source: flex_extract.git/python/MARSretrieval.py @ 991df6a

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#************************************************************************
# TODO AP
# -
#************************************************************************
#*******************************************************************************
# @Author: Anne Fouilloux (University of Oslo)
#
# @Date: October 2014
#
# @Change History:
#
#   November 2015 - Leopold Haimberger (University of Vienna):
#        - optimized displayInfo
#        - optimized dataRetrieve and seperate between python and shell
#          script call
#
#   February 2018 - Anne Philipp (University of Vienna):
#        - applied PEP8 style guide
#        - added documentation
#        - applied some minor modifications in programming style/structure
#
# @License:
#    (C) Copyright 2015-2018.
#
#    This software is licensed under the terms of the Apache Licence Version 2.0
#    which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# @Class Description:
#    A MARS revtrieval has a specific syntax with a selection of keywords and
#    their corresponding values. This class provides the necessary functions
#    by displaying the selected parameters and their values and the actual
#    retrievement of the data through a mars request or a Python web api
#    interface. The initialization already expects all the keyword values.
#
# @Class Content:
#    - __init__
#    - displayInfo
#    - dataRetrieve
#
#*******************************************************************************

# ------------------------------------------------------------------------------
# MODULES
# ------------------------------------------------------------------------------
import subprocess
import os

ecapi = True
try:
    import ecmwfapi
except ImportError:
    ecapi = False

# ------------------------------------------------------------------------------
# CLASS
# ------------------------------------------------------------------------------
class MARSretrieval:
    '''
    Class for submitting MARS retrievals.

    A description of MARS keywords/arguments and examples of their
    values can be found here:
    https://software.ecmwf.int/wiki/display/UDOC/\
                   Identification+keywords#Identificationkeywords-class

    '''

    def __init__(self, server, marsclass = "ei", type = "", levtype = "",
                 levelist = "", repres = "", date = "", resol = "", stream = "",
                 area = "", time = "", step = "", expver = "1", number = "",
                 accuracy = "", grid = "", gaussian = "", target = "",
                 param = ""):
        '''
        @Description:
            Initialises the instance of the MARSretrieval class and
            defines and assigns a set of the necessary retrieval parameters
            for the FLEXPART input data.
            A description of MARS keywords/arguments, their dependencies
            on each other and examples of their values can be found here:

            https://software.ecmwf.int/wiki/display/UDOC/MARS+keywords

        @Input:
            self: instance of MARSretrieval
                For description see class documentation.

            server: instance of ECMWFService (from ECMWF Web-API)
                This is the connection to the ECMWF data servers.
                It is needed for the pythonic access of ECMWF data.

            marsclass: string, optional
                Characterisation of dataset. E.g. EI (ERA-Interim),
                E4 (ERA40), OD (Operational archive), ea (ERA5).
                Default is the ERA-Interim dataset "ei".

            type: string, optional
                Determines the type of fields to be retrieved.
                Selects between observations, images or fields.
                Examples for fields: Analysis (an), Forecast (fc),
                Perturbed Forecast (pf), Control Forecast (cf) and so on.
                Default is an empty string.

            levtype: string, optional
                Denotes type of level. Has a direct implication on valid
                levelist values!
                E.g. model level (ml), pressure level (pl), surface (sfc),
                potential vorticity (pv), potential temperature (pt)
                and depth (dp).
                Default is an empty string.

            levelist: string, optional
                Specifies the required levels. It has to have a valid
                correspondence to the selected levtype.
                Examples: model level: 1/to/137, pressure levels: 500/to/1000
                Default is an empty string.

            repres: string, optional
                Selects the representation of the archived data.
                E.g. sh - spherical harmonics, gg - Gaussian grid,
                ll - latitude/longitude, ...
                Default is an empty string.

            date: string, optional
                Specifies the Analysis date, the Forecast base date or
                Observations date. Valid formats are:
                Absolute as YYYY-MM-DD or YYYYMMDD.
                Default is an empty string.

