Factor out repeated code for most cli apps, along with classes specific to traffic script

apps/contract-migration/scripts/local/transfer.py

@@ -0,0 +1,39 @@
+# standard imports
+import logging
+import random
+
+# external imports
+from cic_eth.api.api_task import Api
+
+logging.basicConfig(level=logging.WARNING)
+logg = logging.getLogger()
+
+queue = 'cic-eth'
+name = 'erc20_transfer'
+
+
+def do(token_pair, sender, recipient, sender_balance, aux, block_number, tx_index):
+
+    logg.debug('running {} {} {} {}'.format(__name__, token_pair, sender, recipient))
+
+    decimals = token_pair[0].decimals()
+    balance_units = int(sender_balance / decimals)
+
+    if balance_units == 0:
+        return (AttributeError('sender {} has zero balance'), None, 0,)
+
+    spend_units = random.randint(1, balance_units)
+    spend_value = spend_units * decimals
+
+    api = Api(
+        str(aux['chain_spec']),
+        queue=queue,
+        callback_param='{}:{}:{}:{}'.format(aux['redis_host_callback'], aux['redis_port_callback'], aux['redis_db'], aux['redis_channel']),
+        callback_task='cic_eth.callbacks.redis.redis',
+        callback_queue=queue,
+        )
+    t = api.transfer(sender, recipient, spend_value, token_pair[0].symbol())
+
+    changed_sender_balance = sender_balance - spend_value
+
+    return (None, t, changed_sender_balance,)