Add first prototype of layer tool

omtgen.py

@@ -0,0 +1,98 @@
+#!/usr/bin/env python
+"""
+Usage:
+  omtgen tm2source <tileset> [--host=<host>] [--port=<port>] [--database=<dbname>] [--user=<user>] [--password=<pw>]
+  omtgen --help
+  omtgen --version
+Options:
+  --help              Show this screen.
+  --version           Show version.
+  --host=<host>       PostGIS host.
+  --port=<port>       PostGIS port.
+  --database=<dbname> PostGIS database name.
+  --user=<user>       PostGIS user.
+  --password=<pw>     PostGIS password.
+"""
+import sys
+import yaml
+import collections
+from docopt import docopt
+
+DbParams = collections.namedtuple('DbParams', ['dbname', 'host', 'port',
+                                               'password', 'user'])
+
+
+def generate_layer(layer_def, db_params):
+    layer = layer_def['layer']
+    datasource = layer['datasource']
+    tm2layer = {
+        'id': layer['id'],
+        'description': layer['description'],
+        'srs': layer['srs'],
+        'properties': {
+            'buffer-size': layer['buffer_size']
+        },
+        'fields': layer['fields'],
+        'Datasource': {
+          'extent': [-20037508.34, -20037508.34, 20037508.34, 20037508.34],
+          'geometry_field': datasource.get('geometry_field', 'geom'),
+          'key_field': datasource.get('key_field', ''),
+          'key_field_as_attribute': datasource.get('key_field_as_attribute', ''),
+          'max_size': datasource.get('max_size', 512),
+          'port': db_params.port,
+          'srid': datasource['srid'],
+          'table': datasource['query'],
+          'type': 'postgis',
+          'host': db_params.host,
+          'dbname': db_params.dbname,
+          'user': db_params.user,
+          'password': db_params.password,
+        }
+    }
+    return tm2layer
+
+
+def generate_tm2source(tileset_filename, db_params):
+    with open(tileset_filename, 'r') as stream:
+        try:
+            tileset = yaml.load(stream)['tileset']
+        except yaml.YAMLError as e:
+            print('Could not parse ' + tileset_filename)
+            print(e)
+            sys.exit(403)
+
+    tm2 = {
+        'attribution': tileset['attribution'],
+        'center': tileset['center'],
+        'description': tileset['description'],
+        'maxzoom': tileset['maxzoom'],
+        'minzoom': tileset['minzoom'],
+        'name': tileset['name'],
+        'Layer': [],
+    }
+
+    for layer_filename in tileset['layers']:
+        with open(layer_filename, 'r') as stream:
+            try:
+                layer_def = yaml.load(stream)
+                tm2layer = generate_layer(layer_def, db_params)
+                tm2['Layer'].append(tm2layer)
+            except yaml.YAMLError as e:
+                print('Could not parse ' + layer_filename)
+                print(e)
+                sys.exit(403)
+
+    return tm2
+
+if __name__ == '__main__':
+    args = docopt(__doc__, version=0.1)
+    if args.get('tm2source'):
+        db_params = DbParams(
+            dbname=args['--database'],
+            port=int(args['--port']),
+            user=args['--user'],
+            password=args['--password'],
+            host=args['--host']
+        )
+        tm2 = generate_tm2source(args['<tileset>'], db_params)
+        print(yaml.dump(tm2))