Run a geoslurp-enabled PostgreSQL database with PostGIS

The geoslurp client tools, allow users to download and register various (Earth science) datasets. In order for it work it requires a working PostgreSQL database server with the PostGIS extension enabled. This docker image provides such a running PostgreSQL instance, and, upon initialization, it creates a geoslurp database suitable for interacting with geoslurp clients. Inside the docker image a geoslurp client is also installed. This facilitates managing the database from within the docker container, and in the future possibly adding things like cronjobs for automatic updating of datasets.

Step 1: Setup the environment variables

Before building and running the docker container, several important environment variables need/may to be set. The install_n_runexample.sh script illustrates how this may work in combination with the docker-compose file.

Mount points (optional, make sure to uncomment the appropriate section in docker-compose.yml)

#External mount point of the PGdata volume 
export PG_DATA=/path/to/pgdata
#External mount point of the default out-of-db dataset storage location root
export GEOSLURP_DATAROOT=/external/mount/path/where/outofdb/dataisstored

# INTERNAL CACHE directory for tempoerary data downloads
export GEOSLURP_CACHE=/external/mount/path/to/cachefolder

Users and passwords

#Postgresql administrator and password
export POSTGRES_USER=gsadmin
export POSTGRES_PASSWORD=CHANGETHISTOSOMETHINGELSE

# day to day user which can add and manage datasets from within the docker container
export GEOSLURP_USER=marge
export GEOSLURP_UPASSWD=CHANGETHISTOO
#Set this UID to match the UID of an outside user which has write permission in GEOSLURP_DATAROOT and GEOSLURP_CACHE (leave at 1000 for no change)
export GEOSLURP_UID=1000

#readonly 'consumer' user which has read access to the database, but cannot change tables
export GEOSLURP_ROUSER=greadonly
export GEOSLURP_ROUPASSWD=IAMSERIOUSCHANGETHESEPASSWORDS

Step 2. Run docker-compose

Once the environment variables are set up one can adapt, build and run the docker container with docker-compose

docker-compose build
docker-compose up -d

When everything worked according to plan, one can test the connection by logging in the database locally with psql -h localhost -U $GEOSLURP_USER -d geoslurp

Setting up the database without docker

When a suitable PostgreSQL database is already running, it is also possible to use the scripts in the docker-geoslurp repository to initialize a geoslurp-enabled database in the existing instance. The steps which are then needed are the following:

1. Locally install a geoslurp client : pip install geoslurp
2. Set the environment variables as desribed in Step 1 above. Optionally set the environment variable GEOSLURP_HOST to point to the hostname of the database server, when working remotely.
3. Get and run the geoslurp initialization script:

   wget https://raw.githubusercontent.com/strawpants/docker-geoslurp/master/setupgeoslurp.sh
   bash ./setupgeoslurp.sh
   

Interacting with the database

Since the database interface is standardized there is a variety of ways to interact with the tables in the database. It is recommended to use the readonly user where possible, in order to avoid unintended table modifications and deletions. A selection of possibilities are:

• Use the geoslurp client
• Browse and use the database with QGIS
• Use the interactive PostgreSQL terminal psql
• Directly open a PostgreSQL table with GDAL
• Well, basically using anything which supports the PostgreSQL protocol...