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arangodb/arangod/Cluster/AgencyComm.cpp

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#include "Cluster/AgencyComm.h"
#include "Basics/JsonHelper.h"
#include "Basics/ReadLocker.h"
#include "Basics/StringUtils.h"
#include "Basics/StringBuffer.h"
#include "Basics/VelocyPackHelper.h"
#include "Basics/WriteLocker.h"
#include "Basics/json.h"
#include "Basics/logging.h"
#include "Basics/random.h"
#include "Cluster/ServerState.h"
#include "Rest/Endpoint.h"
#include "Rest/HttpRequest.h"
#include "SimpleHttpClient/GeneralClientConnection.h"
#include "SimpleHttpClient/SimpleHttpClient.h"
#include "SimpleHttpClient/SimpleHttpResult.h"
#include <velocypack/Iterator.h>
#include <velocypack/velocypack-aliases.h>
using namespace triagens::arango;
////////////////////////////////////////////////////////////////////////////////
/// @brief creates an agency endpoint
////////////////////////////////////////////////////////////////////////////////
AgencyEndpoint::AgencyEndpoint(
triagens::rest::Endpoint* endpoint,
triagens::httpclient::GeneralClientConnection* connection)
: _endpoint(endpoint), _connection(connection), _busy(false) {}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys an agency endpoint
////////////////////////////////////////////////////////////////////////////////
AgencyEndpoint::~AgencyEndpoint() {
delete _connection;
delete _endpoint;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief constructs a communication result
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult::AgencyCommResult()
: _location(),
_message(),
_body(),
_values(),
_index(0),
_statusCode(0),
_connected(false) {}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a communication result
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult::~AgencyCommResult() {
// free all JSON data
std::map<std::string, AgencyCommResultEntry>::iterator it = _values.begin();
while (it != _values.end()) {
if ((*it).second._json != nullptr) {
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, (*it).second._json);
}
++it;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief extract the connected flag from the result
////////////////////////////////////////////////////////////////////////////////
bool AgencyCommResult::connected() const { return _connected; }
////////////////////////////////////////////////////////////////////////////////
/// @brief extract the http code from the result
////////////////////////////////////////////////////////////////////////////////
int AgencyCommResult::httpCode() const { return _statusCode; }
////////////////////////////////////////////////////////////////////////////////
/// @brief extract the error code from the result
////////////////////////////////////////////////////////////////////////////////
int AgencyCommResult::errorCode() const {
try {
std::shared_ptr<VPackBuilder> bodyBuilder =
VPackParser::fromJson(_body.c_str());
VPackSlice body = bodyBuilder->slice();
if (!body.isObject()) {
return 0;
}
// get "errorCode" attribute (0 if not exist)
return triagens::basics::VelocyPackHelper::getNumericValue<int>(
body, "errorCode", 0);
} catch (VPackException const&) {
return 0;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief extract the error message from the result
/// if there is no error, an empty string will be returned
////////////////////////////////////////////////////////////////////////////////
std::string AgencyCommResult::errorMessage() const {
if (!_message.empty()) {
// return stored message first if set
return _message;
}
if (!_connected) {
return std::string("unable to connect to agency");
}
try {
std::shared_ptr<VPackBuilder> bodyBuilder =
VPackParser::fromJson(_body.c_str());
VPackSlice body = bodyBuilder->slice();
if (!body.isObject()) {
return "";
}
// get "message" attribute ("" if not exist)
return triagens::basics::VelocyPackHelper::getStringValue(
body, "message", "");
} catch (VPackException const&) {
return std::string("Out of memory");
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief extract the error details from the result
/// if there is no error, an empty string will be returned
////////////////////////////////////////////////////////////////////////////////
std::string AgencyCommResult::errorDetails() const {
std::string const errorMessage = this->errorMessage();
if (errorMessage.empty()) {
return _message;
}
return _message + " (" + errorMessage + ")";
}
////////////////////////////////////////////////////////////////////////////////
/// @brief flush the internal result buffer
////////////////////////////////////////////////////////////////////////////////
void AgencyCommResult::clear() {
// free existing values if any
std::map<std::string, AgencyCommResultEntry>::iterator it = _values.begin();
while (it != _values.end()) {
if ((*it).second._json != nullptr) {
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, (*it).second._json);
}
++it;
}
_values.clear();
_location = "";
_message = "";
_body = "";
_index = 0;
_statusCode = 0;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief recursively flatten the JSON response into a map
///
/// stripKeyPrefix is decoded, as is the _globalPrefix
////////////////////////////////////////////////////////////////////////////////
bool AgencyCommResult::parseVelocyPackNode(VPackSlice const& node,
std::string const& stripKeyPrefix,
bool withDirs) {
if (!node.isObject()) {
return true;
}
// get "key" attribute
VPackSlice const key = node.get("key");
if (!key.isString()) {
return false;
}
std::string keydecoded = std::move(AgencyComm::decodeKey(key.copyString()));
// make sure we don't strip more bytes than the key is long
size_t const offset =
AgencyComm::_globalPrefix.size() + stripKeyPrefix.size();
size_t const length = keydecoded.size();
std::string prefix;
if (offset >= length) {
prefix = "";
} else {
prefix = keydecoded.substr(offset);
}
// get "dir" attribute
bool isDir =
triagens::basics::VelocyPackHelper::getBooleanValue(node, "dir", false);
if (isDir) {
if (withDirs) {
AgencyCommResultEntry entry;
entry._index = 0;
entry._json = 0;
entry._isDir = true;
_values.emplace(prefix, entry);
}
// is a directory, so there may be a "nodes" attribute
VPackSlice const nodes = node.get("nodes");
if (!nodes.isArray()) {
// if directory is empty...
