Coin Notifications

This application listens for transaction events from bitcoind, tracks confirmations, and sends out SMS messages for bitcoin addresses that you're interested in.

This project will only send notifications for addresses on the receive-side of transactions. It extracts destinations from raw transactions, but the main-net simply seees too many transactions per block to make it viable to get all the inputs over RPC. I think the best way to notify on inputs would be to index all unspent transactions along with precomputed addresses in a database so they can be fetched rapidly, but that's outside the scope of this project.

• Parses raw transactions and blocks from bitcoind
• Extracts addresses from the standard transaction scripts
• Keeps the best 30 blocks and sends SMS messages on requested confirmation counts.

Dev

bitcoind only includes ZeroMQ support in the linux version, so if you're on macOS you need to set up a VM to run it.

This project includes an Vagrantfile and Ansible roles to provision it. Just follow these steps:

Prerequisites:

• virtualbox
• vagrant
• ansible

$ vagrant up
$ ssh-add .vagrant/machines/default/virtualbox/private_key
$ ansible-playbook -i ansible/hosts ansible/provision.yml -l dev
$ vagrant ssh

Try out a notification:

1. cd coin_notifications
2. manually add twilio creds to coinpusher/config/notifier_config.exs (this will be automated in the future)
3. iex -S mix
4. To get notifications for confirmations 0, 2, and 5 (note address uses single-quotes): iex(1)> CoinPusher.NotificationsController.add_listener('<address>', "<phone>", [0, 2, 5])
5. $ btccli generate 101 # to free up the first coinbase tx
6. $ btccli sendtoaddress <address> 1.0
7. You should see the first 0-confirmation notification go out.
8. When subsequent blocks are generated you should see confirmations 2 and 5 go out.

When you're ssh'd into a box provisioned by the included Ansible roles, you will also have a command btccli which will execute against the active bitcoin network and data directory, so you don't have to use bitcoin-cli -regtest -rpcuser= ... -datadir=...

For example:

$ btccli getinfo
{
  "version": 140300,
  "protocolversion": 70015,
  ...
}