add simple FindProvs support

Author: Kubuxu

shell.go

@@ -355,17 +355,22 @@ func (s *Shell) FindProvs(ctx context.Context, cid string) (<-chan pstore.PeerIn
 	outchan := make(chan pstore.PeerInfo, 4)
 
 	go func() {
+		defer cancel()
+
 		var n notif.QueryEvent
 		scanner := bufio.NewScanner(resp.Output)
 		for scanner.Scan() {
 			json.Unmarshal(scanner.Bytes(), &n)
 			if n.Type == notif.Provider {
 				for _, p := range n.Responses {
-					outchan <- *p
+					select {
+					case outchan <- *p:
+					case <-ctx.Done():
+						return
+					}
 				}
 			}
 		}
-		cancel()
 	}()
 
 	go func() {

shell_test.go

@@ -2,6 +2,7 @@ package shell
 
 import (
 	"bytes"
+	"context"
 	"crypto/md5"
 	"fmt"
 	"io"
@@ -167,3 +168,18 @@ func TestPubSub(t *testing.T) {
 
 	is.Nil(sub.Cancel())
 }
+
+func TestFindProvs(t *testing.T) {
+	is := is.New(t)
+	s := NewShell(shellUrl)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	c, err := s.FindProvs(ctx, "Qme1g4e3m2SmdiSGGU3vSWmUStwUjc5oECnEriaK9Xa1HU")
+	is.Nil(err)
+
+	p := <-c
+	t.Logf("prov: %s", p)
+	is.NotNil(p)
+	is.NotNil(p.ID)
+}