:37:28.497551Z",
 "build_snapshot" : false,
 "lucene_version" : "7.2.1",
 "minimum_wire_compatibility_version" : "5.6.0",
 "minimum_index_compatibility_version" : "5.0.0"
 },
 "tagline" : "You Know, for Search"
}

Enable Elasticsearch Service

systemctl daemon-reload
systemctl enable elasticsearch
Synchronizing state of elasticsearch.service with SysV init with /lib/systemd/systemd-sysv-install...
Executing /lib/systemd/systemd-sysv-install enable elasticsearch
Created symlink from /etc/systemd/system/multi-user.target.wants/elasticsearch.service to /usr/lib/systemd/system/elasticsearch.service.
systemctl start elasticsearch
service elasticsearch restart

Install Elasticsearch Ingest-Attachment Plugin

The ingest attachment plugin lets Elasticsearch extract file attachments in common formats (such as PPT, XLS, and PDF) by using the Apache text extraction library Tika.

/usr/share/elasticsearch/bin/elasticsearch-plugin install ingest-attachment

Elasticsearch Config File

vi /etc/elasticsearch/elasticsearch.yml
network.host: 127.0.0.1
http.port: 9200

Elasticsearch Log Files

cd /var/log/elasticsearch

Increase Java heap size

By default, Elasticsearch tells the JVM to use a heap with a minimum and maximum size of 1 GB.

vi /etc/elasticsearch/jvm.options
# Heap is 1 GB (default)
#-Xms1g
#-Xmx1g

# Heap is 2 GB
-Xms2g
-Xmx2g

Add Elasticsearch Ports to Services

Port 9200 is for REST, port 9300 is for nodes communication.

vi /etc/services
elastic-rest 9200/tcp     # Nextcloud
elastic-node 9300/tcp     # Nextcloud
netstat -pat | grep elastic
tcp6   0   0   localhost:elastic-rest   [::]:*   LISTEN   17186/java
tcp6   0   0   localhost:elastic-node   [::]:*   LISTEN   17186/java

Now all prerequisites are installed, continue with the installation of the 3 full text search apps of the Nextcloud store.

Install Nextcloud Apps

Configure Full Text Search App

Navigate to Admin Console | Full text search and configure the Search platform, Address of Servlet and Name of your index (should be in lower case).

Your full text search engine is now configured and ready for a first run.

First Index

Run the command

sudo -u www-data php occ fulltextsearch:index

Install ReadonlyREST Elasticsearch Plugin

ReadonlyREST is a plugin that adds encryption, authentication, authorization and access control capabilities to Elasticsearch embedded REST API.

Got to the official download page readonlyrest.com/download and send yourself a mail with the download link.

After downloading, cd to /usr/share/elasticsearch and install the plugin.

cd /usr/share/elasticsearch
bin/elasticsearch-plugin install file:///download-folder/readonlyrest-1.16.19_es6.2.4.zip
-> Downloading file:///download-folder/readonlyrest-1.16.19_es6.2.4.zip
[=================================================] 100%??
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: plugin requires additional permissions @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
* java.io.FilePermission << ALL FILES >> read
* java.lang.RuntimePermission accessDeclaredMembers
* java.lang.RuntimePermission getClassLoader
* java.lang.reflect.ReflectPermission suppressAccessChecks
* java.net.SocketPermission * connect,accept,resolve
* java.security.SecurityPermission getProperty.ssl.KeyManagerFactory.algorithm
* java.util.PropertyPermission * read,write
See http://docs.oracle.com/javase/8/docs/technotes/guides/security/permissions.html
for descriptions of what these permissions allow and the associated risks.

Continue with installation? [y/N]y
-> Installed readonlyrest

Configure ReadonlyREST

Create a new file in /etc/elasticsearch and paste a snippet that you found in the documentation page: github.com/sscarduzio/elasticsearch-readonlyrest-plugin.

vi /etc/elasticsearch/readonlyrest.yml
readonlyrest:
    access_control_rules:

    - name: Accept requests from my_cloud on my_index
      groups: ["my_cloud"]
      indices: ["my_index"]

    - name: Accept requests from cloud2 on another_index
      groups: ["cloud2"]
      indices: ["another_index"]

    users:

    - username: username
      auth_key: username:password
      groups: ["my_cloud"]

    - username: test
      auth_key_sha1: a94a8fe5ccb19ba61c4c0873d391e987982fbbd3
      groups: ["cloud2"]

Replace username with the real username and password with a real password.

Note the indents – they are mandatory in YAML. Otherwise you’ll get the error

Could not find required attribute 'readonlyrest' in file pidfile:/var/run/elasticsearch/elasticsearch.pid,cluster:{name=elasticsearch},node:{name=fbhajo9},path:{data=[/var/lib/elasticsearch], logs=/var/log/elasticsearch, home=/usr/share/elasticsearch},client:{type=node},http:{port=9200},network:{host=127.0.0.1}

Generate the password with

pwgen -a -y 16

and fill in the username and password in the admin console of Nextcloud at Address of Servlet, like

http://username:password@localhost:9200

Restart Elasticsearch with service elasticsearch restart and you are done.

Live Index Service

To continuously index the files, the command

php occ fulltextsearch:live -vvv

is necessary. This can easily be achived by installing it as a service.

Create a new file

vi /etc/systemd/system/nextcloud-fulltext-elasticsearch-worker.service
[Unit]
Description=Elasticsearch Worker for Nextcloud Fulltext Search
After=network.target

[Service]
User=www-data
Group=www-data
WorkingDirectory=/var/www/nextcloud
ExecStart=/usr/bin/php /var/www/nextcloud/occ fulltextsearch:live
Nice=19
Restart=always

[Install]
WantedBy=multi-user.target

Adjust User, Group, WorkingDirectory and the path to your occ file.

Enable Service

systemctl enable nextcloud-fulltext-elasticsearch-worker.service
Created symlink from /etc/systemd/system/multi-user.target.wants/nextcloud-fulltext-elasticsearch-worker.service to /etc/systemd/system/nextcloud-fulltext-elasticsearch-worker.service.

Start Service

service nextcloud-fulltext-elasticsearch-worker start
ps ax | grep fulltextsearch:live
5416 ? SNs 0:00 /usr/bin/php /var/www/nextcloud/occ fulltextsearch:live

Congratulations!

Your full text search engine for Nextcloud is now configured, up and running.

Increase number of search result list

vi /var/www/nextcloud/apps/fulltextsearch/js/navigate.js
410gg
var request = {
    providers: providers,
    options: options,
    search: search,
    page: curr.page,
    size: 20
};