examples

Go: OpenConfg 1.0 Examples

Prerequisites

• Go

For installation instructions, see Go’s Getting Started guide.

• Protocol buffer compiler (protoc), version 3.

For installation instructions, see Protocol Buffer Compiler Installation.

• Go plugins for the protocol compiler:

  1. Install the protocol compiler plugins for Go and ProtoConfig using the following commands:

  export GO111MODULE=on  # Enable module mode
  go get google.golang.org/protobuf/cmd/protoc-gen-go \
    github.com/openproto/protoconfig/go/protoc-gen-go-protoconfig
  

  1. Update your PATH so that the protoc compiler can find the plugins:

  export PATH="$PATH:$(go env GOPATH)/bin
  

Steps

1. Start by reading example application Configuration Proto Definition complainant with ProtoConfig 1.0 (from repo root): proto/examples/helloworld/v1/helloworld.proto

This file is just .proto with a couple of options from few extensions:

• protoconfig defined in proto/protoconfig/v1/extensions.proto is an ProtoConfig 1.0 extension which adds optional context for given data fields like: required hidden default and allows to add metadata that indicates the entry point(s) for the configuration.
• kingpin defined in proto/go/kingpinv2/v1/extensions.proto which adds Go, kingpin specific options allowing even more Go or kingpin library specific context like custom types (existing file, regexp, IP) etc!

The power of ProtoConfig 1.0 comes from protobuf superpowers: Those options are fully ignored if your protoc does not have plugins supporting them (for example you generate data structures for C++ or Java!). This allows ultimate extensibility.

1. This example has already generated Go code from this helloworld application Configuration Proto Definition, and you can see it go/examples/helloworld/helloworld.pb.go and go/examples/helloworld/helloworld_protoconfig.pb.go. Since it's generated code, it's not readable much. Check go.dev instead! (It's go code after all and supports godoc!)

What you see is the protobuf Go code that allows to marshal and unmarshal filled types in to ProtoConfig 1.0 (and proto) compliant encoding.

1. Change directory to our quick start example directory for Go cd go/examples/helloworld

2. In this directory, on top of generated Go code for helloworld Configuration Proto Definition we see a couple of directories:

• ./configurable is an ProtoConfig 1.0 compliant helloword application that just allows ProtoConfig for configuration.
• ./configurable-kingpinv2 is an ProtoConfig 1.0 compliant helloword application that allows ProtoConfig as well as standard POSIX flags (that were manually implemented based on kingpin library ) for configuration.
• ./configurable-kingpinv2-gen is an ProtoConfig 1.0 compliant helloword application that allows ProtoConfig as well as standard POSIX flags that were generated thanks to ../kingpinv2/ extension.
• ./configurator is helloworld application client that configures (by executing it in another process) in couple different ways in order to get (really!) Hello my world for "Alt C" in 2077 year! string output.

1. Feel free to run ./configurable-kingpinv2 with any parameters you want. Check all flags via go run ./configurable-kingpinv2 --help Executable will execute all as Configuration Proto Definition defines and help specifies. For example you can run:

go run ./configurable-kingpinv2 hello --world="my" --year=2077 --name="Alt C" --lang=ENGLISH --add-really

But you can also use ProtoConfig 1.0 convention!:

go run ./configurable-kingpinv2 --protoconfigv1='{"hello": {"name": "Alt C", "year": 2077, "world": "my", "add_really": true}}'

All the above should print (really!) Hello my world for "Alt C" in 2077 year!

1. Run configurator to check if all applications returns expected message by running: go run ./configurator

2. Read ./configurator to check all different ways to configure helloworld configurable with and without ProtoConfig 1.0!

Updating Configuration Proto Definition

TBD (tl;dr: make proto)