lnd.xprv/docs/grpc/python.md

How to write a Python gRPC client for the Lightning Network Daemon

This section enumerates what you need to do to write a client that communicates with lnd in Python.

Lnd uses the gRPC protocol for communication with clients like lncli. gRPC is based on protocol buffers and as such, you will need to compile the lnd proto file in Python before you can use it to communicate with lnd. The following are the steps to take.

• Create a virtual environment for your project

$ virtualenv lnd

• Activate the virtual environment

$ source lnd/bin/activate

• Install dependencies (googleapis-common-protos is required due to the use of google/api/annotations.proto)

(lnd)$ pip install grpcio grpcio-tools googleapis-common-protos

• Clone the google api's repository (required due to the use of google/api/annotations.proto)

(lnd)$ git clone https://github.com/googleapis/googleapis.git

• Copy the lnd rpc.proto file (you'll find this in lnrpc/rpc.proto) or just download it

(lnd)$ curl -o rpc.proto -s https://raw.githubusercontent.com/lightningnetwork/lnd/master/lnrpc/rpc.proto

• Compile the proto file

(lnd)$ python -m grpc_tools.protoc --proto_path=googleapis:. --python_out=. --grpc_python_out=. rpc.proto

After following these steps, two files rpc_pb2.py and rpc_pb2_grpc.py will be generated. These files will be imported in your project while writing your clients. Here's an example of a simple client that was built using these.

# python-based lnd client to retrieve and display wallet balance

import grpc

import rpc_pb2 as ln
import rpc_pb2_grpc as lnrpc

channel = grpc.insecure_channel('localhost:10009')
stub = lnrpc.LightningStub(channel)

response = stub.WalletBalance(ln.WalletBalanceRequest(witness_only=True))
print(response.balance)

With the above, you should have all the lnd related gRPC dependencies installed locally into your virtual environment. In order to get up to speed with protofbuf usage from Python, see this official protobuf tutorial for Python. Additionally, this official gRPC resource details how to drive gRPC from Python including the basics of making RPC calls, streaming RPC's (bi-directional and uni-directional), etc.