lnd/mobile

Building mobile libraries

Prerequisites

protoc

Install the dependencies for generating protobuf definitions as stated in lnrpc docs

gomobile

Follow gomobile in order to install gomobile and dependencies.

Remember to run gomobile init (otherwise the lnd build might just hang).

Note that gomobile only supports building projects from GOPATH at this point.

falafel

Install falafel:

⛰  go get -u -v github.com/lightninglabs/falafel

Building lnd for iOS

⛰  make ios

Building lnd for Android

⛰  make android

make mobile will build both iOS and Android libs.

Libraries

After the build has succeeded, the libraries will be found in mobile/build/ios/Lndmobile.framework and mobile/build/android/Lndmobile.aar. Reference your platforms' SDK documentation for how to add the library to your project.

Generating proto definitions for your language.

In order to call the methods in the generated library, the serialized proto for the given RPC call must be provided. Similarly, the response will be a serialized proto.

iOS

In order to generate protobuf definitions for iOS, add --swift_out=. to the first protoc invocation found in gen_protos.sh.

Then, some changes to Dockerfile need to be done in order to use the Swift protobuf plugin with protoc:

1. Replace the base image with FROM swift:focal so that Swift can be used.
2. clang-format='1:7.0*' is unavailable in Ubuntu Focal. Change that to clang-format='1:10.0*.
3. On the next line, install Go and set the environment variables by adding the following commands:

RUN apt-get install -y wget \
    && wget -c https://golang.org/dl/go1.17.2.linux-amd64.tar.gz -O - \
    | tar -xz -C /usr/local
ENV GOPATH=/go
ENV PATH=$PATH:/usr/local/go/bin:/go/bin

4. At the end of the file, just above CMD, add the following RUN command. This will download and compile the latest tagged release of Swift protobuf.

RUN git clone https://github.com/apple/swift-protobuf.git \
&& cd swift-protobuf \ 
&& git checkout $(git describe --tags --abbrev=0) \
&& swift build -c release \
&& mv .build/release/protoc-gen-swift /bin

Finally, run make rpc.

Android

In order to generate protobuf definitions for Android, add --java_out=. to the first protoc invocation found in gen_protos.sh. Then, run make rpc.

Options

Similar to lnd, subservers can be conditionally compiled with the build by setting the tags argument:

⛰  make ios

To support subservers that have APIs with name conflicts, pass the "prefix" flag. This will add the subserver name as a prefix to each method name:

⛰  make ios prefix=1

API docs

TODO(halseth)