Add basic program structure and first use case

This MR adds the command-line option parser and the first simple use case of exporting a full exposure dataset (building and tile entities) for a country.

\rfc @shinde @tara @laurens

exposureshare/exposureshare.py

@@ -17,5 +17,108 @@
 # along with this program. If not, see http://www.gnu.org/licenses/.
 
 
-def main():
-    pass
+import logging
+import sys
+import argparse
+import configparser
+import datetime
+from exposurelib import SpatiaLiteExposure
+
+# Add a logger printing error, warning, info and debug messages to the screen
+logger = logging.getLogger()
+logger.setLevel(logging.INFO)
+logger.addHandler(logging.StreamHandler(sys.stdout))
+
+
+def command_line_interface():
+    """
+    Command-line interface of the exposure-share program. The first command-line option is the
+    command defining what type of extract will be created:
+        `full`: Full exposure will be extracted. This includes level-18 tile entities and
+                building entities.
+        `tile`: Exposure will be extracted at level-18 quad-tree tiles by aggregating all
+                entities (`building` and `residual`) within each tile.
+    The command require these mandatory options:
+        `-e`: Filepath of the exposure database.
+        `-c`: Config file (INI-type) describing the access to the tile database. Also needed
+              for `local` as the boundaries and tiles will be copied over to the local
+              SpatiaLite database.
+        `-i`: ISO 3166-1 alpha-3 code of the country for which the exposure is to be imported.
+    """
+
+    # Create the argument parser
+    parser = argparse.ArgumentParser(description="Exposure-Share")
+    parser_shared = argparse.ArgumentParser(add_help=False)
+    parser_shared.add_argument(
+        "-i",
+        "--country-iso-code",
+        required=True,
+        type=str,
+        help="ISO 3166-1 alpha-3 code of the country",
+    )
+    parser_shared.add_argument(
+        "-e",
+        "--exposure-database",
+        required=True,
+        type=str,
+        help="Filepath to the SpatiaLite exposure database",
+    )
+    parser_shared.add_argument(
+        "-c",
+        "--config-file",
+        required=True,
+        type=str,
+        help="Filepath of the config file for accessing the Tiles database",
+    )
+
+    # Prepare for subparsers
+    subparsers = parser.add_subparsers(help="sub-command help", dest="command")
+    # Create the parser for the 'full' command
+    subparsers.add_parser(
+        "full",
+        help="Full exposure will be extracted. "
+        + "This includes level-18 tile entities and building entities.",
+        parents=[parser_shared],
+    )
+    # Create the parser for the 'tile' command
+    subparsers.add_parser(
+        "tile",
+        help="Exposure will be extracted at level-18 quad-tree tiles "
+        + "by aggregating all entities (`building` and `residual`) within each tile.",
+        parents=[parser_shared],
+    )
+
+    # Read arguments from command line.
+    args = parser.parse_args()
+
+    postgis_config = configparser.ConfigParser()
+    postgis_config.read(args.config_file)
+
+    # Initialize database
+    output_database_object = SpatiaLiteExposure(args.exposure_database)
+    output_database_object.connect()
+    output_database_object.create_tables()
+
+    exposure_source_db_config = postgis_config["Exposure"]
+    obm_source_db_config = postgis_config["OBM"]
+
+    start_time = datetime.datetime.now()
+    logger.info("Start time: %s" % start_time)
+
+    if args.command == "full":
+        output_database_object.import_from_postgis(
+            exposure_source_db_config,
+            obm_source_db_config,
+            country_iso_code=args.country_iso_code,
+            copy_buildings=False,
+        )
+    elif args.command == "tile":
+        raise ValueError("Option `tile` not yet implemented")
+    else:
+        raise ValueError(f"Unknown option `{args.command}`")
+
+    logger.info("Execution time: %s" % (datetime.datetime.now() - start_time))
+
+
+if __name__ == "__main__":
+    command_line_interface()