Rename lcProcess.Run to Append, add docs

License: MIT
Signed-off-by: Łukasz Magiera <magik6k@gmail.com>

core/node/helpers.go

@@ -6,6 +6,7 @@ import (
 	config "github.com/ipfs/go-ipfs-config"
 	uio "github.com/ipfs/go-unixfs/io"
 	"github.com/jbenet/goprocess"
+	"github.com/pkg/errors"
 	"go.uber.org/fx"
 )
 
@@ -31,15 +32,23 @@ type lcProcess struct {
 	Proc goprocess.Process
 }
 
-func (lp *lcProcess) Run(f goprocess.ProcessFunc) {
-	proc := make(chan goprocess.Process, 1)
+// Append wraps ProcessFunc into a goprocess, and appends it to the lifecycle
+func (lp *lcProcess) Append(f goprocess.ProcessFunc) {
+	// Hooks are guaranteed to run in sequence. If a hook fails to start, its
+	// OnStop won't be executed.
+	var proc goprocess.Process
+
 	lp.LC.Append(fx.Hook{
 		OnStart: func(ctx context.Context) error {
-			proc <- lp.Proc.Go(f)
+			proc = lp.Proc.Go(f)
 			return nil
 		},
 		OnStop: func(ctx context.Context) error {
-			return (<-proc).Close() // todo: respect ctx, somehow
+			if proc == nil { // Theoretically this shouldn't ever happen
+				return errors.New("lcProcess: proc was nil")
+			}
+
+			return proc.Close() // todo: respect ctx, somehow
 		},
 	})
 }

core/node/ipns.go

@@ -66,6 +66,6 @@ func IpnsRepublisher(lc lcProcess, cfg *config.Config, namesys namesys.NameSyste
 		repub.RecordLifetime = d
 	}
 
-	lc.Run(repub.Run)
+	lc.Append(repub.Run)
 	return nil
 }

go.mod

@@ -100,6 +100,7 @@ require (
 	github.com/multiformats/go-multibase v0.0.1
 	github.com/multiformats/go-multihash v0.0.1
 	github.com/opentracing/opentracing-go v1.0.2
+	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v0.9.2
 	github.com/syndtr/goleveldb v1.0.0
 	github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc