m: implement Run function, which glues together mcfg.Populate, mrun.Start, and mrun.Stop

m/m.go

@@ -5,7 +5,14 @@
 package m
 
 import (
+	"os"
+	"os/signal"
+
 	"github.com/mediocregopher/mediocre-go-lib/mcfg"
+	"github.com/mediocregopher/mediocre-go-lib/mctx"
+	"github.com/mediocregopher/mediocre-go-lib/merr"
+	"github.com/mediocregopher/mediocre-go-lib/mlog"
+	"github.com/mediocregopher/mediocre-go-lib/mrun"
 )
 
 // CfgSource returns an mcfg.Source which takes in configuration info from the
@@ -16,3 +23,34 @@ func CfgSource() mcfg.Source {
 		mcfg.SourceCLI{},
 	}
 }
+
+// TODO Create a function, `NewService() mctx.Context` which preloads the
+// context with log-level param. Will one day also add debug server. Problem
+// comes because mlog isn't quite designed right and setting log-level from
+// config won't propagate changes to child contexts which have already called
+// mlog.From.
+
+// Run performs the work of populating configuration parameters, triggering the
+// start event, waiting for an interrupt, and then triggering the stop event.
+// Run will block until the stop event is done. If any errors are encountered a
+// fatal is thrown.
+func Run(ctx mctx.Context) {
+	log := mlog.From(ctx)
+	if err := mcfg.Populate(ctx, CfgSource()); err != nil {
+		log.Fatal("error populating configuration", merr.KV(err))
+	} else if err := mrun.Start(ctx); err != nil {
+		log.Fatal("error triggering start event", merr.KV(err))
+	}
+
+	{
+		ch := make(chan os.Signal, 1)
+		signal.Notify(ch, os.Interrupt)
+		s := <-ch
+		log.Info("signal received, stopping", mlog.KV{"signal": s})
+	}
+
+	if err := mrun.Stop(ctx); err != nil {
+		log.Fatal("error triggering stop event", merr.KV(err))
+	}
+	log.Info("exiting process")
+}