Source code for

Download process for Sentinel Hub Statistical API
import logging
import copy
import os
import concurrent.futures

from .sentinelhub_client import SentinelHubDownloadClient
from ..constants import MimeType
from ..decoding import decode_data as decode_data_function
from ..io_utils import read_data, write_data

LOGGER = logging.getLogger(__name__)

[docs]class SentinelHubStatisticalDownloadClient(SentinelHubDownloadClient): """ A special download client for Sentinel Hub Statistical API Besides a normal download from Sentinel Hub services it implements an additional process of retrying and caching """ _RETIRABLE_ERRORS = ['EXECUTION_ERROR', 'TIMEOUT'] def __init__(self, *args, n_interval_retries=1, max_retry_threads=5, **kwargs): """ :param n_interval_retries: Number of retries if a request fails just for a certain timestamp. (This parameter is experimental and might be changed in the future.) :type n_interval_retries: int :param max_retry_threads: Number of threads used for retrying. (This parameter is experimental and might be changed in the future.) :type max_retry_threads: int """ super().__init__(*args, **kwargs) self.n_interval_retries = n_interval_retries self.max_retry_threads = max_retry_threads def _single_download(self, request, _): """ Method for downloading a single request """ request.raise_if_invalid() if not (request.save_response or request.return_data): return None request_path, response_path = request.get_storage_paths() download_required = self.redownload or response_path is None or not os.path.exists(response_path) if download_required: response_content = self._execute_download(request) stats_response = decode_data_function(response_content, request.data_type) else: LOGGER.debug('Reading locally stored data from %s instead of downloading', response_path) self._check_cached_request_is_matching(request, request_path) stats_response = read_data(response_path, data_format=request.data_type) failed_time_intervals = {} for index, stat_info in enumerate(stats_response['data']): if self._has_retriable_error(stat_info): failed_time_intervals[index] = stat_info['interval'] n_succeeded_intervals = 0 if failed_time_intervals: LOGGER.debug('Failed for %s intervals, retrying by downloading per interval', len(failed_time_intervals)) retried_responses = self._download_per_interval(request, failed_time_intervals) n_succeeded_intervals = sum('error' not in stat_info for stat_info in retried_responses.values()) stats_response['data'] = [ retried_responses.get(index, stat_info) for index, stat_info in enumerate(stats_response['data']) ] if request_path and request.save_response and (self.redownload or not os.path.exists(request_path)): request_info = request.get_request_params(include_metadata=True) write_data(request_path, request_info, data_format=MimeType.JSON) LOGGER.debug('Saved request info to %s', request_path) if request.save_response and (download_required or n_succeeded_intervals > 0): write_data(response_path, stats_response, data_format=request.data_type) LOGGER.debug('Saved data to %s', response_path) if request.return_data: return stats_response return None def _download_per_interval(self, request, time_intervals): """ Download statistics per each time interval """ interval_requests = [] for time_interval in time_intervals.values(): interval_request = copy.deepcopy(request) interval_request.post_values['aggregation']['timeRange'] = time_interval interval_requests.append(interval_request) with concurrent.futures.ThreadPoolExecutor(max_workers=self.max_retry_threads) as executor: stat_info_responses = list(, interval_requests)) return dict(zip(time_intervals, stat_info_responses)) def _execute_single_stat_download(self, request): """ Makes sure a download for a single time interval is retried """ for retry_count in range(self.n_interval_retries): response = self._execute_download(request) stat_response = decode_data_function(response, request.data_type) stat_info = stat_response['data'][0] if not self._has_retriable_error(stat_info) or retry_count == self.n_interval_retries - 1: return stat_info raise ValueError('No more retries available, download unsuccessful') def _has_retriable_error(self, stat_info): """ Checks if a dictionary of Stat API info for a single time interval has an error that can fixed by retrying a request """ error_type = stat_info.get('error', {}).get('type') return error_type in self._RETIRABLE_ERRORS