[docs] revision of the blog article about local search engines

The blog article 'Query your local search engines' has been renamed 'Local
Search Engines', revised and moved into admin's chapter 'Engine & Settings'.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

2 files changed, 137 insertions, 2 deletions

diff --git a/docs/admin/engines/index.rst b/docs/admin/engines/index.rst
index 51707b792..80f4120a5 100644
--- a/docs/admin/engines/index.rst
+++ b/docs/admin/engines/index.rst
@@ -17,7 +17,6 @@ Engines & Settings
    private-engines
    recoll
    sql-engines
+   search-indexer-engines
    command-line-engines
    searx.engines.xpath
-
-
diff --git a/docs/admin/engines/search-indexer-engines.rst b/docs/admin/engines/search-indexer-engines.rst
new file mode 100644
index 000000000..8d7c10d67
--- /dev/null
+++ b/docs/admin/engines/search-indexer-engines.rst
@@ -0,0 +1,136 @@
+====================
+Local Search Engines
+====================
+
+.. sidebar:: further read
+
+   - `Comparison to alternatives
+     <https://docs.meilisearch.com/learn/what_is_meilisearch/comparison_to_alternatives.html>`_
+
+Administrators might find themselves wanting to integrate locally running search
+engines.  The following ones are supported for now:
+
+* `Elasticsearch`_
+* `Meilisearch`_
+* `Solr`_
+
+Each search engine is powerful, capable of full-text search.  All of the engines
+above are added to ``settings.yml`` just commented out, as you have to
+``base_url`` for all them.
+
+Please note that if you are not using HTTPS to access these engines, you have to enable
+HTTP requests by setting ``enable_http`` to ``True``.
+
+Futhermore, if you do not want to expose these engines on a public instance, you
+can still add them and limit the access by setting ``tokens`` as described in
+section :ref:`private engines`.
+
+.. _engine meilisearch:
+
+MeiliSearch
+===========
+
+.. sidebar:: info
+
+   - :origin:`meilisearch.py <searx/engines/meilisearch.py>`
+   - `MeiliSearch <https://www.meilisearch.com>`_
+   - `MeiliSearch Documentation <https://docs.meilisearch.com/>`_
+   - `Install MeiliSearch
+     <https://docs.meilisearch.com/learn/getting_started/installation.html>`_
+
+MeiliSearch_ is aimed at individuals and small companies.  It is designed for
+small-scale (less than 10 million documents) data collections.  E.g. it is great
+for storing web pages you have visited and searching in the contents later.
+
+The engine supports faceted search, so you can search in a subset of documents
+of the collection.  Furthermore, you can search in MeiliSearch_ instances that
+require authentication by setting ``auth_token``.
+
+Here is a simple example to query a Meilisearch instance:
+
+.. code:: yaml
+
+  - name: meilisearch
+    engine: meilisearch
+    shortcut: mes
+    base_url: http://localhost:7700
+    index: my-index
+    enable_http: true
+
+
+.. _engine elasticsearch:
+
+Elasticsearch
+=============
+
+.. sidebar:: info
+
+   - :origin:`elasticsearch.py <searx/engines/elasticsearch.py>`
+   - `Elasticsearch <https://www.elastic.co/elasticsearch/>`_
+   - `Elasticsearch Guide
+     <https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html>`_
+   - `Install Elasticsearch
+     <https://www.elastic.co/guide/en/elasticsearch/reference/current/install-elasticsearch.html>`_
+
+Elasticsearch_ supports numerous ways to query the data it is storing.  At the
+moment the engine supports the most popular search methods (``query_type``):
+
+- ``match``,
+- ``simple_query_string``,
+- ``term`` and
+- ``terms``.
+
+If none of the methods fit your use case, you can select ``custom`` query type
+and provide the JSON payload to submit to Elasticsearch in
+``custom_query_json``.
+
+The following is an example configuration for an Elasticsearch_ instance with
+authentication configured to read from ``my-index`` index.
+
+.. code:: yaml
+
+  - name: elasticsearch
+    shortcut: es
+    engine: elasticsearch
+    base_url: http://localhost:9200
+    username: elastic
+    password: changeme
+    index: my-index
+    query_type: match
+    # custom_query_json: '{ ... }'
+    enable_http: true
+
+.. _engine solr:
+
+Solr
+====
+
+.. sidebar:: info
+
+   - :origin:`solr.py <searx/engines/solr.py>`
+   - `Solr <https://solr.apache.org>`_
+   - `Solr Resources <https://solr.apache.org/resources.html>`_
+   - `Install Solr <https://solr.apache.org/guide/installing-solr.html>`_
+
+Solr_ is a popular search engine based on Lucene, just like Elasticsearch_.  But
+instead of searching in indices, you can search in collections.
+
+This is an example configuration for searching in the collection
+``my-collection`` and get the results in ascending order.
+
+.. code:: yaml
+
+  - name: solr
+    engine: solr
+    shortcut: slr
+    base_url: http://localhost:8983
+    collection: my-collection
+    sort: asc
+    enable_http: true
+
+
+Acknowledgment
+==============
+
+This development was sponsored by `Search and Discovery Fund
+<https://nlnet.nl/discovery>`_ of `NLnet Foundation <https://nlnet.nl/>`_.