e2e: add elect command test

e2e/ctl_v3_elect_test.go

@@ -0,0 +1,113 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package e2e
+
+import (
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/coreos/etcd/pkg/expect"
+)
+
+func TestCtlV3Elect(t *testing.T) { testCtl(t, testElect) }
+
+func testElect(cx ctlCtx) {
+	name := "a"
+
+	holder, ch, err := ctlV3Elect(cx, name, "p1")
+	if err != nil {
+		cx.t.Fatal(err)
+	}
+
+	l1 := ""
+	select {
+	case <-time.After(2 * time.Second):
+		cx.t.Fatalf("timed out electing")
+	case l1 = <-ch:
+		if !strings.HasPrefix(l1, name) {
+			cx.t.Errorf("got %q, expected %q prefix", l1, name)
+		}
+	}
+
+	// blocked process that won't win the election
+	blocked, ch, err := ctlV3Elect(cx, name, "p2")
+	if err != nil {
+		cx.t.Fatal(err)
+	}
+	select {
+	case <-time.After(100 * time.Millisecond):
+	case <-ch:
+		cx.t.Fatalf("should block")
+	}
+
+	// overlap with a blocker that will win the election
+	blockAcquire, ch, err := ctlV3Elect(cx, name, "p2")
+	if err != nil {
+		cx.t.Fatal(err)
+	}
+	defer blockAcquire.Stop()
+	select {
+	case <-time.After(100 * time.Millisecond):
+	case <-ch:
+		cx.t.Fatalf("should block")
+	}
+
+	// kill blocked process with clean shutdown
+	if err = blocked.Signal(os.Interrupt); err != nil {
+		cx.t.Fatal(err)
+	}
+	if err = blocked.Close(); err != nil {
+		cx.t.Fatal(err)
+	}
+
+	// kill the holder with clean shutdown
+	if err = holder.Signal(os.Interrupt); err != nil {
+		cx.t.Fatal(err)
+	}
+	if err = holder.Close(); err != nil {
+		cx.t.Fatal(err)
+	}
+
+	// blockAcquire should win the election
+	select {
+	case <-time.After(time.Second):
+		cx.t.Fatalf("timed out from waiting to holding")
+	case l2 := <-ch:
+		if l1 == l2 || !strings.HasPrefix(l2, name) {
+			cx.t.Fatalf("expected different elect name, got l1=%q, l2=%q", l1, l2)
+		}
+	}
+}
+
+// ctlV3Elect creates a elect process with a channel listening for when it wins the election.
+func ctlV3Elect(cx ctlCtx, name, proposal string) (*expect.ExpectProcess, <-chan string, error) {
+	cmdArgs := append(cx.PrefixArgs(), "elect", name, proposal)
+	proc, err := spawnCmd(cmdArgs)
+	outc := make(chan string, 1)
+	if err != nil {
+		close(outc)
+		return proc, outc, err
+	}
+	go func() {
+		s, xerr := proc.ExpectFunc(func(string) bool { return true })
+		if xerr != nil {
+			cx.t.Errorf("expect failed (%v)", xerr)
+		}
+		outc <- s
+	}()
+	return proc, outc, err
+}