elixxir/comms

This library implements functionality for communications operations in the xx network system.

How to run tests

First, make sure dependencies are installed into the vendor folder by running glide up. Then, in the project directory, run go test ./....

If what you're working on requires you to change other repos, you can remove the other repo from the vendor folder and Go's build tools will look for those packages in your Go path instead. Knowing which dependencies to remove can be really helpful if you're changing a lot of repos at once.

If glide isn't working and you don't know why, try removing glide.lock and ~/.glide to brutally cleanse the cache.

Regenerate Protobuf File

First install the protobuf compiler or update by following the instructions in Installing Protocol Buffer Compiler below.

Use the following command to compile a protocol buffer.

protoc -I. -I../vendor --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative *.proto

• This command must be run from the directory containing the .proto file being compiled.
• The -I flag specifies where to find imports used by the .proto file and may need to be modified or removed to suit the .proto file being compiled.\
  • 💡 Note: Note: If you are importing a file from the vendor directory, ensure that you have the correct version by running go mod vendor.
• If there is more than one proto file in the directory, replace *.proto with the file’s name.
• If the .proto file does not use gRPC, then the --go-grpc_out and --go-grpc_opt can be excluded.

Repository Organization

This repository is organized into 4 key folders:

1. mixmessages - contains the gRPC proto spec file and the file generated from that, along with any future shared helper functionality.
2. client - client functions for proper cmix clients.
3. node - gRPC endpoints hosted by cMix servers.
4. gateway - gateway endpoints and functions

Note that gateway and node are organized similarly. The endpoints.go file contains gRPC endpoint implementations, and the handler.go file contains the handler interface used by the endpoint implementations as well as the implementation struct.

Adding Network Endpoints

To add an endpoint, you need to make changes to handler.go and endpoint.go. You will also need to add a client function to call your new endpoint in the repo where the client is implemented.

handler.go:

1. Add your function to the interface.
2. Add it to the implementationFunctions struct.
3. Add the "Unimplemented warning" version of the function to NewImplementation()
4. Add the wrapper call to s.Functions.FUNCNAME(...) at the bottom to implement the interface for Implementation struct.

endpoint.go:

1. Add the gRPC implementation which calls the function through the handler.

Client Function:

1. Implement the client call either via a new module or an existing module. It should go in the location where the module is the client (i.e., if the node calls to the gateway, it goes in node)

Installing Protocol Buffer Compiler

This guide describes how to install the required dependencies to compile .proto files to Go.

Before following the instructions below, be sure to remove all old versions of protoc. If your previous protoc-gen-go file is not installed in your Go bin directory, it will also need to be removed.

If you have followed this guide previously when installing protoc and need to update, you can simply follow the instructions below. No uninstallation or removal is necessary.

To compile a protocol buffer, you need the protocol buffer compiler protoc along with two plugins protoc-gen-go and protoc-gen-go-grpc. Make sure you use the correct versions as listed below.

1. Download the correct release of protoc from the release page or use the link from the table above to get the download for your OS.

   wget https://github.com/protocolbuffers/protobuf/releases/download/v3.21.9/protoc-3.21.9-linux-x86_64.zip

2. Extract the files to a folder, such as $HOME/.local.

   unzip protoc-3.21.9-linux-x86_64.zip -d $HOME/.local

3. Add the selected directory to your environment’s PATH variable, make sure to include it in your .profile or .bashrc file. Also, include your go bin directory ($GOPATH/bin or $GOBIN) if it is not already included.

   export PATH="$PATH:$HOME/.local/bin:$GOPATH/bin"

   💡 Note: Make sure you update your configuration file once done with source .profile.

4. Now check that protoc is installed with the correct version by running the following command.

   protoc --version

   Which prints the current version

   libprotoc 3.21.9

5. Next, download protoc-gen-go and protoc-gen-go-grpc using the version found in the table above.

   go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
   go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2

6. Check that protoc-gen-go is installed with the correct version.

   protoc-gen-go --version
   protoc-gen-go v1.28.1

7. Check that protoc-gen-go-grpc is installed with the correct version.

   protoc-gen-go-grpc --version
   protoc-gen-go-grpc 1.2.0