alertmanager/cluster/channel_test.go
stuart nelson 445fbdf1a8
gossip large messages via SendReliable (#1415)
* Gossip large messages via SendReliable

For messages beyond half of the maximum gossip
packet size, send the message to all peer nodes
via TCP.

The choice of "larger than half the max gossip
size" is relatively arbitrary. From brief testing,
the overhead from memberlist on a packet seemed to
only use ~3 of the available 1400 bytes, and most
gossip messages seem to be <<500 bytes.

* Add tests for oversized/normal message gossiping

* Make oversize metric names consistent

* Remove errant printf in test

* Correctly increment WaitGroup

* Add comment for OversizedMessage func

* Add metric for oversized messages dropped

Code was added to drop oversized messages if the
buffered channel they are sent on is full. This
is a good thing to surface as a metric.

* Add counter for total oversized messages sent

* Change full queue log level to debug

Was previously a warning, which isn't necessary
now that there is a metric tracking it.

Signed-off-by: stuart nelson <stuartnelson3@gmail.com>
2018-06-15 13:40:21 +02:00

90 lines
2.1 KiB
Go

// Copyright 2018 Prometheus Team
// 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 cluster
import (
"bytes"
"context"
"io"
"os"
"testing"
"github.com/go-kit/kit/log"
"github.com/hashicorp/memberlist"
"github.com/prometheus/client_golang/prometheus"
)
func TestNormalMessagesGossiped(t *testing.T) {
var sent bool
c := newChannel(
func(_ []byte) { sent = true },
func() []*memberlist.Node { return nil },
func(_ *memberlist.Node, _ []byte) error { return nil },
)
c.Broadcast([]byte{})
if sent != true {
t.Fatalf("small message not sent")
}
}
func TestOversizedMessagesGossiped(t *testing.T) {
var sent bool
ctx, cancel := context.WithCancel(context.Background())
c := newChannel(
func(_ []byte) {},
func() []*memberlist.Node { return []*memberlist.Node{&memberlist.Node{}} },
func(_ *memberlist.Node, _ []byte) error { sent = true; cancel(); return nil },
)
f, err := os.Open("/dev/zero")
if err != nil {
t.Fatalf("failed to open /dev/zero: %v", err)
}
defer f.Close()
buf := new(bytes.Buffer)
toCopy := int64(800)
if n, err := io.CopyN(buf, f, toCopy); err != nil {
t.Fatalf("failed to copy bytes: %v", err)
} else if n != toCopy {
t.Fatalf("wanted to copy %d bytes, only copied %d", toCopy, n)
}
c.Broadcast(buf.Bytes())
<-ctx.Done()
if sent != true {
t.Fatalf("oversized message not sent")
}
}
func newChannel(
send func([]byte),
peers func() []*memberlist.Node,
sendOversize func(*memberlist.Node, []byte) error,
) *Channel {
return NewChannel(
"test",
send,
peers,
sendOversize,
log.NewNopLogger(),
make(chan struct{}),
prometheus.NewRegistry(),
)
}