Update documentation for new Python frontend

docs/CMakeLists.txt

@@ -11,6 +11,7 @@ set (DOC_SOURCES
      develop
      api
      customize
+     library
      index.md
      extra.css
      styles.css
@@ -25,10 +26,10 @@ endforeach()
 ADD_CUSTOM_TARGET(doc
    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/bash2md.sh ${PROJECT_SOURCE_DIR}/vagrant/Install-on-Ubuntu-20.sh ${CMAKE_CURRENT_BINARY_DIR}/appendix/Install-on-Ubuntu-20.md
    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/bash2md.sh ${PROJECT_SOURCE_DIR}/vagrant/Install-on-Ubuntu-22.sh ${CMAKE_CURRENT_BINARY_DIR}/appendix/Install-on-Ubuntu-22.md
-   COMMAND PYTHONPATH=${PROJECT_SOURCE_DIR} mkdocs build -d ${CMAKE_CURRENT_BINARY_DIR}/../site-html -f ${CMAKE_CURRENT_BINARY_DIR}/../mkdocs.yml
+   COMMAND mkdocs build -d ${CMAKE_CURRENT_BINARY_DIR}/../site-html -f ${CMAKE_CURRENT_BINARY_DIR}/../mkdocs.yml
 )
 
 ADD_CUSTOM_TARGET(serve-doc
-    COMMAND PYTHONPATH=${PROJECT_SOURCE_DIR} mkdocs serve
-    WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
+    COMMAND mkdocs serve -f ${CMAKE_CURRENT_BINARY_DIR}/../mkdocs.yml
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
 )

docs/admin/Deployment.md → docs/admin/Deployment-PHP.md

@@ -1,4 +1,4 @@
-# Deploying Nominatim
+# Deploying Nominatim using the PHP frontend
 
 The Nominatim API is implemented as a PHP application. The `website/` directory
 in the project directory contains the configured website. You can serve this
@@ -13,8 +13,8 @@ to run a web service. Please refer to the documentation of
 for background information on configuring the services.
 
 !!! Note
-    Throughout this page, we assume that your Nominatim project directory is
-    located in `/srv/nominatim-project` and that you have installed Nominatim
+    Throughout this page, we assume your Nominatim project directory is
+    located in `/srv/nominatim-project` and you have installed Nominatim
     using the default installation prefix `/usr/local`. If you have put it
     somewhere else, you need to adjust the commands and configuration
     accordingly.

docs/admin/Deployment-Python.md

@@ -0,0 +1,122 @@
+# Deploying the Nominatim Python frontend
+
+The Nominatim can be run as a Python-based 
+[ASGI web application](https://asgi.readthedocs.io/en/latest/). You have the
+choice between [Falcon](https://falcon.readthedocs.io/en/stable/)
+and [Starlette](https://www.starlette.io/) as the ASGI framework.
+
+This section gives a quick overview on how to configure Nginx to serve
+Nominatim. Please refer to the documentation of
+[Nginx](https://nginx.org/en/docs/) for background information on how
+to configure it.
+
+!!! Note
+    Throughout this page, we assume your Nominatim project directory is
+    located in `/srv/nominatim-project` and you have installed Nominatim
+    using the default installation prefix `/usr/local`. If you have put it
+    somewhere else, you need to adjust the commands and configuration
+    accordingly.
+
+    We further assume that your web server runs as user `www-data`. Older
+    versions of CentOS may still use the user name `apache`. You also need
+    to adapt the instructions in this case.
+
+### Installing the required packages
+
+The recommended way to deploy a Python ASGI application is to run
+the ASGI runner (uvicorn)[https://uvicorn.org/]
+together with (gunicorn)[https://gunicorn.org/] HTTP server. We use
+Falcon here as the web framework.
+
+Create a virtual environment for the Python packages and install the necessary
+dependencies:
+
+``` sh
+sudo apt install virtualenv
+virtualenv /srv/nominatim-venv
+/srv/nominatim-venv/bin/pip install SQLAlchemy PyICU psycopg[binary]\
+   psycopg2-binary python-dotenv PyYAML falcon uvicorn gunicorn
+```
+
+### Setting up Nominatim as a systemd job
+
+Next you need to set up the service that runs the Nominatim frontend. This is
+easiest done with a systemd job.
+
+Create the following file `/etc/systemd/system/nominatim.service`:
+
+``` systemd
+[Unit]
+Description=Nominatim running as a gunicorn application
+After=network.target
+Requires=nominatim.socket
+
+[Service]
+Type=simple
+Environment="PYTHONPATH=/usr/local/lib/nominatim/lib-python/"
+User=www-data
+Group=www-data
+WorkingDirectory=/srv/nominatim-project
+ExecStart=/srv/nominatim-venv/bin/gunicorn -b unix:/run/nominatim.sock -w 4 -k uvicorn.workers.UvicornWorker nominatim.server.falcon.server:run_wsgi
+ExecReload=/bin/kill -s HUP $MAINPID
+StandardOutput=append:/var/log/gunicorn-nominatim.log
+StandardError=inherit
+PrivateTmp=true
+TimeoutStopSec=5
+KillMode=mixed
+
+[Install]
+WantedBy=multi-user.target
+```
+
+This sets up gunicorn with 4 workers (`-w 4` in ExecStart). Each worker runs
+its own Python process using
+[`NOMINATIM_API_POOL_SIZE`](../customize/Settings.md#nominatim_api_pool_size)
+connections to the database to serve requests in parallel.
+
+Make the new service known to systemd and start it:
+
+``` sh
+sudo systemctl daemon-reload
+sudo systemctl enable nominatim
+sudo systemctl start nominatim
+```
+
+This sets the service up, so that Nominatim is automatically started
+on reboot.
+
+### Configuring nginx
+
+To make the service available to the world, you need to proxy it through
+nginx. Add the following definition to the default configuration:
+
+``` nginx
+upstream nominatim_service {
+  server unix:/run/nominatim.sock fail_timeout=0;
+}
+
+server {
+    listen 80;
+    listen [::]:80;
+
+    root /var/www/html;
+    index /search;
+
+    location / {
+            proxy_set_header Host $http_host;
+            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_set_header X-Forwarded-Proto $scheme;
+            proxy_redirect off;
+            proxy_pass http://nominatim_service;
+    }
+}
+```
+
+Reload nginx with
+
+```
+sudo systemctl reload nginx
+```
+
+and you should be able to see the status of your server under
+`http://localhost/status`.

