README.md

gromise

A library to execute goroutines like Promise.allSettled in JavaScript, make some scenarios (e.g. BFF data aggregation) easier.

Usage

import (
    "errors"
    "github.com/rexskz/gromise"
)

// 1. define a list of functions
fns := []gromise.Executor{
    func() (interface{}, error) {
        // business logic that may cause lots of time
        return data, nil
    },
    func() (interface{}, error) {
        // a function that can return error
        return nil, errors.New("this is an error")
    },
    func() (interface{}, error) {
        // panic will be converted to error
        panic("fatal error")
    },
    // ...other functions
}

// 2. execute all functions concurrently and block until all
// functions are finished, throw error, panic, or timeout
timeoutMs := 1000
results, err := gromise.New(timeoutMs).AllSettled(fns).Await()

// 3. the results (if not timeout) will be like:
assert.Equal(t, results, []*gromise.AllSettledValue{
    {
        Status: gromise.StatusFulfilled,
        Value:  data,
    },
    {
        Status: gromise.StatusRejected,
        Reason: errors.New("this is an error"),
    },
    {
        Status: gromise.StatusRejected,
        Reason: errors.New("fatal error"),
    },
})

// 4. if timeout, the error will be:
assert.Equal(t, err, gromise.ErrTimeout)

Test & Coverage

./scripts/run_tests.sh

You can find the coverage report in ./coverage/index.html.

Why It's Useful

Sometimes we need to execute a list of functions concurrently and block until all functions are finished, e.g. BFF data aggregation. In JavaScript, we can use Promise.all to achieve this, but in Go, we have to use sync.WaitGroup or chan, and handle the panic manually, which is not so convenient. This library is to make this scenario easier.

License

MIT