f3eade2f62
Drop the AGPL license in favor of a source-available license. See the blog post [1] for details. [1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
69 lines
2.7 KiB
C++
69 lines
2.7 KiB
C++
/*
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*
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* Modified by ScyllaDB
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* Copyright (C) 2015-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (LicenseRef-ScyllaDB-Source-Available-1.0 and Apache-2.0)
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*/
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#pragma once
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#include "gms/inet_address.hh"
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#include "gms/endpoint_state.hh"
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#include "gms/application_state.hh"
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#include "gms/versioned_value.hh"
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namespace gms {
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/**
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* This is called by the gossiper to notify
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* interested parties about changes in the the state associated with any endpoint.
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* For instance if node A figures there is a changes in state for an endpoint B
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* it notifies all interested parties of this change. It is upto to the registered
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* instance to decide what he does with this change. Not all modules maybe interested
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* in all state changes.
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*
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* All notifications that accept a permit_id are guaranteed to be called
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* under the respective endpoint lock. The permit_id must be provided
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* by the subscriber if it calls back gossiper functions that modify the same endpoint's
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* state, and therefore may acquire the same endpoint_lock - to prevent deadlock on the nested
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* call path. Calls from other code paths or for other endpoints should pass a
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* null_permit_id to indicate that no endpoint lock is held for them.
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*/
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class i_endpoint_state_change_subscriber {
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protected:
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future<> on_application_state_change(inet_address endpoint, const application_state_map& states, application_state app_state, permit_id,
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std::function<future<>(inet_address, const gms::versioned_value&, gms::permit_id)> func);
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public:
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virtual ~i_endpoint_state_change_subscriber() {}
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/**
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* Use to inform interested parties about the change in the state
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* for specified endpoint
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*
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* @param endpoint endpoint for which the state change occurred.
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* @param epState state that actually changed for the above endpoint.
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*/
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virtual future<> on_join(inet_address endpoint, endpoint_state_ptr ep_state, permit_id) = 0;
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virtual future<> on_change(inet_address endpoint, const application_state_map& states, permit_id) = 0;
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virtual future<> on_alive(inet_address endpoint, endpoint_state_ptr state, permit_id) = 0;
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virtual future<> on_dead(inet_address endpoint, endpoint_state_ptr state, permit_id) = 0;
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virtual future<> on_remove(inet_address endpoint, permit_id) = 0;
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/**
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* Called whenever a node is restarted.
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* Note that there is no guarantee when that happens that the node was
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* previously marked down. It will have only if {@code state.isAlive() == false}
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* as {@code state} is from before the restarted node is marked up.
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*/
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virtual future<> on_restart(inet_address endpoint, endpoint_state_ptr state, permit_id) = 0;
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};
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} // namespace gms
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