#!/usr/bin/env python
__doc__ = """
Extracts and fetches NetCDF files from a Metalink file containing an URL, and outputs the NetCDF file at a given
index of the list.
"""
import argparse
import logging
import os
import sys
from tempfile import TemporaryDirectory
[docs]
CUR_DIR = os.path.abspath(os.path.dirname(__file__))
sys.path.insert(0, CUR_DIR)
# root to allow 'from weaver import <...>'
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(CUR_DIR))))
# place weaver specific imports after sys path fixing to ensure they are found from external call
# pylint: disable=C0413,wrong-import-order
from weaver import xml_util # isort:skip # noqa: E402
from weaver.processes.builtin.utils import get_package_details, validate_reference # isort:skip # noqa: E402
from weaver.utils import fetch_file # isort:skip # noqa: E402
from weaver.processes.builtin.utils import is_netcdf_url # isort:skip # noqa: E402
PACKAGE_NAME, PACKAGE_BASE, PACKAGE_MODULE = get_package_details(__file__)
# setup logger since it is not run from the main 'weaver' app
[docs]
LOGGER = logging.getLogger(PACKAGE_MODULE)
LOGGER.addHandler(logging.StreamHandler(sys.stdout))
LOGGER.setLevel(logging.INFO)
# process details
__version__ = "1.4"
__title__ = "Metalink to NetCDF"
__abstract__ = __doc__ # NOTE: '__doc__' is fetched directly, this is mostly to be informative
[docs]
def m2n(metalink_reference, index, output_dir):
# type: (str, int, str) -> None
LOGGER.info(
"Got arguments: metalink_reference=%s index=%s output_dir=%s", metalink_reference, index, output_dir
)
LOGGER.info("Process '%s' execution starting...", PACKAGE_NAME)
LOGGER.info("Process '%s' output directory: [%s].", PACKAGE_NAME, output_dir)
try:
if not os.path.isdir(output_dir):
raise ValueError(f"Output dir [{output_dir}] does not exist.")
LOGGER.info("Validating Metalink file: [%s]", metalink_reference)
validate_reference(metalink_reference, is_file=True)
with TemporaryDirectory(prefix=f"wps_process_{PACKAGE_NAME}_") as tmp_dir:
LOGGER.info("Fetching Metalink file: [%s]", metalink_reference)
metalink_path = fetch_file(metalink_reference, tmp_dir, timeout=10, retry=3)
LOGGER.info("Reading Metalink file: [%s]", metalink_path)
xml_data = xml_util.parse(metalink_path)
LOGGER.debug("Parsing Metalink file references.")
meta_ns = xml_data.getroot().nsmap[None] # metalink URN namespace, pass explicitly otherwise xpath fails
meta_version = xml_data.xpath("/m:metalink[1]", namespaces={"m": meta_ns})
if (
(meta_version and meta_version[0].get("version") == "4.0") or
os.path.splitext(metalink_path)[-1] == ".meta4"
):
ns_xpath = f"/m:metalink/m:file[{index}]/m:metaurl"
else:
ns_xpath = f"/m:metalink/m:files/m:file[{index}]/m:resources[1]/m:url"
nc_file_url = str(xml_data.xpath(f"string({ns_xpath})", namespaces={"m": meta_ns}))
if not is_netcdf_url(nc_file_url):
raise ValueError(f"Resolved file URL [{nc_file_url}] is not a valid NetCDF reference.")
LOGGER.info("Validating NetCDF reference: [%s]", nc_file_url)
validate_reference(nc_file_url, is_file=True)
LOGGER.info("Fetching NetCDF reference [%s] from Metalink file [%s]", nc_file_url, metalink_reference)
fetch_file(nc_file_url, output_dir)
except Exception as exc:
# log only debug for tracking, re-raise and actual error wil be logged by top process monitor
LOGGER.error("Process '%s' raised an unhandled exception: [%s]", PACKAGE_NAME, exc)
raise
LOGGER.info("Process '%s' execution completed.", PACKAGE_NAME)
[docs]
def main(*args):
# type: (*str) -> None
LOGGER.info("Parsing inputs of '%s' process.", PACKAGE_NAME)
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("-i", metavar="metalink", type=str, required=True,
help="Metalink file to be parsed for NetCDF file names.")
parser.add_argument("-n", metavar="index", type=int, required=True,
help="Index of the specific NetCDF file to extract. First element's index is 1.")
parser.add_argument("-o", metavar="outdir", default=CUR_DIR,
help="Output directory of the retrieved NetCDF files extracted by name from the Metalink file.")
args = parser.parse_args(args)
sys.exit(m2n(args.i, args.n, args.o))
if __name__ == "__main__":
main(*sys.argv[1:])