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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
#pragma once
#include "strategy.h"
#include "healthstatus.h"
class PLNextHopSelectionStrategy;
constexpr const unsigned int PL_NH_MAX_GROUP_RINGS = 5;
enum PLNHHashKeyType {
PL_NH_URL_HASH_KEY = 0,
PL_NH_HOSTNAME_HASH_KEY,
PL_NH_PATH_HASH_KEY, // default, consistent hash uses the request url path
PL_NH_PATH_QUERY_HASH_KEY,
PL_NH_PATH_FRAGMENT_HASH_KEY,
PL_NH_CACHE_HASH_KEY
};
// The transaction state needed by PLNextHopConsistentHash about the last parent found,
// which is needed to find the next parent.
// Does not include the data already in ResponseAction.
//
// TODO initialize? zero? -1?
struct PLNextHopConsistentHashTxn {
PLNHParentResultType result = PL_NH_PARENT_UNDEFINED;
bool chash_init[PL_NH_MAX_GROUP_RINGS] = {false};
TSHostStatus first_choice_status = TSHostStatus::TS_HOST_STATUS_INIT;
int line_number = -1;
uint32_t last_parent;
uint32_t start_parent;
uint32_t last_group;
bool wrap_around;
bool mapWrapped[2];
int last_lookup;
ATSConsistentHashIter chashIter[PL_NH_MAX_GROUP_RINGS];
const char *hostname = "";
size_t hostname_len = 0;
in_port_t port = 0;
bool retry = false;
bool no_cache = false;
};
class PLNextHopConsistentHash : public PLNextHopSelectionStrategy
{
std::vector<std::shared_ptr<ATSConsistentHash>> rings;
uint64_t getHashKey(uint64_t sm_id, TSMBuffer reqp, TSMLoc url, TSMLoc parent_selection_url, ATSHash64 *h);
std::shared_ptr<PLHostRecord> chashLookup(const std::shared_ptr<ATSConsistentHash> &ring, uint32_t cur_ring,
PLNextHopConsistentHashTxn *state, bool *wrapped, uint64_t sm_id, TSMBuffer reqp,
TSMLoc url, TSMLoc parent_selection_url);
public:
const uint32_t LineNumberPlaceholder = 99999;
PLNHHashKeyType hash_key = PL_NH_PATH_HASH_KEY;
PLNextHopConsistentHash() = delete;
PLNextHopConsistentHash(const std::string_view name, const YAML::Node &n);
~PLNextHopConsistentHash();
void next(TSHttpTxn txnp, void *strategyTxn, const char **out_hostname, size_t *out_hostname_len, in_port_t *out_port,
bool *out_retry, bool *out_no_cache, time_t now = 0) override;
void mark(TSHttpTxn txnp, void *strategyTxn, const char *hostname, const size_t hostname_len, const in_port_t port,
const PLNHCmd status, const time_t now) override;
void *newTxn() override;
void deleteTxn(void *txn) override;
};
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