return true;
}
for (auto const& subNode : VPackArrayIterator(nodes)) {
if (!parseVelocyPackNode(subNode, stripKeyPrefix, withDirs)) {
return false;
}
}
} else {
// not a directory
// get "value" attribute
VPackSlice const value = node.get("value");
if (value.isString()) {
if (!prefix.empty()) {
AgencyCommResultEntry entry;
// get "modifiedIndex"
entry._index =
triagens::basics::VelocyPackHelper::stringUInt64(node.get("value"));
std::string tmp = value.copyString();
entry._json =
triagens::basics::JsonHelper::fromString(tmp.c_str(), tmp.size());
entry._isDir = false;
_values.emplace(prefix, entry);
}
}
}
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// parse an agency result
/// note that stripKeyPrefix is a decoded, normal key!
////////////////////////////////////////////////////////////////////////////////
bool AgencyCommResult::parse(std::string const& stripKeyPrefix, bool withDirs) {
std::shared_ptr<VPackBuilder> parsedBody;
try {
parsedBody = VPackParser::fromJson(_body.c_str());
} catch (...) {
return false;
}
VPackSlice slice = parsedBody->slice();
if(!slice.isObject()) {
return false;
}
// get "node" attribute
VPackSlice const node = slice.get("node");
bool const result = parseVelocyPackNode(node, stripKeyPrefix, withDirs);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief the static global URL prefix
////////////////////////////////////////////////////////////////////////////////
std::string const AgencyComm::AGENCY_URL_PREFIX = "v2/keys";
////////////////////////////////////////////////////////////////////////////////
/// @brief global (variable) prefix used for endpoint
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::_globalPrefix = "";
////////////////////////////////////////////////////////////////////////////////
/// @brief lock for the global endpoints
////////////////////////////////////////////////////////////////////////////////
triagens::basics::ReadWriteLock AgencyComm::_globalLock;
////////////////////////////////////////////////////////////////////////////////
/// @brief list of global endpoints
////////////////////////////////////////////////////////////////////////////////
std::list<AgencyEndpoint*> AgencyComm::_globalEndpoints;
////////////////////////////////////////////////////////////////////////////////
/// @brief global connection options
////////////////////////////////////////////////////////////////////////////////
AgencyConnectionOptions AgencyComm::_globalConnectionOptions = {
15.0, // connectTimeout
120.0, // requestTimeout
120.0, // lockTimeout
10 // numRetries
};
////////////////////////////////////////////////////////////////////////////////
/// @brief constructs an agency comm locker
////////////////////////////////////////////////////////////////////////////////
AgencyCommLocker::AgencyCommLocker(std::string const& key,
std::string const& type, double ttl)
: _key(key), _type(type), _json(nullptr), _version(0), _isLocked(false) {
AgencyComm comm;
_json =
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, type.c_str(), type.size());
if (_json == nullptr) {
return;
}
if (comm.lock(key, ttl, 0.0, _json)) {
fetchVersion(comm);
_isLocked = true;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys an agency comm locker
////////////////////////////////////////////////////////////////////////////////
AgencyCommLocker::~AgencyCommLocker() {
unlock();
if (_json != nullptr) {
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, _json);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief unlocks the lock
////////////////////////////////////////////////////////////////////////////////
void AgencyCommLocker::unlock() {
if (_isLocked) {
AgencyComm comm;
updateVersion(comm);
if (comm.unlock(_key, _json, 0.0)) {
_isLocked = false;
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief fetch a lock version from the agency
////////////////////////////////////////////////////////////////////////////////
bool AgencyCommLocker::fetchVersion(AgencyComm& comm) {
if (_type != "WRITE") {
return true;
}
AgencyCommResult result = comm.getValues(_key + "/Version", false);
if (!result.successful()) {
if (result.httpCode() != (int)triagens::rest::HttpResponse::NOT_FOUND) {
return false;
}
return true;
}
result.parse("", false);
std::map<std::string, AgencyCommResultEntry>::const_iterator it =
result._values.begin();
if (it == result._values.end()) {
return false;
}
_version = triagens::basics::JsonHelper::stringUInt64((*it).second._json);
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief update a lock version in the agency
////////////////////////////////////////////////////////////////////////////////
bool AgencyCommLocker::updateVersion(AgencyComm& comm) {
if (_type != "WRITE") {
return true;
}
