More examples, fix erroneous input stat in execution context.

examples/basic_extract_transform_load_of_bags.py

@@ -0,0 +1,33 @@
+import time
+from random import randint
+
+from bonobo import Bag
+from bonobo.core.graphs import Graph
+from bonobo.core.strategies.executor import ThreadPoolExecutorStrategy
+from bonobo.ext.console import ConsoleOutputPlugin
+
+
+def extract():
+    yield Bag(topic='foo')
+    yield Bag(topic='bar')
+    yield Bag(topic='baz')
+
+
+def transform(topic: str):
+    wait = randint(0, 1)
+    time.sleep(wait)
+    return Bag.inherit(title=topic.title(), wait=wait)
+
+
+def load(topic: str, title: str, wait: int):
+    print('{} ({}) wait={}'.format(title, topic, wait))
+
+
+Strategy = ThreadPoolExecutorStrategy
+
+if __name__ == '__main__':
+    etl = Graph()
+    etl.add_chain(extract, transform, load)
+
+    s = Strategy()
+    s.execute(etl, plugins=[ConsoleOutputPlugin()])

examples/basic_extract_transform_load_of_dicts.py

@@ -0,0 +1,35 @@
+import time
+from random import randint
+
+from bonobo.core.graphs import Graph
+from bonobo.core.strategies.executor import ThreadPoolExecutorStrategy
+from bonobo.ext.console import ConsoleOutputPlugin
+
+
+def extract():
+    yield {'topic': 'foo'}
+    yield {'topic': 'bar'}
+    yield {'topic': 'baz'}
+
+
+def transform(row):
+    wait = randint(0, 1)
+    time.sleep(wait)
+    return {
+        'topic': row['topic'].title(),
+        'wait': wait,
+    }
+
+
+def load(s):
+    print(s)
+
+
+Strategy = ThreadPoolExecutorStrategy
+
+if __name__ == '__main__':
+    etl = Graph()
+    etl.add_chain(extract, transform, load)
+
+    s = Strategy()
+    s.execute(etl, plugins=[ConsoleOutputPlugin()])