Goodwill is a plugin for Walmart Labs Concord. It provides a way to write tasks in Go by providing a bridge to the Java runtime over GRPC.

Goodwill tasks are written in go files which have a build tag goodwill

In your project root, create a file named something like goodwill.go.

// +build goodwill

package main

import (
	"context"

	"go.justen.tech/goodwill/gw"
	"go.justen.tech/goodwill/gw/value"
)

// Each task is a function with the following signature
// The function name should be capitalized

// Both the ctx context.Context arg and the map[string]value.Value return are optional
// and may be omitted from the method signature

// Default Task, Says Hello
func Default(ctx context.Context, ts *gw.Task) (map[string]value.Value, error) {
	_ = ts.Log(ctx, "Hello, Goodwill!")
	return nil, nil
}

In your concord.yml, you can call the go code using the goodwill task.

configuration:
  dependencies:
    - mvn://tech.justen.concord:goodwill:0.7.1

flows:
  default:
    - task: goodwill

By default, goodwill installs Go and compiles the tasks on the Concord server. While the cost of this is amortized over the number of tasks you execute within a single flow, this added time and compilation on the Concord agent may be undesirable. In these cases, you can run goodwill yourself to pre-compile the tasks.

$ goodwill -os linux -arch amd64

If a goodwill.tasks binary exists in your concord payload, this will be used instead of compiling from your tasks source.

The goodwill task can take several optional in parameters.

• task: The name of the task to run. (default: Default)
• binary: The path to the pre-compiled goodwill tasks. (default: goodwill.tasks)
• debug: Enable debug logging for compilation. (default: false)

• goVersion: Set the version of Go to install. (Default: 1.22.3)
• goDockerImage: Override the image to use when building a goodwill flow in Docker (Default: golang:${goVersion})
• useDocker: Use a docker image to compile the goodwill binary.
• installGo: If compilation is required and go is not found, install it in the task workspace (Default: true)
• buildDir: Override the output directory for goodwill generated files. (default: .goodwill)'

• GOOS: Override the OS target of the concord agent instead of auto-detecting it.
• GOARCH: Override the OS Architecture of the target instead of auto-detecting it.
• GOPROXY: Set the GOPROXY environment variable
• GONOPROXY: Set the GONOPROXY environment variable
• GOPRIVATE: Set the GOPRIVATE environment variable
• GOSUMDB: Set the GOSUMDB environment variable
• GONOSUMDB: Set the GONOSUMDB environment variable

This project uses Mage to produce build artifacts and to run tests. Before building, you'll need to install Mage yourself.

git clone https://github.com/magefile/mage
cd mage
go run bootstrap.go

To build just the binary for your platform:

mage build

The binary will be in ./bin.

To build and package release files, including the Concord plugin, run:

mage package

The files will be placed in ./dist

To run End-to-End tests, you need to install OpenTofu and Docker.

mage e2e:test

This will bring a local Concord instance up in Docker, and make it available on http://localhost:8001 and run a few flows against the instance using Goodwill.