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https://github.com/autom8ter/machine

Machine is a zero dependency library for highly concurrent Go applications. It is inspired by errgroup.Group with extra bells & whistles
https://github.com/autom8ter/machine

concurrency cron go goroutine streaming

Last synced: 11 days ago
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Machine is a zero dependency library for highly concurrent Go applications. It is inspired by errgroup.Group with extra bells & whistles

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README

        

# Machine [![GoDoc](https://godoc.org/github.com/autom8ter/machine/v4?status.svg)](https://godoc.org/github.com/autom8ter/machine/v4)

![concurrency](images/concurrency.jpg)

`import "github.com/autom8ter/machine/v4"`

[Machine](https://pkg.go.dev/github.com/autom8ter/machine/v4#Machine) is a zero dependency library for highly concurrent Go applications.
It is inspired by [`errgroup`](https://pkg.go.dev/golang.org/x/sync/errgroup)`.`[`Group`](https://pkg.go.dev/golang.org/x/sync/errgroup#Group) with extra bells & whistles:
- In memory Publish Subscribe for asynchronously broadcasting & consuming messages in memory
- Asynchronous worker groups similar to errgroup.Group
- Throttled max active goroutine count
- Asynchronous error handling(see `WithErrorHandler` to override default error handler)
- Asynchronous cron jobs- `Cron()`

## Use Cases

[Machine](https://pkg.go.dev/github.com/autom8ter/machine#Machine) is meant to be completely agnostic and dependency free- its use cases are expected to be emergent.
Really, it can be used **anywhere** goroutines are used.

Highly concurrent and/or asynchronous applications include:

- gRPC streaming servers

- websocket servers

- pubsub servers

- reverse proxies

- cron jobs

- custom database/cache

- ETL pipelines

- log sink

- filesystem walker

- code generation

```go
// Machine is an interface for highly asynchronous Go applications
type Machine interface {
// Publish synchronously publishes the Message
Publish(ctx context.Context, msg Message)
// Subscribe synchronously subscribes to messages on a given channel, executing the given HandlerFunc UNTIL the context cancels OR false is returned by the HandlerFunc.
// Glob matching IS supported for subscribing to multiple channels at once.
Subscribe(ctx context.Context, channel string, handler MessageHandlerFunc, opts ...SubscriptionOpt)
// Subscribers returns total number of subscribers to the given channel
Subscribers(channel string) int
// Channels returns the channel names that messages have been sent to
Channels() []string
// Go asynchronously executes the given Func
Go(ctx context.Context, fn Func)
// Cron asynchronously executes the given function on a timed interval UNTIL the context cancels OR false is returned by the CronFunc
Cron(ctx context.Context, interval time.Duration, fn CronFunc)
// Current returns the number of active jobs that are running concurrently
Current() int
// Wait blocks until all active async functions(Go, Cron) exit
Wait()
// Close blocks until all active routine's exit(calls Wait) then closes all active subscriptions
Close()
}
```

## Example

```go
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
var (
m = machine.New()
results []string
mu sync.RWMutex
)
defer m.Close()

m.Go(ctx, func(ctx context.Context) error {
m.Subscribe(ctx, "accounting.*", func(ctx context.Context, msg machine.Message) (bool, error) {
mu.Lock()
results = append(results, fmt.Sprintf("(%s) received msg: %v\n", msg.Channel, msg.Body))
mu.Unlock()
return true, nil
})
return nil
})
m.Go(ctx, func(ctx context.Context) error {
m.Subscribe(ctx, "engineering.*", func(ctx context.Context, msg machine.Message) (bool, error) {
mu.Lock()
results = append(results, fmt.Sprintf("(%s) received msg: %v\n", msg.Channel, msg.Body))
mu.Unlock()
return true, nil
})
return nil
})
m.Go(ctx, func(ctx context.Context) error {
m.Subscribe(ctx, "human_resources.*", func(ctx context.Context, msg machine.Message) (bool, error) {
mu.Lock()
results = append(results, fmt.Sprintf("(%s) received msg: %v\n", msg.Channel, msg.Body))
mu.Unlock()
return true, nil
})
return nil
})
m.Go(ctx, func(ctx context.Context) error {
m.Subscribe(ctx, "*", func(ctx context.Context, msg machine.Message) (bool, error) {
mu.Lock()
results = append(results, fmt.Sprintf("(%s) received msg: %v\n", msg.Channel, msg.Body))
mu.Unlock()
return true, nil
})
return nil
})
<-time.After(1 * time.Second)
m.Publish(ctx, machine.Message{
Channel: "human_resources.chat_room6",
Body: "hello world human resources",
})
m.Publish(ctx, machine.Message{
Channel: "accounting.chat_room2",
Body: "hello world accounting",
})
m.Publish(ctx, machine.Message{
Channel: "engineering.chat_room1",
Body: "hello world engineering",
})
m.Wait()
sort.Strings(results)
for _, res := range results {
fmt.Print(res)
}
// Output:
//(accounting.chat_room2) received msg: hello world accounting
//(accounting.chat_room2) received msg: hello world accounting
//(engineering.chat_room1) received msg: hello world engineering
//(engineering.chat_room1) received msg: hello world engineering
//(human_resources.chat_room6) received msg: hello world human resources
//(human_resources.chat_room6) received msg: hello world human resources
```

### Extended Examples

All examples are < 500 lines of code(excluding code generation)

- [gRPC Bidirectional Chat Stream Server](examples/README.md#grpc-bidirectional-chat-server)
- [Concurrent Cron Job Server](examples/README.md#concurrent-cron-server)
- [TCP Reverse Proxy](examples/README.md#tcp-reverse-proxy)