From fcc9bbe998e0e2eed074058156168d0a52195c17 Mon Sep 17 00:00:00 2001
From: Heiko Heiko <heiko@heiko.org>
Date: Thu, 21 Aug 2014 17:14:46 +0200
Subject: [PATCH] add: trace tx via the api

---
 pyethereum/apiserver.py | 60 ++++++++++++++++++++++++++++++++++++++++-
 pyethereum/ethclient.py |  8 +++++-
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/pyethereum/apiserver.py b/pyethereum/apiserver.py
index 29e59599e..6acea0b9c 100644
--- a/pyethereum/apiserver.py
+++ b/pyethereum/apiserver.py
@@ -7,9 +7,12 @@
 from pyethereum.chainmanager import chain_manager
 from pyethereum.peermanager import peer_manager
 import pyethereum.dispatch as dispatch
-from pyethereum.blocks import block_structure
+from pyethereum.blocks import block_structure, Block
 import pyethereum.signals as signals
 from pyethereum.transactions import Transaction
+import pyethereum.processblock as processblock
+import pyethereum.utils as utils
+import pyethereum.rlp as rlp
 
 logger = logging.getLogger(__name__)
 base_url = '/api/v02a'
@@ -176,6 +179,61 @@ def get_pending():
 
 
 
+# ########### Trace ############
+
+class TraceLogHandler(logging.Handler):
+    def __init__(self):
+        logging.Handler.__init__(self)
+        self.buffer = []
+
+    def emit(self, record):
+        self.buffer.append(record)
+
+
+@app.get(base_url + '/trace/<txhash>')
+def trace(txhash):
+    """
+    /trace/<hexhash>        return trace for transaction
+    """
+    logger.debug('GET trace/ %s', txhash)
+    try: # index
+        tx, blk = chain_manager.index.get_transaction(txhash.decode('hex'))
+    except (KeyError, TypeError):
+        return bottle.abort(404, 'Unknown Transaction  %s' % txhash)
+
+    # get the state we had before this transaction
+    test_blk = Block.init_from_parent(blk.get_parent(),
+                                        blk.coinbase,
+                                        extra_data=blk.extra_data,
+                                        timestamp=blk.timestamp,
+                                        uncles=blk.uncles)
+    pre_state = test_blk.state_root
+    for i in range(blk.transaction_count):
+        tx_lst_serialized, sr, _ = blk.get_transaction(i)
+        if utils.sha3(rlp.encode(tx_lst_serialized)) == tx.hash:
+            break
+        else:
+            pre_state = sr
+    test_blk.state.root_hash = pre_state
+
+    # collect debug output
+    tl = TraceLogHandler()
+    tl.setLevel(logging.DEBUG)
+    processblock.logger.addHandler(tl)
+
+    # apply tx (thread? we don't want logs from other invocations)
+    processblock.apply_transaction(test_blk, tx)
+
+    # stop collecting debug output
+    processblock.logger.removeHandler(tl)
+
+    # format
+    formatter = logging.Formatter('%(name)s:%(message)s')
+    res = '\n'.join(formatter.format(l) for l in tl.buffer)
+    return dict(trace=res)
+
+
+
 # ######## Accounts ############
 @app.get(base_url + '/accounts/')
 def accounts():
diff --git a/pyethereum/ethclient.py b/pyethereum/ethclient.py
index c1fd52913..02621698d 100755
--- a/pyethereum/ethclient.py
+++ b/pyethereum/ethclient.py
@@ -95,6 +95,11 @@ def gettx(self, id):
     def getpending(self):
         return self.json_get_request(path='/pending/')
 
+    def trace(self, id):
+        res = self.json_get_request(path='/trace/%s' % id)
+        if 'trace' in res:
+          return res['trace']
+        return res
 
 doc = \
 """ethclient
@@ -115,7 +120,7 @@ def getpending(self):
   pyethclient getblock [options] <blockid_hex_or_num>
   pyethclient gettx [options] <txid_hex>
   pyethclient getpending [options]
-
+  pyethclient trace [options] <txid_hex>
 
 Options:
   -h --help                 Show this screen
@@ -155,6 +160,7 @@ def main():
                     getblock=(api.getblock, arguments['<blockid_hex_or_num>']),
                     gettx=(api.gettx, arguments['<txid_hex>']),
                     trace=(api.trace, arguments['<txid_hex>']),
+                    getpending=(api.getpending,)
                     )
     for k in cmd_map:
         if arguments.get(k):