Modified get_environment to provide multiple fields.

tests/test_algorithm.py

@@ -136,6 +136,28 @@ class TestMiscellaneousAPI(TestCase):
             concurrent=True,
         )
 
+    def test_get_environment(self):
+        expected_env = {
+            'arena': 'backtest',
+            'data_frequency': 'minute',
+            'start': pd.Timestamp('2006-01-03 14:31:00+0000', tz='UTC'),
+            'end': pd.Timestamp('2006-01-04 21:00:00+0000', tz='UTC'),
+            'capital_base': 100000.0,
+            'platform': 'zipline'
+        }
+
+        def initialize(algo):
+            self.assertEqual('zipline', algo.get_environment())
+            self.assertEqual(expected_env, algo.get_environment('*'))
+
+        def handle_data(algo, data):
+            pass
+
+        algo = TradingAlgorithm(initialize=initialize,
+                                handle_data=handle_data,
+                                sim_params=self.sim_params)
+        algo.run(self.source)
+
     def test_get_open_orders(self):
 
         def initialize(algo):

zipline/algorithm.py

@@ -545,8 +545,19 @@ class TradingAlgorithm(object):
             self.add_history(bars, freq, 'volume')
 
     @api_method
-    def get_environment(self):
-        return self._environment
+    def get_environment(self, field='platform'):
+        env = {
+            'arena': self.sim_params.arena,
+            'data_frequency': self.sim_params.data_frequency,
+            'start': self.sim_params.first_open,
+            'end': self.sim_params.last_close,
+            'capital_base': self.sim_params.capital_base,
+            'platform': self._environment
+        }
+        if field == '*':
+            return env
+        else:
+            return env[field]
 
     def add_event(self, rule=None, callback=None):
         """

zipline/finance/trading.py

@@ -396,6 +396,9 @@ class SimulationParameters(object):
         self.data_frequency = data_frequency
         self.sids = sids
 
+        # copied to algorithm's environment for runtime access
+        self.arena = 'backtest'
+
         self._update_internal()
 
     def _update_internal(self):