|
| 1 | +/** |
| 2 | + * Licensed to the Apache Software Foundation (ASF) under one |
| 3 | + * or more contributor license agreements. See the NOTICE file |
| 4 | + * distributed with this work for additional information |
| 5 | + * regarding copyright ownership. The ASF licenses this file |
| 6 | + * to you under the Apache License, Version 2.0 (the |
| 7 | + * "License"); you may not use this file except in compliance |
| 8 | + * with the License. You may obtain a copy of the License at |
| 9 | + * |
| 10 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | + * |
| 12 | + * Unless required by applicable law or agreed to in writing, |
| 13 | + * software distributed under the License is distributed on an |
| 14 | + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | + * KIND, either express or implied. See the License for the |
| 16 | + * specific language governing permissions and limitations |
| 17 | + * under the License. |
| 18 | + */ |
| 19 | +#ifndef PULSAR_AUTO_CLUSTER_FAILOVER_H_ |
| 20 | +#define PULSAR_AUTO_CLUSTER_FAILOVER_H_ |
| 21 | + |
| 22 | +#include <pulsar/ServiceInfoProvider.h> |
| 23 | + |
| 24 | +#include <chrono> |
| 25 | +#include <cstdint> |
| 26 | +#include <functional> |
| 27 | +#include <memory> |
| 28 | +#include <vector> |
| 29 | + |
| 30 | +namespace pulsar { |
| 31 | + |
| 32 | +class Client; |
| 33 | +class AutoClusterFailoverImpl; |
| 34 | + |
| 35 | +class PULSAR_PUBLIC AutoClusterFailover final : public ServiceInfoProvider { |
| 36 | + public: |
| 37 | + struct Config { |
| 38 | + const ServiceInfo primary; |
| 39 | + const std::vector<ServiceInfo> secondary; |
| 40 | + std::chrono::milliseconds checkInterval{5000}; // 5 seconds |
| 41 | + uint32_t failoverThreshold{1}; |
| 42 | + uint32_t switchBackThreshold{1}; |
| 43 | + |
| 44 | + Config(ServiceInfo primary, std::vector<ServiceInfo> secondary) |
| 45 | + : primary(std::move(primary)), secondary(std::move(secondary)) {} |
| 46 | + }; |
| 47 | + |
| 48 | + /** |
| 49 | + * Builder helps create an AutoClusterFailover configuration. |
| 50 | + * |
| 51 | + * Example: |
| 52 | + * ServiceInfo primary{...}; |
| 53 | + * std::vector<ServiceInfo> secondaries{...}; |
| 54 | + * AutoClusterFailover provider = AutoClusterFailover::Builder(primary, secondaries) |
| 55 | + * .withCheckInterval(std::chrono::seconds(5)) |
| 56 | + * .withFailoverThreshold(3) |
| 57 | + * .withSwitchBackThreshold(3) |
| 58 | + * .build(); |
| 59 | + * |
| 60 | + * Notes: |
| 61 | + * - primary: the preferred cluster to use when available. |
| 62 | + * - secondary: ordered list of fallback clusters. |
| 63 | + * - checkInterval: frequency of health probes. |
| 64 | + * - failoverThreshold: the number of consecutive failed probes required before switching away from |
| 65 | + * the current cluster. |
| 66 | + * - switchBackThreshold: the number of consecutive successful probes to the primary required before |
| 67 | + * switching back from a secondary while that secondary remains available. If the active secondary |
| 68 | + * becomes unavailable and the primary is available, the implementation may switch back to the |
| 69 | + * primary immediately, regardless of this threshold. |
| 70 | + */ |
| 71 | + class Builder { |
| 72 | + public: |
| 73 | + Builder(ServiceInfo primary, std::vector<ServiceInfo> secondary) |
| 74 | + : config_(std::move(primary), std::move(secondary)) {} |
| 75 | + |
| 76 | + // Set how frequently probes run against the active cluster(s). Default: 5 seconds. |
| 77 | + Builder& withCheckInterval(std::chrono::milliseconds interval) { |
| 78 | + config_.checkInterval = interval; |
| 79 | + return *this; |
| 80 | + } |
| 81 | + |
| 82 | + // Set the number of consecutive failed probes required before attempting failover. Default: 1. |
| 83 | + Builder& withFailoverThreshold(uint32_t threshold) { |
| 84 | + config_.failoverThreshold = threshold; |
| 85 | + return *this; |
| 86 | + } |
| 87 | + |
| 88 | + // Set the number of consecutive successful primary probes required before switching back from a |
| 89 | + // healthy secondary. If the active secondary becomes unavailable and the primary is available, |
| 90 | + // the implementation may switch back immediately regardless of this threshold. Default: 1. |
| 91 | + Builder& withSwitchBackThreshold(uint32_t threshold) { |
| 92 | + config_.switchBackThreshold = threshold; |
| 93 | + return *this; |
| 94 | + } |
| 95 | + |
| 96 | + AutoClusterFailover build() { return AutoClusterFailover(std::move(config_)); } |
| 97 | + |
| 98 | + private: |
| 99 | + Config config_; |
| 100 | + }; |
| 101 | + |
| 102 | + explicit AutoClusterFailover(Config&& config); |
| 103 | + |
| 104 | + ~AutoClusterFailover() final; |
| 105 | + |
| 106 | + ServiceInfo initialServiceInfo() final; |
| 107 | + |
| 108 | + void initialize(std::function<void(ServiceInfo)> onServiceInfoUpdate) final; |
| 109 | + |
| 110 | + private: |
| 111 | + std::shared_ptr<AutoClusterFailoverImpl> impl_; |
| 112 | +}; |
| 113 | + |
| 114 | +} // namespace pulsar |
| 115 | + |
| 116 | +#endif |
0 commit comments