PyGeth

Python wrapper around running geth as a subprocess

Dependency

This library requires the geth executable to be present.

Quickstart

Installation

pip install py-geth

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_ready
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.

Aboutn 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.