Transaction Generator Python library

This is for python 3.6+ only

A transaction generator library for the Harmony Blockchain. It utilizes the CLI to generate transactions.

Documentation can be found here and example scripts that use the transaction generator can be found in the root of this directory with the suffix _example.py

Note that this only works on MacOS or Linux. It could possibly work on WSL, but this is untested.

Install

You can install the library from pypi using the following command:

python3 -m pip install harmony-transaction-generator

You will require the latest version of pyhmy (which may not install if you already have it). You can get the latest with the following command:

python3 -m pip install pyhmy --upgrade

Development Installation

Clone this repo and run:

make install

Examples

Example script when running for devnet can be seen here

You can run localnet_example.py if you have a localnet running. To start a localnet, reference the main harmony repo to set up your ev environment, then run test/debug.sh in the main repo.

The localnet is an easy way to develop your scripts without relying or using real network currency.

Important note about funding keys

One must have keys in the keystore that have funds on ALL shards (if one wishes to funds accounts on all shards). Note that one account does NOT have to have funds on all shard, but across all accounts in the keystore, there should be funds on all shards

This is because the library only does same shard transfers when funding to be conservative.

How it works

The docs can be found here.

Take a look at the localnet_example.py for some idea of how it works. Essentially, it follows a source / sink model for transaction generation (explained more in the start function here). Moreover, the annotations of the config in localnet_example.py should give a better idea of how to use the library.

A video demoing library can be seen here

Analysis

The analysis module of this library has a verify_transaction function that looks at the transaction logs and checks if said transactions appear on the blockchain. Refer to here for mode details on how it works.

The library logs everything it can, so one can read the log files to analyze it. The filepath/filename can be accessed with the filename attribute of the logger, for example tx_gen.Loggers.transaction.filename.

Note that all times in the logs are in UTC.

Caveat

The package has NOT been thoroughly tested so please report bugs and/or PR fixes if you find any, thank you!

Troubleshooting Errors While Testing

Possible fixes

• Backup and clear keystore at ~/.hmy_cli/account-keys
• Update pyhmy to latest version, can be checked here.

Check version with python3 -m pip list | grep pyhmy

• If current balance is not enough for requested transfer, try increasing the 'INIT_SRC_ACC_BAL_PER_SHARD' value in the config file