py-geth

Python wrapper around running geth as a subprocess

System Dependency

This library requires the geth executable to be present.

If managing your own bundled version of geth, set the path to the binary using the GETH_BINARY environment variable.

Installation

Installation

python -m pip install py-geth

Quickstart

To run geth connected to the mainnet

>>> from geth import LiveGethProcess
>>> geth = LiveGethProcess()
>>> geth.start()

Or a private local chain for testing. These require you to give them a name.

>>> from geth import DevGethProcess
>>> geth = DevGethProcess('testing')
>>> geth.start()

By default the DevGethProcess sets up test chains in the default datadir used by geth. If you would like to change the location for these test chains, you can specify an alternative base_dir.

>>> geth = DevGethProcess('testing', '/tmp/some-other-base-dir/')
>>> geth.start()

Each instance has a few convenient properties.

>>> geth.data_dir
"~/.ethereum"
>>> geth.rpc_port
8545
>>> geth.ipc_path
"~/.ethereum/geth.ipc"
>>> geth.accounts
['0xd3cda913deb6f67967b99d67acdfa1712c293601']
>>> geth.is_alive
False
>>> geth.is_running
False
>>> geth.is_stopped
False
>>> geth.start()
>>> geth.is_alive
True  # indicates that the subprocess hasn't exited
>>> geth.is_running
True  # indicates that `start()` has been called (but `stop()` hasn't)
>>> geth.is_stopped
False
>>> geth.stop()
>>> geth.is_alive
False
>>> geth.is_running
False
>>> geth.is_stopped
True

When testing it can be nice to see the logging output produced by the geth process. py-geth provides a mixin class that can be used to log the stdout and stderr output to a logfile.

>>> from geth import LoggingMixin, DevGethProcess
>>> class MyGeth(LoggingMixin, DevGethProcess):
...     pass
>>> geth = MyGeth()
>>> geth.start()

All logs will be written to logfiles in ./logs/ in the current directory.

The underlying geth process can take additional time to open the RPC or IPC connections, as well as to start mining if it needs to generate the DAG. You can use the following interfaces to query whether these are ready.

>>> geth.is_rpc_ready
True
>>> geth.wait_for_rpc(timeout=30)  # wait up to 30 seconds for the RPC connection to open
>>> geth.is_ipc_ready
True
>>> geth.wait_for_ipc(timeout=30)  # wait up to 30 seconds for the IPC socket to open
>>> geth.is_dag_generated
True
>>> geth.is_mining
True
>>> geth.wait_for_dag(timeout=600)  # wait up to 10 minutes for the DAG to generate.

The DAG functionality currently only applies to the DAG for epoch 0.

Installing specific versions of geth

This feature is experimental and subject to breaking changes.

Versions of geth dating back to v1.11.0 can be installed using py-geth. See install.py for the current list of supported versions.

Installation can be done via the command line:

$ python -m geth.install v1.13.4

Or from python using the install_geth function.

>>> from geth import install_geth
>>> install_geth('v1.13.4')

The installed binary can be found in the $HOME/.py-geth directory, under your home directory. The v1.13.4 binary would be located at $HOME/.py-geth/geth-v1.13.4/bin/geth.

About DevGethProcess

The DevGethProcess is designed to facilitate testing. In that regard, it is preconfigured as follows.

• A single account is created and allocated 1 billion ether.
• All APIs are enabled on both rpc and ipc interfaces.
• Account 0 is unlocked
• Networking is configured to not look for or connect to any peers.
• The networkid of 1234 is used.
• Verbosity is set to 5 (DEBUG)
• Mining is enabled with a single thread.
• The RPC interface tries to bind to 8545 but will find an open port if this port is not available.
• The DevP2P interface tries to bind to 30303 but will find an open port if this port is not available.

Gotchas

If you are running with mining enabled, which is default for DevGethProcess, then you will likely need to generate the DAG manually. If you do not, then it will auto-generate the first time you run the process and this takes a while.

To generate it manually:

$ geth makedag 0 ~/.ethash

This is especially important in CI environments like Travis-CI where your process will likely timeout during generation.

Development

Clone the repository:

$ git clone git@github.com:ethereum/py-geth.git

Next, run the following from the newly-created py-geth directory:

$ python -m pip install -e ".[dev]"

Running the tests

You can run the tests with:

pytest tests

Developer Setup

If you would like to hack on py-geth, please check out the Snake Charmers Tactical Manual for information on how we do:

• Testing
• Pull Requests
• Documentation

We use pre-commit to maintain consistent code style. Once installed, it will run automatically with every commit. You can also run it manually with make lint. If you need to make a commit that skips the pre-commit checks, you can do so with git commit --no-verify.

Development Environment Setup

You can set up your dev environment with:

git clone git@github.com:ethereum/py-geth.git
cd py-geth
virtualenv -p python3 venv
. venv/bin/activate
python -m pip install -e ".[dev]"
pre-commit install

Release setup

To release a new version:

make release bump=$$VERSION_PART_TO_BUMP$$

How to bumpversion

The version format for this repo is {major}.{minor}.{patch} for stable, and {major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta).

To issue the next version in line, specify which part to bump, like make release bump=minor or make release bump=devnum. This is typically done from the master branch, except when releasing a beta (in which case the beta is released from master, and the previous stable branch is released from said branch).

If you are in a beta version, make release bump=stage will switch to a stable.

To issue an unstable version when the current version is stable, specify the new version explicitly, like make release bump="--new-version 4.0.0-alpha.1 devnum"

Adding Support For New Geth Versions

There is an automation script to facilitate adding support for new geth versions: update_geth.py

To add support for a geth version, run the following line from the py-geth directory, substituting the version for the one you wish to add support for. Note that the v in the versioning is optional.

$ python update_geth.py v1_10_9

To introduce support for more than one version, pass in the versions in increasing order, ending with the latest version.

$ python update_geth.py v1_10_7 v1_10_8 v1_10_9

Always review your changes before committing as something may cause this existing pattern to change at some point. It is best to compare the git difference with a previous commit that introduced support for a new geth version to make sure everything looks good.