Source code for pyart.config

"""
Py-ART configuration.

"""

import os
import traceback
import warnings


# the path to the default configuration file
_dirname = os.path.dirname(__file__)
_DEFAULT_CONFIG_FILE = os.path.join(_dirname, 'default_config.py')


[docs]def load_config(filename=None): """ Load a Py-ART configuration from a config file. The default values for a number of Py-ART parameters and metadata is controlled by a single Python configuration file. An self-descriping example of this file can be found in the Py-ART source directory named **default_config.py**. These defaults can modified by setting the environmental variable `PYART_CONFIG` to point to a new configuration file. If this variable is not set then the settings contained in the **default_config.py** file are used. The code the configuration file is executed as-is with full permission, this may present a security issue, do not load un-trusted configuration files. The recommended method for changing these defaults is for users to copy this file into their home directory, rename it to .pyart_config.py, make any changes, and adjust their login scripts to set the PYART_CONFIG environmental variable to point to .pyart_config.py in their home directory. Py-ART's configuration can also be modified within a script or shell session using this function, the modification will last until a the end of the script/session or until a new configuration is loaded. Parameters ---------- filename : str Filename of configuration file. If None the default configuration file is loaded from the Py-ART source code directory. """ if filename is None: filename = _DEFAULT_CONFIG_FILE # these are private since they should not be accessed by users or other # modules, use the get_ functions. global _DEFAULT_METADATA global _FILE_SPECIFIC_METADATA global _FIELD_MAPPINGS global _FILL_VALUE global _DEFAULT_FIELD_NAMES global _DEFAULT_FIELD_COLORMAP global _DEFAULT_FIELD_LIMITS try: from importlib.machinery import SourceFileLoader cfile = SourceFileLoader('metadata_config', filename).load_module() except ImportError: import imp cfile = imp.load_source('metadata_config', filename) _DEFAULT_METADATA = cfile.DEFAULT_METADATA _FILE_SPECIFIC_METADATA = cfile.FILE_SPECIFIC_METADATA _FIELD_MAPPINGS = cfile.FIELD_MAPPINGS _FILL_VALUE = cfile.FILL_VALUE _DEFAULT_FIELD_NAMES = cfile.DEFAULT_FIELD_NAMES _DEFAULT_FIELD_COLORMAP = cfile.DEFAULT_FIELD_COLORMAP _DEFAULT_FIELD_LIMITS = cfile.DEFAULT_FIELD_LIMITS return
# load the configuration from the enviromental parameter if it is set # if the load fails issue a warning and load the default config. _config_file = os.environ.get('PYART_CONFIG') if _config_file is None: load_config(_DEFAULT_CONFIG_FILE) else: try: load_config(_config_file) except: msg = ("\nLoading configuration from PYART_CONFIG enviromental " "variable failed:" "\n--- START IGNORED TRACEBACK --- \n" + traceback.format_exc() + "\n --- END IGNORED TRACEBACK ---" "\nLoading default configuration") warnings.warn(msg) load_config(_DEFAULT_CONFIG_FILE)
[docs]def get_metadata(p): """ Return a dictionary of metadata for a given parameter, p. An empty dictionary will be returned in no metadata dictionary exists for parameter p. """ if p in _DEFAULT_METADATA: return _DEFAULT_METADATA[p].copy() else: return {}
[docs]def get_fillvalue(): """ Return the current fill value. """ return _FILL_VALUE
[docs]def get_field_name(field): """ Return the field name from the configuration file for a given field. """ return str(_DEFAULT_FIELD_NAMES[field])
[docs]def get_field_colormap(field): """ Return the colormap name from the configuration file for a field name. """ if field in _DEFAULT_FIELD_COLORMAP: return _DEFAULT_FIELD_COLORMAP[field] else: import matplotlib.cm return matplotlib.cm.get_cmap().name
[docs]def get_field_limits(field, container=None, selection=0): """ Return the data limits from the configuration file for a given field, radar and sweep. Parameters ---------- field : str Field name. container : Radar, Grid or None, optional This is an optional parameter that will be use to get informations related to the field, like for instace nyquist velocity. selection : int, optional Selection of the data in the container, case container is a Radar this is the sweep to be considered. Returns ------- vmin, vmax: 2-tuplet of float Minimun and Maximun teorical value for field, if field is not in the configuration file returns (None, None). """ if field in _DEFAULT_FIELD_LIMITS: limits = _DEFAULT_FIELD_LIMITS[field] if callable(limits): limits = limits(container, selection) return limits else: return None, None
[docs]def get_field_mapping(filetype): """ Return a copy of the default field mapping for a given file type. Parameters ---------- filetype : str Filetype to return field mappings for. Returns ------- field_mappings : dict Dictionary mapping field names from one type to another. """ return _FIELD_MAPPINGS[filetype].copy()
[docs]class FileMetadata(): """ A class for accessing metadata needed when reading files. Parameters ---------- filetype: str Type of file being read. field_names : dict Dictionary mapping file field names to radar fields names. additional_metadata : dict of dicts Additional metadata to use during read. file_field_names : bool True to keep the field names in the file. exclude_fields : list of strings Fields to exclude during readings. include_fields : list of strings Fields to include during readings. """ def __init__(self, filetype, field_names=None, additional_metadata=None, file_field_names=False, exclude_fields=None, include_fields=None): """ Initialize. """ # parse filetype parameter if filetype in _FILE_SPECIFIC_METADATA: self._file_specific_metadata = _FILE_SPECIFIC_METADATA[filetype] else: self._file_specific_metadata = {} # parse additional_metadata if additional_metadata is None: self._additional_metadata = {} else: self._additional_metadata = additional_metadata # parse field_names and file_field_names if file_field_names: self._field_names = None elif field_names is None and filetype in _FIELD_MAPPINGS: # if filetype is missing there is no mapping self._field_names = _FIELD_MAPPINGS[filetype] else: self._field_names = field_names # parse exclude_fields if exclude_fields is None: self._exclude_fields = [] else: self._exclude_fields = exclude_fields if include_fields is None: self._include_fields = None else: self._include_fields = include_fields
[docs] def get_metadata(self, p): """ Retrieve metadata for a parameter `p`. Parameters ---------- p : str Parameter to retrieve metadata for. Returns ------- dic : dict Dictionary of metadata for the parameter. """ # additional_metadata is queued first if p in self._additional_metadata: return self._additional_metadata[p].copy() # then the file specific metadata elif p in self._file_specific_metadata: return self._file_specific_metadata[p].copy() # and finally the default metadata elif p in _DEFAULT_METADATA: return _DEFAULT_METADATA[p].copy() # return a empty dict if the parameter is in none of the above else: return {}
[docs] def __call__(self, p): """ Retrieve metadata for parameter `p`. """ return self.get_metadata(p)
[docs] def get_field_name(self, file_field_name): """ Return the name radar field for a given file field name Parameters ---------- file_field_name : str Field name in file being read. Returns ------- field_name : str or None Field name in radar object fields dictionary, None indicated that the field should not be included. """ if self._field_names is None: field_name = file_field_name elif file_field_name in self._field_names: field_name = self._field_names[file_field_name] else: return None # field is not mapped if field_name in self._exclude_fields: return None # field is excluded elif self._include_fields is not None: if not field_name in self._include_fields: return None else: return field_name else: return field_name