prepare docker-compose for ckanext-spatial

modify CKAN Dockerfile to install system packages required for ckanext-spatial
modify postgres Dockerfile to use postgis image
add postgres Dockerfile script to set permissions for postgis tables to ckan user
add working installation steps to docs

Dockerfile

@@ -14,6 +14,10 @@ RUN apt-get -q -y update && apt-get -q -y upgrade && \
         libpq-dev \
         git-core \
         postgresql-client \
+        python-dev \
+        libxml2-dev \
+        libxslt-dev \
+        libgeos-dev \
 	&& apt-get -q clean
 
 # Define environment variables

contrib/docker/postgresql/Dockerfile

@@ -1,4 +1,5 @@
-FROM postgres:9.6
+#FROM postgres:9.6
+FROM mdillon/postgis
 MAINTAINER Open Knowledge
 
 # Allow connections; we don't map out any ports so only linked docker containers can connect
@@ -13,3 +14,5 @@ ARG DS_RO_PASS
 # Include datastore setup scripts
 ADD /docker-entrypoint-initdb.d/00_create_datastore.sql ./00_create_datastore.sql
 ADD /docker-entrypoint-initdb.d/10_set_permissions.sql ./10_set_permissions.sql
+ADD /docker-entrypoint-initdb.d/20_postgis_permissions.sql ./20_postgis_permissions.sql
+

contrib/docker/postgresql/docker-entrypoint-initdb.d/20_postgis_permissions.sql

@@ -0,0 +1,3 @@
+CREATE EXTENSION POSTGIS;
+ALTER VIEW geometry_columns OWNER TO ckan;
+ALTER TABLE spatial_ref_sys OWNER TO ckan;

doc/maintaining/installing/install-from-docker-compose.rst

@@ -251,8 +251,31 @@ In this example we'll install `ckanext-geoview <https://github.com/ckan/ckanext-
 Some extensions require database upgrades, often through paster scripts.
 E.g., ``ckanext-spatial``::
 
+
+    # Enter the running ckan container:
+    docker exec -it ckan bash
+
+    # Inside the running ckan container
+    source $CKAN_VENV/bin/activate && cd $CKAN_VENV/src/
+    git clone https://github.com/ckan/ckanext-spatial.git
+    cd ckanext-spatial
+    pip install -r pip-requirements.txt
+    python setup.py install && python setup.py develop
+    exit
+
+    docker exec -it db psql -U ckan -f 20_postgis_permissions.sql
     docker exec -it ckan /usr/local/bin/ckan-paster --plugin=ckanext-spatial spatial initdb -c /etc/ckan/ckan.ini
 
+    sudo vim /var/lib/docker/volumes/docker_ckan_config/_data/ckan.ini
+
+    # in plugins, add:
+    spatial_metadata spatial_query
+
+    ckanext.spatial.search_backend = solr
+
+.. note:: In order to work on your own forks of CKAN extensions, the container's
+  ssh publickey must be added to the respective repository's authorized keys.
+
 b. Modify CKAN config
 
 Follow the respective extension's instructions to set CKAN config variables::