            resol: string, optional
                Specifies the desired triangular truncation of retrieved data,
                before carrying out any other selected post-processing.
                The default is automatic truncation (auto), by which the lowest
                resolution compatible with the value specified in grid is
                automatically selected for the retrieval.
                Users wanting to perform post-processing from full spectral
                resolution should specify Archived Value (av).
                The following are examples of existing resolutions found in
                the archive: 63, 106, 159, 213, 255, 319, 399, 511, 799 or 1279.
                This keyword has no meaning/effect if the archived data is
                not in spherical harmonics representation.
                The best selection can be found here:
                https://software.ecmwf.int/wiki/display/UDOC/\
                      Retrieve#Retrieve-Truncationbeforeinterpolation
                Default is an empty string.

            stream: string, optional
                Identifies the forecasting system used to generate the data.
                E.g. oper (Atmospheric model), enfo (Ensemble forecats), ...
                Default is an empty string.

            area: string, optional
                Specifies the desired sub-area of data to be extracted.
                Areas can be defined to wrap around the globe.

                Latitude values must be given as signed numbers, with:
                    north latitudes (i.e. north of the equator)
                        being positive (e.g: 40.5)
                    south latitutes (i.e. south of the equator)
                        being negative (e.g: -50.5)
                Longtitude values must be given as signed numbers, with:
                    east longitudes (i.e. east of the 0 degree meridian)
                        being positive (e.g: 35.0)
                    west longitudes (i.e. west of the 0 degree meridian)
                        being negative (e.g: -20.5)

                E.g.: North/West/South/East
                Default is an empty string.

            time: string, optional
                Specifies the time of the data in hours and minutes.
                Valid values depend on the type of data: Analysis time,
                Forecast base time or First guess verification time
                (all usually at synoptic hours: 00, 06, 12 and 18 ).
                Observation time (any combination in hours and minutes is valid,
                subject to data availability in the archive).
                The syntax is HHMM or HH:MM. If MM is omitted it defaults to 00.
                Default is an empty string.

            step: string, optional
                Specifies the forecast time step from forecast base time.
                Valid values are hours (HH) from forecast base time. It also
                specifies the length of the forecast which verifies at
                First Guess time.
                E.g. 1/3/6-hourly
                Default is an empty string.

            expver: string, optional
                The version of the dataset. Each experiment is assigned a
                unique code (version). Production data is assigned 1 or 2,
                and experimental data in Operations 11, 12 ,...
                Research or Member State's experiments have a four letter
                experiment identifier.
                Default is "1".

            number: string, optional
                Selects the member in ensemble forecast run. (Only then it
                is necessary.) It has a different meaning depending on
                the type of data.
                E.g. Perturbed Forecasts: specifies the Ensemble forecast member
                Default is an empty string.

            accuracy: string, optional
                Specifies the number of bits per value to be used in the
                generated GRIB coded fields.
                A positive integer may be given to specify the preferred number
                of bits per packed value. This must not be greater than the
                number of bits normally used for a Fortran integer on the
                processor handling the request (typically 32 or 64 bit).
                Within a compute request the accuracy of the original fields
                can be passed to the result field by specifying accuracy=av.
                Default is an empty string.

            grid: string, optional
                Specifies the output grid which can be either a Gaussian grid
                or a Latitude/Longitude grid. MARS requests specifying
                grid=av will return the archived model grid.

                Lat/Lon grid: The grid spacing needs to be an integer
                fraction of 90 degrees e.g. grid = 0.5/0.5

                Gaussian grid: specified by a letter denoting the type of
                Gaussian grid followed by an integer (the grid number)
                representing the number of lines between the Pole and Equator,
                e.g.
                grid = F160 - full (or regular) Gaussian grid with
                       160 latitude lines between the pole and equator
                grid = N320 - ECMWF original reduced Gaussian grid with
                       320 latitude lines between the pole and equator,
                       see Reduced Gaussian Grids for grid numbers used at ECMWF
                grid = O640 - ECMWF octahedral (reduced) Gaussian grid with
                       640 latitude lines between the pole and equator
                Default is an empty string.

