make basemaps configurable (#261) (#16)

* Persist env variables where possible

* Make basemap configurable

Implements wmo-im/wis2box#261

docker/pygeoapi-config.yml

@@ -10,8 +10,8 @@ server:
     pretty_print: false
     limit: 500
     map:
-        url: https://tile.openstreetmap.org/{z}/{x}/{y}.png
-        attribution: '&copy; <a href="https://openstreetmap.org/copyright">OpenStreetMap contributors</a>'
+        url: ${WIS2BOX_BASEMAP_URL}
+        attribution: ${WIS2BOX_BASEMAP_ATTRIBUTION}
     templates:
         path: /pygeoapi/pygeoapi/templates
 

wis2box_api/admin.py

@@ -92,6 +92,11 @@ def write_config(self, config):
         # validate pygeoapi configuration
         validate_config(config)
 
+        with open(self.PYGEOAPI_CONFIG, encoding='utf8') as fh:
+            conf = yaml.safe_load(fh)
+
+        config = json_merge_patch.merge(config, conf)
+
         # write pygeoapi configuration
         LOGGER.debug('Writing pygeoapi configutation')
         self.yaml_dump(config, self.PYGEOAPI_CONFIG)