Github user SolidWallOfCode commented on a diff in the pull request:
https://github.com/apache/trafficserver/pull/843#discussion_r74271671
--- Diff: plugins/experimental/carp/CarpHashAlgorithm.cc ---
@@ -0,0 +1,396 @@
+/** @file
+
+ Implements the CARP hash algorithm
+
+ @section license License
+
+ 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.
+ */
+#include <ts/ts.h>
+#include <stdio.h>
+#include <memory.h>
+#include <list>
+
+#include <iostream>
+#include <sstream>
+
+#include "Common.h"
+#include "CarpHashAlgorithm.h"
+
+using namespace std;
+
+/*****************************************************************/
+void
+HashNode::dump(string& s)
+{
+ stringstream ss;
+ string sSockaddr;
+ getStringFromSockaddr(reinterpret_cast<const struct sockaddr *>(
&forwardAddr), sSockaddr);
+
+ ss << scheme << "://" << name << ":"<<listenPort<<" ("<<sSockaddr<<")
weight:"<<weight<< (_status ? string(" UP ") : string(" DOWN "));
+ if(_statusTime) {
+ ss << "(" << time(NULL)-_statusTime<< "s ago in "<< _statusLatencyMs
<< "mS)";
+ }
+ ss << " hits:" << _hits;
+ ss << " carp_noforwarded:" << _carp_noforwarded;
+ ss << " carp_forwarded:" << _carp_forwarded;
+ ss << endl;
+ s += ss.str();
+}
+
+/*****************************************************************/
+void
+HashAlgorithm::addHost(std::string name, unsigned int port, std::string
scheme, double weight, bool self, struct sockaddr_storage fwdAddr)
+{
+ HashNode* node = new HashNode(name, port, scheme, weight, self, fwdAddr);
+ TSAssert(NULL != node);
+ addHost(node);
+}
+
+/*****************************************************************/
+void
+HashAlgorithm::addHost(HashNode* node)
+{
+ if (!node) return;
+ _hostList.push_back(node);
+}
+
+/*****************************************************************/
+HashNode*
+HashAlgorithm::findStatusByNameAndPort(const string& name, unsigned int
port,
+ size_t* index) {
+ /*
+ * Todo: This use loop to find the corresponding HashNode
+ * But the HttpClient and the Hash was related, so we
+ * could use more easier method to write the status
+ */
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ if (_hostList[ptr]->listenPort == port
+ && _hostList[ptr]->name.compare(name) == 0) { // found it
+ if (index) {
+ *index = ptr;
+ }
+ return _hostList[ptr];
+ }
+ }
+ return NULL;
+}
+
+size_t
+HashAlgorithm::findHashNodeIndex(HashNode *node) {
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ if ( _hostList[ptr] == node) {
+ return ptr;
+ }
+ }
+ return -1;
+}
+
+/*****************************************************************/
+void
+HashAlgorithm::setStatus(const string& name, unsigned int port, bool
status, time_t time, uint64_t latencyMs)
+{
+ TSDebug(DEBUG_TAG_INIT, "HashAlgorithm::setStatus name=%s status=%d",
name.c_str(), status);
+
+ HashNode* node = findStatusByNameAndPort(name,port);
+ if(node) {
+ node->setStatus(status,time,latencyMs);
+ } else {
+ TSError("Carp internal error setStatus host %s not
found",name.c_str());
+ }
+}
+
+void
+HashAlgorithm::setStatus(HashNode * node, bool status, time_t time,
uint64_t latencyMs)
+{
+ TSDebug(DEBUG_TAG_INIT, "HashAlgorithm::setStatus name=%s status=%d",
node->name.c_str(), status);
+
+// HashNode* node = findStatusByNameAndPort(name,port);
+ if(node) {
+ node->setStatus(status,time,latencyMs);
+ } else {
+ TSError("Carp internal error setStatus host %s not
found",node->name.c_str());
+ }
+}
+
+/*****************************************************************/
+HashAlgorithm::~HashAlgorithm()
+{
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ delete _hostList[ptr];
+ }
+}
+
+/*****************************************************************/
+void
+HashAlgorithm::dump(string& s)
+{
+ _config->dump(s);
+
+ stringstream ss;
+ ss << "Hash Algo stats:" << endl;
+ s += ss.str();
+
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ ss.str("");
+ ss.clear();
+ ss << ptr << "-";
+ s += ss.str();
+ _hostList[ptr]->dump(s);
+ }
+}
+
+/*****************************************************************/
+void
+CarpHashAlgorithm::algoInit()
+{
+ // calculate hash for each host
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ std::string cname;
+ char buf[64];
+ memset(buf, 0, 64);
+ snprintf(buf, 64, "%s:%d", _hostList[ptr]->name.c_str(),
_hostList[ptr]->listenPort);
+ cname = buf;
+
+ _hostList[ptr]->hash = _calculateHash(cname);
+ }
+
+ // calculate loadmultiplier
+ _calculateLoadMultiplier();
+
+ for (size_t ptr = 0; ptr < _hostList.size(); ptr++) {
+ TSDebug(DEBUG_TAG_INIT, "algoInit host=%s port=%d hash=0x%x weight=%g
loadFac=%g loadMult=%g isSelf=%d status=%d",
+ _hostList[ptr]->name.c_str(),
+ _hostList[ptr]->listenPort,
+ _hostList[ptr]->hash,
+ _hostList[ptr]->weight,
+ _hostList[ptr]->loadFactor,
+ _hostList[ptr]->loadMultiplier,
+ _hostList[ptr]->isSelf,
+ _hostList[ptr]->getStatus());
+ }
+}
+
+/*****************************************************************/
+std::vector<HashNode*>
+CarpHashAlgorithm::getRemapProxyList(const std::string& url)
+{
+ std::vector<HashNode *> hn=_selectReplicateNodes(url);
+ return hn;
+}
+
+/*****************************************************************/
+HashNode*
+CarpHashAlgorithm::getRemapProxy(const std::string& url)
+{
+ HashNode *hn=_selectNode(url);
+ if(hn) {
+ hn->hit();
+ }
+ return hn;
+}
+
+
+/*****************************************************************/
+unsigned int
+CarpHashAlgorithm::_calculateHash(const std::string& hostname)
+{
+ // check input data
+ if (hostname.empty())
+ return 0;
+
+ unsigned int hash = 0;
--- End diff --
Does the hash output have a well defined size? That is, is it specifically
a 32 bit or 64 bit (for example) hash?
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