            gaussian: string, optional
                This parameter is deprecated and should no longer be used.
                Specifies the desired type of Gaussian grid for the output.
                Valid Gaussian grids are quasi-regular (reduced) or regular.
                Keyword gaussian can only be specified together with
                keyword grid. Gaussian without grid has no effect.
                Default is an empty string.

            target: string, optional
                Specifies a file into which data is to be written after
                retrieval or manipulation. Path names should always be
                enclosed in double quotes. The MARS client supports automatic
                generation of multiple target files using MARS keywords
                enclosed in square brackets [ ].  If the environment variable
                MARS_MULTITARGET_STRICT_FORMAT is set to 1 before calling mars,
                the keyword values will be used in the filename as shown by
                the ecCodes GRIB tool grib_ls -m, e.g. with
                MARS_MULTITARGET_STRICT_FORMAT set to 1 the keywords time,
                expver and param will be formatted as 0600, 0001 and 129.128
                rather than 600, 1 and 129.
                Default is an empty string.

            param: string, optional
                Specifies the meteorological parameter.
                The list of meteorological parameters in MARS is extensive.
                Their availability is directly related to their meteorological
                meaning and, therefore, the rest of directives specified
                in the MARS request.
                Meteorological parameters can be specified by their
                GRIB code (param=130), their mnemonic (param=t) or
                full name (param=temperature).
                The list of parameter should be seperated by a "/"-sign.
                E.g. 130/131/133
                Default is an empty string.

        @Return:
            <nothing>
        '''

        self.server = server
        self.marsclass = marsclass
        self.type = type
        self.levtype = levtype
        self.levelist = levelist
        self.repres = repres
        self.date = date
        self.resol = resol
        self.stream = stream
        self.area = area
        self.time = time
        self.step = step
        self.expver = expver
        self.number = number
        self.accuracy = accuracy
        self.grid = grid
        self.gaussian = gaussian
        self.target = target
        self.param = param

        return


    def displayInfo(self):
        '''
        @Description:
            Prints all class attributes and their values.

        @Input:
            self: instance of MARSretrieval
                For description see class documentation.

        @Return:
            <nothing>
        '''
        # Get all class attributes and their values as a dictionary
        attrs = vars(self)

        # iterate through all attributes and print them
        # with their corresponding values
        for item in attrs.items():
            if item[0] in ('server'):
                pass
            else:
                print(item[0] + ': ' + str(item[1]))

        return

    def dataRetrieve(self):
        '''
        @Description:
            Submits a MARS retrieval. Depending on the existence of
            ECMWF Web-API it is submitted via Python or a
            subprocess in the Shell. The parameter for the mars retrieval
            are taken from the defined class attributes.

        @Input:
            self: instance of MARSretrieval
                For description see class documentation.

        @Return:
            <nothing>
        '''
        # Get all class attributes and their values as a dictionary
        attrs = vars(self)

        # convert the dictionary of attributes into a comma
        # seperated list of attributes with their values
        # needed for the retrieval call
        s = 'ret'
        for k, v in attrs.iteritems():
            if k in ('server'):
                continue
            if k == 'marsclass':
                k = 'class'
            if v == '':
                continue
            if k.lower() == 'target':
                target = v
            else:
                s = s + ',' + k + '=' + str(v)

        # MARS request via Python script
        if self.server is not False:
            try:
                self.server.execute(s, target)
            except:
                print('MARS Request failed, \
                    have you already registered at apps.ecmwf.int?')
                raise IOError
            if os.stat(target).st_size == 0:
                print('MARS Request returned no data - please check request')
                raise IOError
        # MARS request via extra process in shell
        else:
            s += ',target = "' + target + '"'
            p = subprocess.Popen(['mars'], stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE, bufsize=1)
            pout = p.communicate(input=s)[0]
            print(pout.decode())

            if 'Some errors reported' in pout.decode():
                print('MARS Request failed - please check request')
                raise IOError

            if os.stat(target).st_size == 0:
                print('MARS Request returned no data - please check request')
                raise IOError

        return