Update elasticsearch

- Build our own elasticsearch image based on 6.8.6 which includes
configuration files for german decompounder from https://github.com/uschindler/german-decompounder

- move elastichq to separate service and use the official image instead of including it as plugin in the elasticsearch image

- Adjust compounder filter config in papers to use the included hyphenation_decompounder.
See https://www.elastic.co/guide/en/elasticsearch/reference/6.8/analysis-compound-word-tokenfilter.html

- Remove obsolete "string" type in the mapping of papers, and replace it
with "text" or "keywords" accordingly. See https://www.elastic.co/blog/strings-are-dead-long-live-strings

Gemfile

@@ -31,8 +31,8 @@ gem 'omniauth'
 gem 'omniauth-browserid'
 
 gem 'elasticsearch', '~> 6'
-gem 'elasticsearch-model'
-gem 'elasticsearch-rails'
+gem 'elasticsearch-model', '~> 6'
+gem 'elasticsearch-rails', '~> 6'
 gem 'elasticsearch-dsl'
 
 gem 'leaflet-rails'

Gemfile.lock

@@ -79,11 +79,11 @@ GEM
     elasticsearch-api (6.0.2)
       multi_json
     elasticsearch-dsl (0.1.5)
-    elasticsearch-model (5.0.0)
+    elasticsearch-model (6.1.0)
       activesupport (> 3)
       elasticsearch (> 1)
       hashie
-    elasticsearch-rails (5.0.2)
+    elasticsearch-rails (6.1.0)
     elasticsearch-transport (6.0.2)
       faraday
       multi_json
@@ -287,8 +287,8 @@ DEPENDENCIES
   database_cleaner
   elasticsearch (~> 6)
   elasticsearch-dsl
-  elasticsearch-model
-  elasticsearch-rails
+  elasticsearch-model (~> 6)
+  elasticsearch-rails (~> 6)
   factory_bot_rails
   faker
   foundation-rails (~> 5.5)

app/models/paper.rb

@@ -22,42 +22,46 @@ class Paper < ActiveRecord::Base
   index_name ['srm', Rails.env, self.base_class.to_s.pluralize.underscore].join('_')
 
   settings index: {
-	  number_of_shards: 1,
-	  analysis: {
-		filter: {
-		  german_stop: {
-		    type: "stop",
-		    stopwords: "_german_"
-          }, 
-		  german_stemmer: {
-		    type: "stemmer",
-		    language: "light_german"
-          },
-		  decomp: {
-		    type: "decompound"
-          }
+    number_of_shards: 1,
+    analysis: {
+      filter: {
+        german_stop: {
+          type: "stop",
+          stopwords: "_german_"
         },
-		analyzer: {
-		  german: {
-		    tokenizer: "standard",
-		    filter: [
-		      "lowercase",
-		      "german_stop",
-		      "german_normalization",
-		      "german_stemmer",
-		      "decomp"
-		    ]
-          }
+        german_stemmer: {
+          type: "stemmer",
+          language: "light_german"
+        },
+        german_decompounder: {
+          type: "hyphenation_decompounder",
+          word_list_path: "analysis/dictionary-de.txt",
+          hyphenation_patterns_path: "analysis/de_DR.xml",
+          only_longest_match: true,
+          min_subword_size: 4
+        },
+      },
+      analyzer: {
+        german: {
+          tokenizer: "standard",
+          filter: [
+            "lowercase",
+            "german_stop",
+              "german_decompounder",
+            "german_normalization",
+            "german_stemmer"
+          ]
         }
       }
+    }
     } do mappings dynamic: false do
-      indexes :name, type: :string, analyzer: "german"
-      indexes :content, type: :string, analyzer: "german"
-      indexes :resolution, type: :string, analyzer: "german"
-      indexes :reference, type: :string, index: :not_analyzed
-      indexes :paper_type, type: :string, index: :not_analyzed
-      indexes :published_at, type: :date, index: :not_analyzed
-      indexes :originator, type: :string, index: :not_analyzed
+      indexes :name, type: :text, analyzer: "german"
+      indexes :content, type: :text, analyzer: "german"
+      indexes :resolution, type: :text, analyzer: "german"
+      indexes :reference, type: :keyword, index: true
+      indexes :paper_type, type: :keyword, index: true
+      indexes :published_at, type: :date, index: true
+      indexes :originator, type: :keyword, index: true
     end
   end
 

docker-compose.yml

@@ -1,22 +1,28 @@
-web:
-  build: .
-  volumes:
-    - .:/app
-  ports:
-    - "3000:3000"
-  links:
-    - elasticsearch
-  environment:
-    ELASTICSEARCH_URL: 'http://elasticsearch:9200'
-elasticsearch:
-  image: elasticsearch:5.4.3
-  command:
-    - sh
-    - -c
-    - "./bin/elasticsearch-plugin install http://xbib.org/repository/org/xbib/elasticsearch/plugin/elasticsearch-analysis-decompound/5.4.3.0/elasticsearch-analysis-decompound-5.4.3.0-plugin.zip;
-      ./bin/elasticsearch-plugin install https://github.com/royrusso/elasticsearch-HQ/zipball/master;
-       /docker-entrypoint.sh elasticsearch"
-  ports:
-    - "9200:9200"
-  volumes:
-    - .:/apps
+version: "3.7"
+volumes:
+  elasticsearch:
+services:
+  web:
+    build: .
+    volumes:
+      - .:/app
+    ports:
+      - "3000:3000"
+    links:
+      - elasticsearch
+    environment:
+      ELASTICSEARCH_URL: 'http://elasticsearch:9200'
+  elasticsearch:
+    build: ./docker/elasticsearch
+    environment:
+      - discovery.type=single-node
+    ports:
+      - "9200:9200"
+    volumes:
+      - elasticsearch:/usr/share/elasticsearch/data
+  elastichq:
+    image: elastichq/elasticsearch-hq
+    ports:
+      - "5000:5000"
+    links:
+      - elasticsearch

docker/elasticsearch/Dockerfile

@@ -0,0 +1,8 @@
+FROM elasticsearch:6.8.6
+
+RUN \
+  mkdir -p /usr/share/elasticsearch/config/analysis && \
+  pushd /usr/share/elasticsearch/config/analysis && \
+  curl -sSLO https://github.com/uschindler/german-decompounder/raw/master/de_DR.xml && \
+  curl -sSLO https://github.com/uschindler/german-decompounder/raw/master/dictionary-de.txt && \
+  popd