docs/admin/Import.md

@@ -254,26 +254,70 @@ successfully.
 nominatim admin --check-database
 ```
 
-Now you can try out your installation by running:
+Now you can try out your installation by executing a simple query on the
+command line:
+
+``` sh
+nominatim search --query Berlin
+```
+
+or, when you have a reverse-only installation:
+
+``` sh
+nominatim reverse --lat 51 --lon 45
+```
+
+If you want to run Nominatim as a service, you need to make a choice between
+running the traditional PHP frontend or the new experimental Python frontend.
+Make sure you have installed the right packages as per
+[Installation](Installation.md#software).
+
+#### Testing the PHP frontend
+
+You can run a small test server with the PHP frontend like this:
 
 ```sh
 nominatim serve
 ```
 
-This runs a small test server normally used for development. You can use it
-to verify that your installation is working. Go to
-`http://localhost:8088/status.php` and you should see the message `OK`.
-You can also run a search query, e.g. `http://localhost:8088/search.php?q=Berlin`.
+Go to `http://localhost:8088/status.php` and you should see the message `OK`.
+You can also run a search query, e.g. `http://localhost:8088/search.php?q=Berlin`
+or, for reverse-only installations a reverse query,
+e.g. `http://localhost:8088/reverse.php?lat=27.1750090510034&lon=78.04209025`.
+
+Do not use this test server in production.
+To run Nominatim via webservers like Apache or nginx, please continue reading
+[Deploy the PHP frontend](Deployment-PHP.md).
+
+#### Testing the Python frontend
+
+To run the test server against the Python frontend, you must choose a
+web framework to use, either starlette or falcon. Make sure the appropriate
+packages are installed. Then run
+
+``` sh
+nominatim serve --engine falcon
+```
+
+or
+
+``` sh
+nominatim serve --engine starlette
+```
+
+Go to `http://localhost:8088/status.php` and you should see the message `OK`.
+You can also run a search query, e.g. `http://localhost:8088/search.php?q=Berlin`
+or, for reverse-only installations a reverse query,
+e.g. `http://localhost:8088/reverse.php?lat=27.1750090510034&lon=78.04209025`.
 
-Note that search query is not supported for reverse-only imports. You can run a
-reverse query, e.g. `http://localhost:8088/reverse.php?lat=27.1750090510034&lon=78.04209025`.
+Do not use this test server in production.
+To run Nominatim via webservers like Apache or nginx, please continue reading
+[Deploy the Python frontend](Deployment-Python.md).
 
-To run Nominatim via webservers like Apache or nginx, please read the
-[Deployment chapter](Deployment.md).
 
-## Adding search through category phrases
+## Enabling search by category phrases
 
-If you want to be able to search for places by their type through
+To be able to search for places by their type using
 [special phrases](https://wiki.openstreetmap.org/wiki/Nominatim/Special_Phrases)
 you also need to import these key phrases like this:
 

docs/admin/Installation.md

@@ -54,6 +54,8 @@ For running Nominatim:
   * [PyICU](https://pypi.org/project/PyICU/)
   * [PyYaml](https://pyyaml.org/) (5.1+)
   * [datrie](https://github.com/pytries/datrie)
+
+When running the PHP frontend:
   * [PHP](https://php.net) (7.3+)
   * PHP-pgsql
   * PHP-intl (bundled with PHP)
@@ -83,7 +85,7 @@ Take into account that the OSM database is growing fast.
 Fast disks are essential. Using NVME disks is recommended.
 
 Even on a well configured machine the import of a full planet takes
-around 2 days. On traditional spinning disks, 7-8 days are more realistic.
+around 2 days. When using traditional SSDs, 4-5 days are more realistic.
 
 ## Tuning the PostgreSQL database
 
@@ -115,15 +117,6 @@ you might consider setting:
 and even reduce `autovacuum_work_mem` further. This will reduce the amount
 of memory that autovacuum takes away from the import process.
 
-For the initial import, you should also set:
-
-    fsync = off
-    full_page_writes = off
-
-Don't forget to re-enable them after the initial import or you risk database
-corruption.
-
-
 ## Downloading and building Nominatim
 
 ### Downloading the latest release