This container generates user-requested netCDF files using ncks and makes them available for download via THREDDS.
The Unidata netCDF tools must be installed. This package can be installed with poetry:
apt get install nco
github clone http://github.com/pacificclimate/ncpartitioner
poetry install
To do end-to-end testing, you will also need a THREDDS instance running on your workstation, though the test suite does not need a working THREDDS instance. Set the environment variables:
OUTPUT_DIR- file directory to put the partitioned files in. It should be accessible to THREDDSTHREDDS_HTTP_BASE- the base URL for the THREDDS http server (probably ends /fileserver); a user will be redirected to download the completed fileTHREDDS_DAP_BASE- the base URL for the THREDDS openDAP server (probably ends /dodsC): used to fulfill metadata requestsDATA_ROOT- directory under which all data is found; prevents files outside the directory from being served
Run with flask:
poetry run flask run
Run the test suite (environment variables will be provided by pytest and do not need to be set):
poetry run pytest
This server assumes all files to be downloaded are netCDF4 files with dimensions named lat, lon, and time, and that all variables one might wish to download have those dimensions. Timeless files or station-based geometries cannot be downloaded via this server. Only one variable may be downloaded at a time.
Request format is indicated by concatenating an extension onto the filepath parameter. Some request formats require an additional targets parameter. Request attributes other than targets and filepath are ignored.
This server supports four request formats. Three of them are simply redirected to the THREDDS server:
https://server/partition/?filepath=path/to/file.nc.dds&targets=time
Redirects to a THREDDS page displaying metadata about the time dimension. This request accepts a single dimension.
https://server/partition/?filepath=path/to/file.nc.das
Redirects to a THREDDS page displaying metadata about all variables and attributes.targets attribute is ignored, if present.
https://server/partition/?filepath=path/to/file.nc.ascii&targets=lat,lon
Redirects to a THREDDS page displaying values for the requested dimension variable(s) in ASCII format. This server will only display values for dimension variables (lat, lon, and time) via this request type. OpenDAP standards support requesting any variable in ASCII format this way, but since THREDDS has a 500MB maximum file size for DAP requests, this server only supports requesting the dimension variables, not multidimensional data variables.
https://server/partition/?filepath=path/to/file.nc.nc&targets=time[0:10],lat[0:20],lon[0:30],tasmax[0:10][0:20][0:30]
Creates a file with the requested dimensions using ncks, then redirects the user to the THREDDS page to download the newly created file. Note that the variable is always trimmed to the hyperslab specified in the dimensions portion of the targets attribute; if the variable portion of the targets attribute is different, it will be overruled.
