python

Python Workshop

bitcoinkernel exposes a C API. It mostly operates on pointers (which usually, but not always) are managed by the user. This combined with the fact that C does not have classes makes the API quite different from how one would organize a Python API.

Wrapper libraries (such as py-bitcoinkernel) hide this "awkwardness" and expose a much more concise, Pythonic interface. To give maximum insight into the bitcoinkernel API, we will use the raw API in this workshop, while also offering a wrapped/ version using the py-bitcoinkernel library to highlight the difference. The wrapped version can be used as a guideline, too.

Both versions use shared code from the common/ library, which you shouldn't have to modify in this workshop.

Prerequisites

• Python 3.10 or later
• A Bitcoin Core datadir of the chain you are interested in. For this workshop, signet or mainnet are recommended. Because bitcoind requires exclusive access to the datadir, it is recommended you copy the blocks/ and chainstate/ directories to a separate directory for this workshop.
• py-bitcoinkernel and bitcoinkernel are dependencies of this project, and are installed automatically when you install the python package. Please refer to the py-bitcoinkernel installation instructions for more information.

Installation

cd python
python -m venv .venv
source .venv/bin/activate
pip install -e . -v

Running the workshop

1. Complete the code in the ./src/raw/main.py file.
2. Run the application (see args.py for more information on which arguments are available), as e.g.:

   raw --start_height=-10 --datadir=/tmp/kernel-workshop

3. If the application runs successfully, you should see a block_frequencies.json file in the data/op_code/frequency/ directory, containing the frequency of each TapScript OP_CODE in the specified blocks.
4. Optionally, visualize the results with the frontend.

[!NOTE] The solutions can be found in the main.py file in the solutions branch.