improve support for using custom csv2bufr template in wis2box (#854)

* improve support for using custom csv2bufr template in wis2box

* add forgotten l

* rephrase intro

docker-compose.yml

@@ -41,7 +41,7 @@ services:
       interval: 5s
       retries: 100
     volumes:
-      - ${WIS2BOX_HOST_DATADIR}/mappings:/data/wis2box/mappings:ro
+      - ${WIS2BOX_HOST_DATADIR}/mappings:/data/wis2box/mappings:rw
 
   minio:
     container_name: wis2box-minio

docs/source/reference/running/data-pipeline-plugins.rst

@@ -25,11 +25,11 @@ list below describes each plugin and provides an example data mappings configura
 
 This plugin converts CSV observation data into BUFR using `csv2bufr`_. 
 
-A `template` is required to convert the CSV columns to BUFR encoded values.  See `csv2bufr-examples`_ on how to create a template or use one of the built-in templates.
+A `template` is required to convert the CSV columns to BUFR encoded values, you can use the built-in templates or create your own custom template.
 
 A ``file-pattern`` is used to filter on incoming data based on a regular expression.  
 
-A typical csv2bufr plugin workflow definition would by defined as follows:
+A typical csv2bufr plugin workflow using one of the built-in templates would be defined as follows:
 
 .. code-block:: yaml
 
@@ -39,11 +39,41 @@ A typical csv2bufr plugin workflow definition would by defined as follows:
          notify: true  # trigger GeoJSON publishing for API and UI
          file-pattern: '^.*\.csv$'
 
-The default templates are defined by the `csv2bufr-templates`_ repository.
+In this the example `aws-template` refers to the `aws_example.json` template defined by the `csv2bufr-templates`_ repository.
 
-To use a custom template, the template should be located in the ``$WIS2BOX_HOST_DATADIR/mappings`` directory and the `wis2box.env` file should include `CSV2BUFR_TEMPLATES=${WIS2BOX_DATADIR}/mappings`.	
+Environment variables can be set in `wis2box.env` to customize the behavior of the csv2bufr-plugin within the wis2box, see `csv2bufr-environment-variables`_ for the full list of environment variables.
+
+Using the csv2bufr plugin with a custom template
+++++++++++++++++++++++++++++++++++++++++++++++++
+
+To create a custom template for the csv2bufr plugin in the wis2box, you can follow these steps:
+
+Login to the wis2box-api container:
+
+.. code-block:: bash
+
+    python3 wis2box-ctl.py login wis2box-api
+
+Within the wis2box-api container you can using the command `csv2bufr mappings create` and provide the BUFR-descriptors you want to encode as arguments.
+Make sure to redirect the output to a file in the `/data/wis2box/mappings` directory (which is mapped to the host system at `$WIS2BOX_HOST_DATADIR/mappings`)
+
+For example, to create a custom template for the csv2bufr plugin with the BUFR-descriptors 301150, 301011, 301012, 301021, 007031, 302001, run the following command:
+
+.. code-block:: bash
+
+     csv2bufr mappings create 301150 301011 301012 301021 007031 302001 --output /data/wis2box/mappings/my_own_template.json
+
+See the `Manual on Codes`_ to find the BUFR-descriptors you need.
+
+Exit the container after creating the custom template:
+
+.. code-block:: bash
+
+    exit
+
+You can edit the template file on the host system at `$WIS2BOX_HOST_DATADIR/mappings/my_own_template.json` to customize the template further.
 
-The plugin configuration would then be defined as follows:
+After creating the custom template, you can use it in the csv2bufr plugin configuration in MCF as follows:
 
 .. code-block:: yaml
 
@@ -53,7 +83,11 @@ The plugin configuration would then be defined as follows:
          notify: true  # trigger GeoJSON publishing for API and UI
          file-pattern: '^.*\.csv$'
 
-Environment variables can be set in `wis2box.env` to customize the behavior of the csv2bufr-plugin within the wis2box, see `csv2bufr-environment-variables`_ for the full list of environment variables.
+And/or you can select the new template in the Plugin Configuration of the Dataset Mappings Editor in the wis2box-webapp:
+
+.. image:: ../_static/csv2bufr_custom_template.png
+   :alt: csv2bufr custom template
+   :align: center
 
 ``wis2box.data.bufr4.ObservationDataBUFR2GeoJSON``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -170,9 +204,9 @@ For example, to publish GRIB2 data matching the file-pattern ``^.*_(\d{8})\d{2}.
 See :ref:`data-mappings` for a full example data mapping configuration.
 
 .. _`csv2bufr`: https://csv2bufr.readthedocs.io/en/v0.8.5/
-.. _`csv2bufr-examples`: https://csv2bufr.readthedocs.io/en/v0.8.5/example.html
 .. _`csv2bufr-environment-variables`: https://csv2bufr.readthedocs.io/en/v0.8.5/installation.html#environment-variables
 .. _`csv2bufr-templates`: https://github.com/wmo-im/csv2bufr-templates
 .. _`bufr2geojson`: https://github.com/wmo-im/bufr2geojson
 .. _`synop2bufr`: https://synop2bufr.readthedocs.io
 
+.. _`Manual on Codes`: https://library.wmo.int/records/item/35625-manual-on-codes-volume-i-2-international-codes