searxngRebrandZaclys/docs/admin/filtron.rst
Markus Heiser 58d5da8b57 nginx: normalize installation (docs and script)s over all distros
This is the revision of the documentation about the varous nginx installation
variants.  It also implements the nginx installation scripts for morty and
filtron.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2020-04-11 13:19:11 +02:00

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.. _searx filtron:
==========================
How to protect an instance
==========================
.. sidebar:: further reading
- :ref:`filtron.sh`
- :ref:`nginx searx site`
.. contents:: Contents
:depth: 2
:local:
:backlinks: entry
.. _filtron: https://github.com/asciimoo/filtron
Searx depends on external search services. To avoid the abuse of these services
it is advised to limit the number of requests processed by searx.
An application firewall, filtron_ solves exactly this problem. Filtron is just
a middleware between your web server (nginx, apache, ...) and searx, we describe
such infratructures in chapter: :ref:`architecture`.
filtron & go
============
.. _Go: https://golang.org/
.. _filtron README: https://github.com/asciimoo/filtron/blob/master/README.md
Filtron needs Go_ installed. If Go_ is preinstalled, filtron_ is simply
installed by ``go get`` package management (see `filtron README`_). If you use
filtron as middleware, a more isolated setup is recommended. To simplify such
an installation and the maintenance of, use our script :ref:`filtron.sh`.
.. _Sample configuration of filtron:
Sample configuration of filtron
===============================
.. sidebar:: Tooling box
- :origin:`/etc/filtron/rules.json <utils/templates/etc/filtron/rules.json>`
An example configuration can be find below. This configuration limits the access
of:
- scripts or applications (roboagent limit)
- webcrawlers (botlimit)
- IPs which send too many requests (IP limit)
- too many json, csv, etc. requests (rss/json limit)
- the same UserAgent of if too many requests (useragent limit)
.. code:: json
[
{ "name": "search request",
"filters": [
"Param:q",
"Path=^(/|/search)$"
],
"interval": "<time-interval-in-sec (int)>",
"limit": "<max-request-number-in-interval (int)>",
"subrules": [
{
"name": "roboagent limit",
"interval": "<time-interval-in-sec (int)>",
"limit": "<max-request-number-in-interval (int)>",
"filters": [
"Header:User-Agent=(curl|cURL|Wget|python-requests|Scrapy|FeedFetcher|Go-http-client)"
],
"actions": [
{ "name": "log"},
{ "name": "block",
"params": {
"message": "Rate limit exceeded"
}
}
]
},
{
"name": "botlimit",
"limit": 0,
"stop": true,
"filters": [
"Header:User-Agent=(Googlebot|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT)"
],
"actions": [
{ "name": "log"},
{ "name": "block",
"params": {
"message": "Rate limit exceeded"
}
}
]
},
{
"name": "IP limit",
"interval": "<time-interval-in-sec (int)>",
"limit": "<max-request-number-in-interval (int)>",
"stop": true,
"aggregations": [
"Header:X-Forwarded-For"
],
"actions": [
{ "name": "log"},
{ "name": "block",
"params": {
"message": "Rate limit exceeded"
}
}
]
},
{
"name": "rss/json limit",
"interval": "<time-interval-in-sec (int)>",
"limit": "<max-request-number-in-interval (int)>",
"stop": true,
"filters": [
"Param:format=(csv|json|rss)"
],
"actions": [
{ "name": "log"},
{ "name": "block",
"params": {
"message": "Rate limit exceeded"
}
}
]
},
{
"name": "useragent limit",
"interval": "<time-interval-in-sec (int)>",
"limit": "<max-request-number-in-interval (int)>",
"aggregations": [
"Header:User-Agent"
],
"actions": [
{ "name": "log"},
{ "name": "block",
"params": {
"message": "Rate limit exceeded"
}
}
]
}
]
}
]
.. _filtron route request:
Route request through filtron
=============================
.. sidebar:: further reading
- :ref:`filtron.sh overview`
- :ref:`installation nginx`
- :ref:`installation apache`
Filtron can be started using the following command:
.. code:: sh
$ filtron -rules rules.json
It listens on ``127.0.0.1:4004`` and forwards filtered requests to
``127.0.0.1:8888`` by default.
Use it along with ``nginx`` with the following example configuration.
.. code:: nginx
# https://example.org/searx
location /searx {
proxy_pass http://127.0.0.1:4004/;
proxy_set_header Host $http_host;
proxy_set_header Connection $http_connection;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Scheme $scheme;
proxy_set_header X-Script-Name /searx;
}
location /searx/static {
/usr/local/searx/searx-src/searx/static;
}
Requests are coming from port 4004 going through filtron and then forwarded to
port 8888 where a searx is being run. For a complete setup see: :ref:`nginx
searx site`.