getTransaction bug in for confirmation() in watcher context.

[gabidi]

When a transaction received for a watching wallet, cyphernode's get_transaction will attempt to first locate the transaction in spender wallet, then iterate over watcher wallets. This results in a series of JSON objects:

2019-12-12T23:57:01+0000 1777 [confirmation] tx_details={"result":null,"error":{"code":-5,"message":"Invalid or non-wallet transaction
id"},"id":null}                              
{"result":{"amount":0.00100000,"confirmations":0,...l}

This creates an issue when the transaction is being parsed assuming only one JSON object has been returned, which results in the failure of a watching wallet's txn to be inserted into the watching_tx table:

2019-12-12T23:59:22+0000 2061 [confirmation] fees=0.00000145 
sh: 0                                                               
0: bad number                                                                                                                          
2019-12-12T23:59:22+0000 2061 sqlite3 -cmd ".timeout 20000" /proxy/db/proxydb "INSERT OR IGNORE INTO tx (txid, hash, confirmations, tim
ereceived, fee, size, vsize, is_replaceable, blockhash, blockheight, blocktime, raw_tx) VALUES ("4a10e28a2bb4b5b9dda2b038aec8357733d506
8171bbcf254c4274f81cc9e3c8", "98484b169015889c7a940a4af266ad888cde87f7e54398a1ce05b7423cf5615b", 0 
0, null                                                             
1576195162, 0.00000145, 226, 145, 0, null, null, null, readfile('rawtx-4a10e28a2bb4b5b9dda2b038aec8357733d5068171bbcf254c4274f81cc9e3c8
.blob'))"                                                                                                                              
Error: near "0": syntax error     

Issue has already been fixed in PR https://github.com/SatoshiPortal/cyphernode/pull/150 This issue is opened for commit reference

[Kexkey]

I think that all this is caused by one small addition you made in the code. Here are some details:

• Bitcoin Core notifies Cyphernode for any tx happening on its wallets (with walletnotify=) -- the notification happens on spending also, not only on watching;
• The Invalid or non-wallet transaction id happens when Cyphernode receives a notif but the tx is not part of the watching wallet -- in this case, we just disregard the notif:

  tx_details=$(get_transaction ${txid})
  returncode=$?
  trace_rc ${returncode}
  trace "[confirmation] tx_details=${tx_details}"
  if [ "${returncode}" -ne "0" ]; then
  trace "[confirmation] Transaction not in watcher, exiting."
  return 0
  fi

• the get_transaction only checks in the watching wallet if not otherwise specified; also, it doesn't return multiple values, there's only 1 tx with a certain txid...;
• Nothing in confirmation.sh deals with the spending wallet;
• The problem here sh: 0 and 0: bad number is due to what you added here: https://github.com/SatoshiPortal/cyphernode/pull/150/commits/43ddfc4acb0b63aa03e9716b6a1b19b75f5c8f3a#diff-1efdbdd6c16c9f9d14a6c0441e0a7702R35
• That previous change also breaks the returncode value, that's why the "Transaction not in watcher, exiting." part doesn't run;
• I think that if you break the "get_transaction" and the "jq... select" parts in two operations (so that the returncode is right), everything will work correctly.

Let me know what you think! Thanks!

[gabidi]

Hey @Kexkey , Thanks for taking the time to reply. Please excuse me for not having supplied detailed information and written up a proper ticket about the issue. You are right , the issue has nothing to do with Spending wallet but with watching wallets. I have no idea why i said spending in that ticket. If you would be kind enough to allow me to provide more detail and context to the issue:

So assuming the context of a transaction comes in where we have multiple watcher wallets and one of them is concerned with the txn. confirmation.sh will eventually call get_transaction which will call send_to_watcher_node: https://github.com/SatoshiPortal/cyphernode/blob/760c9954cacb7e8f6c5215327c2e82185f9a92d3/proxy_docker/app/script/sendtobitcoinnode.sh#L5

1. send_to_watcher_node will First try the default watcher wallet by calling: https://github.com/SatoshiPortal/cyphernode/blob/760c9954cacb7e8f6c5215327c2e82185f9a92d3/proxy_docker/app/script/sendtobitcoinnode.sh#L7

2. send_to_bitcoin_node will echo it's result, meaning: a. it finds the txn within the first watcher wallet attempted return code will ne 0 and we go back up the stack (get_transaction <-send_to_watcher_node <- sendtobitcoinnode) with only ONE json output, everything works great. b. However if the txn is not found in the default watcher wallet, send_to_bitcoin_node will output the usual not found :

   {"result":null,"error":{"code":-5,"message":"Invalid or non-wallet transaction
   id"},"id":null}

   but then send_to_watcher_node will detect a return code ne 0 and call https://github.com/SatoshiPortal/cyphernode/blob/760c9954cacb7e8f6c5215327c2e82185f9a92d3/proxy_docker/app/script/sendtobitcoinnode.sh#L14 send_to_watcher_node_wallet , which will call send_to_bitcoin_node, which will output another json object with the txn if found or not, and thus we get the TWO json objects send back to the get_transaction call , described in this issue.

   {"result":null,"error":{"code":-5,"message":"Invalid or non-wallet transaction
   id"},"id":null}                              
   {"result":{"amount":0.00100000,"confirmations":0,...etc..}

3. Now since tx_details has two JSON objects (one on each line) https://github.com/SatoshiPortal/cyphernode/blob/43ddfc4acb0b63aa03e9716b6a1b19b75f5c8f3a/proxy_docker/app/script/confirmation.sh#L35 all functions down stream expect , as you aptly put it, only one object. So for example: https://github.com/SatoshiPortal/cyphernode/blob/43ddfc4acb0b63aa03e9716b6a1b19b75f5c8f3a/proxy_docker/app/script/confirmation.sh#L73

given the output returned by get_transaction call in this issue (two objects, first being not found result , the second being found) will result in an output of

null\n
0

Since the first JSON object has nothing in result and the second does indeed have 0 in the .result.confirmations field. Even if we do add a jq -rc -c flag for compact the output will be 'null0'

This will cause a bunch of insert SQL statements to fail down stream and the rest is history.

Thus adding https://github.com/SatoshiPortal/cyphernode/commit/43ddfc4acb0b63aa03e9716b6a1b19b75f5c8f3a#diff-1efdbdd6c16c9f9d14a6c0441e0a7702R35 Make sure to only take the correct output the rest of the script is expecting.

I hope i didn't cause even more confusion lol.

You are 100% right about breaking the return code by adding JQ and will push a commit that moves the jq select statement to after the return code of get_transaction is checked. Just want to make sure i'm completely wrong here.

Let me know what you think about the above. Thank you so much again ! G

[Kexkey]

Ok I got it! We should capture the output of send_to_bitcoin_node in a variable (inside send_to_watcher_node) instead of displaying it. If returncode is 0, then we can echo it.

Thanks so much!

[Kexkey]

Was this fixed with PR#150 ?

[gabidi]

Yes sir. I'll close the issue.