Examples

An example microservice is located in the examples/pinger folder. This includes only the .proto definition file and a Golang generate.go file.

To generate the microservice, run:

cd examples/pinger
go generate generate.go

Tests are generated for all client interface functions; to run these, do:

go test ./...

(Note the tests fail with a TODO: Implement test... message)

Clean any of the example folders (i.e. remove all generated files) with:

git clean -xfd

Install stategen

go get https://github.com/thecodedproject/msgen/stategen

Notes on protoc and importing custom proto message definitions

Proto definitions are extensible, with messages (and other proto gubbins) able to imported into another proto file using the import keyword, e.g.

import "google/protobuf/timestamp.proto";

The protoc compiler will search for these imports in (at least) these locations:

1. Looking in the relative path ../include from the protoc executable.

This doesn't seem to be documented anywhere, but seems reasoanable - on a typical unix system protoc is installed in some usr/bin folder with the common proto files being installed into usr/include (e.g. usr/include/google/protobuf

2. By specifying --proto_path=PATH argument when calling protoc (can be be specified multiple times), e.g:

> protoc --proto_path='som/path' --proto_path='some/other/path'

3. The currenct working directory

This has implications for finding (and automatically generting code which calls) the conversion functions for these imported proto message types:

• The proto files themselves will define a go_package option e.g.

  option go_package = "github.com/golang/protobuf/ptypes/timestamp";

which shows where the corresponding golang definitions for these types should be imported from (this needs to be an importable golang path)

• (TODO - 20221231) Still need figure out how this is to be solved - see one of a few options:
  • (probably easiest) Specify specific go packages which contain conversion functions;
    • scan these pacakges for all the available conversion functions
    • A conversion function will have a specific signature (i.e. XToProto(X) pb.XMessage and XFromProto(pb.XMessage) X)
    • Check we have all the reuqired conversion functions
    • If we don't then raise an error