66 lines
2.3 KiB
Markdown
66 lines
2.3 KiB
Markdown
# How to write a Python gRPC client for the Lightning Network Daemon #
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This section enumerates what you need to do to write a client that communicates
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with lnd in Python.
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Lnd uses the gRPC protocol for communication with clients like lncli. gRPC is
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based on protocol buffers and as such, you will need to compile the lnd proto
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file in Python before you can use it to communicate with lnd. The following are
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the steps to take.
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* Create a virtual environment for your project
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```
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$ virtualenv lnd
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```
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* Activate the virtual environment
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```
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$ source lnd/bin/activate
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```
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* Install dependencies (googleapis-common-protos is required due to the use of
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google/api/annotations.proto)
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```
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(lnd)$ pip install grpcio grpcio-tools googleapis-common-protos
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```
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* Clone the google api's repository (required due to the use of
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google/api/annotations.proto)
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```
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(lnd)$ git clone https://github.com/googleapis/googleapis.git
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```
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* Copy the lnd rpc.proto file (you'll find this in lnrpc/rpc.proto) or just
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download it
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```
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(lnd)$ curl -o rpc.proto -s https://raw.githubusercontent.com/lightningnetwork/lnd/master/lnrpc/rpc.proto
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```
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* Compile the proto file
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```
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(lnd)$ python -m grpc_tools.protoc --proto_path=googleapis:. --python_out=. --grpc_python_out=. rpc.proto
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```
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After following these steps, two files `rpc_pb2.py` and `rpc_pb2_grpc.py` will
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be generated. These files will be imported in your project while writing your
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clients. Here's an example of a simple client that was built using these.
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```python
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# python-based lnd client to retrieve and display wallet balance
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import grpc
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import rpc_pb2 as ln
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import rpc_pb2_grpc as lnrpc
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channel = grpc.insecure_channel('localhost:10009')
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stub = lnrpc.LightningStub(channel)
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response = stub.WalletBalance(ln.WalletBalanceRequest(witness_only=True))
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print(response.balance)
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```
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With the above, you should have all the `lnd` related `gRPC` dependencies
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installed locally into your virtual environment. In order to get up to speed
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with `protofbuf` usage from Python, see [this official `protobuf` tutorial for
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Python](https://developers.google.com/protocol-buffers/docs/pythontutorial).
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Additionally, [this official gRPC
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resource](http://www.grpc.io/docs/tutorials/basic/python.html) details how to
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drive `gRPC` from Python including the basics of making RPC calls, streaming
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RPC's (bi-directional and uni-directional), etc.
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