README.md

filesfdw

A postgres foreign data wrapper to help keep track of data files

Installation

Install with

pip install git+https://github.com/ASRCsoft/filesfdw.git

Make sure to install the package to the python installation used by postgres (should be the operating system's python 2).

Setup

After installing, create the multicorn extension in the postgres database:

CREATE EXTENSION multicorn;

Restart postgres (from the terminal):

sudo service postgresql restart

In the database, create the foreign data servers and tables. Option base is the folder holding the data files:

# lidar csv files
CREATE SERVER lidar_csv_srv foreign data wrapper multicorn options(wrapper 'filesfdw.fdw.LidarCsv');
CREATE FOREIGN TABLE lidar_csv (date date, site text, radial text, scan text, environment text, config text, wind text, whole text) server lidar_csv_srv options(base '/farm1/mesonet/data/lidar_raw/');

# microwave radiometer csv files
CREATE SERVER mwr_csv_srv foreign data wrapper multicorn options(wrapper 'filesfdw.fdw.MwrCsv');
CREATE FOREIGN TABLE mwr_csv (time timestamp, site text, lv0 text, lv1 text, lv2 text, tip text, healthstatus text) server mwr_csv_srv options(base '/farm1/mesonet/data/mwr_raw/');

# lidar netcdf files
CREATE SERVER lidar_nc_srv foreign data wrapper multicorn options(wrapper 'filesfdw.fdw.LidarNetcdf');
CREATE FOREIGN TABLE lidar_netcdf (date date, site text, netcdf text) server lidar_nc_srv options(base '/farm1/mesonet/data/lidar_netcdf/');

Usage

The foreign data tables lidar_csv, mwr_csv, and lidar_netcdf can now be queried just like any other postgres database. When a query is run, postgres runs a python script that finds the relevant data files and extracts some information from them (date/time, site, type of data file). The results of that script are then sent back to postgres and treated like a regular postgres table.