rutina

Package Rutina (russian "рутина" - ordinary boring everyday work) is routine orchestrator for your application.

It seems like https://godoc.org/golang.org/x/sync/errgroup with some different:

1) propagates context to every routines. So routine can check if context stopped (ctx.Done()). 2) has flexible run/stop policy. i.e. one routine restarts when it fails (useful on daemons) but if fails another - all routines will be cancelled 3) already has optional signal handler ListenOsSignals()

When it need?

Usually, when your program consists of several routines (i.e.: http server, metrics server and os signals subscriber) and you want to stop all routines when one of them ends (i.e.: by TERM os signal in signal subscriber).

Usage

New instance

r := rutina.New()

or with optional mixins (see below):

r := rutina.New(...Mixins)

or

r.With(...Mixins)

Start new routine

r.Go(func (ctx context.Context) error {
    ...do something...
}, ...runOptions)

Available options of run policy:

ShutdownIfFail - Shutdown all routines if this routine fails
RestartIfFail - Restart this routine if it fail
DoNothingIfFail - Do nothing just stop this routine if it fail
ShutdownIfDone - Shutdown all routines if this routine done without errors
RestartIfDone - Restart if this routine done without errors
DoNothingIfDone - Do nothing if this routine done without errors

Default policy:

ShutdownIfFail && ShutdownIfDone

(just like errgroup)

Example of run policies

r.Go(func(ctx context.Context) error {
    // If this routine produce no error - it just restarts
    // If it returns error - all other routines will shutdown (because context cancels)
}, rutina.RestartIfDone, rutina.ShutdownIfFail)

r.Go(func(ctx context.Context) error {
    // If this routine produce no error - it just completes
    // If it returns error - all other routines will shutdown (because context cancels)
}, rutina.DoNothingIfDone, rutina.ShutdownIfFail)

r.Go(func(ctx context.Context) error {
    // If this routine produce no error - all other routines will shutdown (because context cancels)
    // If it returns error - it will be restarted
}, rutina.RestartIfFail)

r.Go(func(ctx context.Context) error {
    // If this routine stopped by any case - all other routines will shutdown (because context cancels)
}, rutina.ShutdownIfDone)

r.ListenOsSignals() // Shutdown all routines by OS signal

Wait routines to complete

err := r.Wait()

Here err = error that shutdowns all routines (may be will be changed at future)

Get errors channel

err := <- r.Errors()

Disabled by default. Use r.With(rutina.WithErrChan()) to turn on.

Mixins

Usage

r := rutina.New(mixin1, mixin2, ...)

or

r := rutina.New()
r = r.With(mixin1, mixin2, ...) // Returns new instance of Rutina!

Logger

r = r.With(rutina.WithStdLogger())

or

r = r.With(rutina.WithLogger(logger log.Logger))

Sets standard or custom logger. By default there is no logger.

Custom context

r = r.With(rutina.WithContext(ctx context.Context))
````

Propagates your own context to Rutina. By default it use own context. 

### Enable errors channel

```go
r = r.With(rutina.WithErrChan())
...
err := <- r.Errors()

Turn on errors channel

Example

HTTP server with graceful shutdown example/http_server.go

Different run policies example/policies.go