From 1ee25513255d0657c67e6ccb2a14f3697ed05c73 Mon Sep 17 00:00:00 2001
From: Ettore Di Giacinto <mudler@gentoo.org>
Date: Sun, 3 Nov 2019 12:03:26 +0100
Subject: [PATCH] Consume a context when sourcing ebuild in parallel

---
 pkg/tree/builder/gentoo/gentoo.go | 34 ++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/pkg/tree/builder/gentoo/gentoo.go b/pkg/tree/builder/gentoo/gentoo.go
index fa3c8cd3..5981611d 100644
--- a/pkg/tree/builder/gentoo/gentoo.go
+++ b/pkg/tree/builder/gentoo/gentoo.go
@@ -19,11 +19,13 @@ package gentoo
 // https://gist.github.com/adnaan/6ca68c7985c6f851def3
 
 import (
+	"context"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	. "github.com/mudler/luet/pkg/logger"
 	tree "github.com/mudler/luet/pkg/tree"
@@ -74,17 +76,25 @@ func (gb *GentooBuilder) scanEbuild(path string, t pkg.Tree) error {
 	return nil
 }
 
-func (gb *GentooBuilder) worker(i int, wg *sync.WaitGroup, s <-chan string, t pkg.Tree) {
+func (gb *GentooBuilder) worker(ctx context.Context, i int, wg *sync.WaitGroup, s <-chan string, t pkg.Tree) {
 	defer wg.Done()
-
-	for path := range s {
-		Info("#"+strconv.Itoa(i), "parsing", path)
-		err := gb.scanEbuild(path, t)
-		if err != nil {
-			Error(path, ":", err.Error())
+	for {
+		select {
+		case <-ctx.Done():
+			Info("Worker is done!")
+			return
+		case path, ok := <-s:
+			if !ok {
+				// Channel closed
+				return
+			}
+			Info("#"+strconv.Itoa(i), "parsing", path)
+			err := gb.scanEbuild(path, t)
+			if err != nil {
+				Error(path, ":", err.Error())
+			}
 		}
 	}
-
 }
 
 func (gb *GentooBuilder) Generate(dir string) (pkg.Tree, error) {
@@ -96,6 +106,8 @@ func (gb *GentooBuilder) Generate(dir string) (pkg.Tree, error) {
 	Spinner(27)
 	defer SpinnerStop()
 	tree := &GentooTree{DefaultTree: &tree.DefaultTree{Packages: pkg.NewInMemoryDatabase(false)}}
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
 
 	//tree := &GentooTree{DefaultTree: &tree.DefaultTree{Packages: pkg.NewBoltDatabase(tmpfile.Name())}}
 	Debug("Concurrency", gb.Concurrency)
@@ -103,7 +115,7 @@ func (gb *GentooBuilder) Generate(dir string) (pkg.Tree, error) {
 	var wg = new(sync.WaitGroup)
 	for i := 0; i < gb.Concurrency; i++ {
 		wg.Add(1)
-		go gb.worker(i, wg, toScan, tree)
+		go gb.worker(ctx, i, wg, toScan, tree)
 	}
 
 	// TODO: Handle cleaning after? Cleanup implemented in GetPackageSet().Clean()
@@ -121,9 +133,11 @@ func (gb *GentooBuilder) Generate(dir string) (pkg.Tree, error) {
 		return nil
 	})
 
-	close(toScan)
 	Debug("Waiting for goroutines to finish")
+	close(toScan)
+
 	wg.Wait() // FIXME: With BoltDB as backend goroutines timeouts and deadlocks
+
 	if err != nil {
 		return tree, err
 	}