EOSIO Watcher Plugin + ZeroMQ

This is a modified version of the EOSIO Watcher Plugin (https://github.com/eosauthority/eosio-watcher-plugin) with the ZeroMQ Plugin (https://github.com/cc32d9/eos_zmq_plugin). It uses the approach in the watcher plugin where only transactions that make it into an accepted block are processed, but uses ZeroMQ to avoid http endpoint saturation when replaying the blockchain. Additionally since ZeroMQ push is a blocking operation, it is guaranteed that events (blocks) are processed in order at the work receiver endpoint performing the pull.

Requirements

• You'll need to install libzmq for your system as well as pkg-config. Please see installation instructions here: http://zeromq.org/intro:get-the-software
• Additionally you'll need to install the C++ bindings for your system: https://github.com/zeromq/cppzmq

Building the plugin [Install on your nodeos server]

1. Copy watcher_plugin folder to <eosio-source-dir>/plugins/ You should now have <eosio-source-dir>/plugins/watcher_plugin
2. Add the following line to <eosio-source-dir>/plugins/CMakeLists.txt with other add_subdirectory items

add_subdirectory(watcher_plugin)

3. Add the following line to the bottom of <eosio-source-dir>/programs/nodeos/CMakeLists.txt

target_link_libraries( nodeos PRIVATE -Wl,${whole_archive_flag} watcher_plugin -Wl,${no_whole_archive_flag})

4. Install dependencies:

macOS

brew install pkg-config
brew link pkg-config
brew install zmq

Download the C++ bindings for ZeroMQ by cloning this repository: https://github.com/zeromq/cppzmq, and copy zmq.hpp to /usr/local/include putting it next to zmq.h

4. Build and install nodeos with eosio_build.sh and eosio_install.sh. You could even just cd <eosio-source-dir>/build and then sudo make install

How to setup on your nodeos

Enable this plugin using --plugin option to nodeos or in your config.ini. Use nodeos --help to see options used by this plugin.

Configuration

Add the following to config.ini to enable the plugin:

#Enable watcher plugin
plugin = eosio::watcher_plugin

#Set account:action so eosauthority:spaceinvader or just eosauthority: for all actions on eosauthority
watch=chintaitest1:

#Age limit in seconds for blocks to send notifications. No age limit if set to negative. Used to prevent old actions from trigger HTTP request while on replay (seconds)
watch-age-limit = -1

#ZMQ sender socket binding
zmq-sender-bind = tcp://127.0.0.1:3001