123 lines
2.9 KiB
Go
123 lines
2.9 KiB
Go
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// Licensed to Elasticsearch B.V. under one or more contributor
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// license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright
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// ownership. Elasticsearch B.V. licenses this file to you under
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// the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package outputs
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import (
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"errors"
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"fmt"
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"math/rand"
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"strings"
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"github.com/elastic/beats/libbeat/publisher"
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"github.com/elastic/beats/libbeat/testing"
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)
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type failoverClient struct {
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clients []NetworkClient
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active int
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}
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var (
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// ErrNoConnectionConfigured indicates no configured connections for publishing.
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ErrNoConnectionConfigured = errors.New("No connection configured")
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errNoActiveConnection = errors.New("No active connection")
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)
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// NewFailoverClient combines a set of NetworkClients into one NetworkClient instances,
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// with at most one active client. If the active client fails, another client
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// will be used.
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func NewFailoverClient(clients []NetworkClient) NetworkClient {
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if len(clients) == 1 {
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return clients[0]
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}
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return &failoverClient{
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clients: clients,
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active: -1,
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}
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}
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func (f *failoverClient) Connect() error {
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var (
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next int
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active = f.active
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l = len(f.clients)
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)
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switch {
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case l == 0:
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return ErrNoConnectionConfigured
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case l == 1:
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next = 0
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case l == 2 && 0 <= active && active <= 1:
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next = 1 - active
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default:
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for {
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// Connect to random server to potentially spread the
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// load when large number of beats with same set of sinks
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// are started up at about the same time.
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next = rand.Int() % l
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if next != active {
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break
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}
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}
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}
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client := f.clients[next]
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f.active = next
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return client.Connect()
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}
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func (f *failoverClient) Close() error {
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if f.active < 0 {
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return errNoActiveConnection
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}
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return f.clients[f.active].Close()
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}
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func (f *failoverClient) Publish(batch publisher.Batch) error {
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if f.active < 0 {
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batch.Retry()
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return errNoActiveConnection
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}
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return f.clients[f.active].Publish(batch)
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}
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func (f *failoverClient) Test(d testing.Driver) {
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for i, client := range f.clients {
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c, ok := client.(testing.Testable)
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d.Run(fmt.Sprintf("Client %d", i), func(d testing.Driver) {
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if !ok {
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d.Fatal("output", errors.New("client doesn't support testing"))
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}
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c.Test(d)
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})
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}
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}
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func (f *failoverClient) String() string {
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names := make([]string, len(f.clients))
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for i, client := range f.clients {
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names[i] = client.String()
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}
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return "failover(" + strings.Join(names, ",") + ")"
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}
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