if (_version == 0) {
TRI_json_t* json =
triagens::basics::JsonHelper::uint64String(TRI_UNKNOWN_MEM_ZONE, 1);
if (json == nullptr) {
return false;
}
// no Version key found, now set it
AgencyCommResult result =
comm.casValue(_key + "/Version", json, false, 0.0, 0.0);
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, json);
return result.successful();
} else {
// Version key found, now update it
TRI_json_t* oldJson = triagens::basics::JsonHelper::uint64String(
TRI_UNKNOWN_MEM_ZONE, _version);
if (oldJson == nullptr) {
return false;
}
TRI_json_t* newJson = triagens::basics::JsonHelper::uint64String(
TRI_UNKNOWN_MEM_ZONE, _version + 1);
if (newJson == nullptr) {
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, oldJson);
return false;
}
AgencyCommResult result =
comm.casValue(_key + "/Version", oldJson, newJson, 0.0, 0.0);
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, newJson);
TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, oldJson);
return result.successful();
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief constructs an agency communication object
////////////////////////////////////////////////////////////////////////////////
AgencyComm::AgencyComm(bool addNewEndpoints)
: _addNewEndpoints(addNewEndpoints) {}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys an agency communication object
////////////////////////////////////////////////////////////////////////////////
AgencyComm::~AgencyComm() {}
////////////////////////////////////////////////////////////////////////////////
/// @brief cleans up all connections
////////////////////////////////////////////////////////////////////////////////
void AgencyComm::cleanup() {
AgencyComm::disconnect();
while (true) {
{
bool busyFound = false;
WRITE_LOCKER(AgencyComm::_globalLock);
std::list<AgencyEndpoint*>::iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
if (agencyEndpoint->_busy) {
busyFound = true;
++it;
} else {
it = _globalEndpoints.erase(it);
delete agencyEndpoint;
}
}
if (!busyFound) {
break;
}
}
usleep(100000);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief tries to establish a communication channel
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::tryConnect() {
{
WRITE_LOCKER(AgencyComm::_globalLock);
if (_globalEndpoints.size() == 0) {
return false;
}
std::list<AgencyEndpoint*>::iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
TRI_ASSERT(agencyEndpoint->_endpoint != nullptr);
TRI_ASSERT(agencyEndpoint->_connection != nullptr);
if (agencyEndpoint->_endpoint->isConnected()) {
return true;
}
agencyEndpoint->_endpoint->connect(
_globalConnectionOptions._connectTimeout,
_globalConnectionOptions._requestTimeout);
if (agencyEndpoint->_endpoint->isConnected()) {
return true;
}
++it;
}
}
// unable to connect to any endpoint
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief disconnects all communication channels
////////////////////////////////////////////////////////////////////////////////
void AgencyComm::disconnect() {
WRITE_LOCKER(AgencyComm::_globalLock);
std::list<AgencyEndpoint*>::iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
TRI_ASSERT(agencyEndpoint->_connection != nullptr);
TRI_ASSERT(agencyEndpoint->_endpoint != nullptr);
agencyEndpoint->_connection->disconnect();
agencyEndpoint->_endpoint->disconnect();
++it;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief adds an endpoint to the endpoints list
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::addEndpoint(std::string const& endpointSpecification,
bool toFront) {
LOG_TRACE("adding global agency-endpoint '%s'",
endpointSpecification.c_str());
{
WRITE_LOCKER(AgencyComm::_globalLock);
// check if we already have got this endpoint
std::list<AgencyEndpoint*>::const_iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint const* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
if (agencyEndpoint->_endpoint->getSpecification() ==
endpointSpecification) {
// a duplicate. just ignore
return false;
}
++it;
}
// didn't find the endpoint in our list of endpoints, so now create a new
// one
for (size_t i = 0; i < NumConnections; ++i) {
AgencyEndpoint* agencyEndpoint =
createAgencyEndpoint(endpointSpecification);
if (agencyEndpoint == nullptr) {
return false;
}
if (toFront) {
AgencyComm::_globalEndpoints.push_front(agencyEndpoint);
} else {
AgencyComm::_globalEndpoints.push_back(agencyEndpoint);
}
}
}
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief checks if an endpoint is present
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::hasEndpoint(std::string const& endpointSpecification) {
{
READ_LOCKER(AgencyComm::_globalLock);
// check if we have got this endpoint
std::list<AgencyEndpoint*>::iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint const* agencyEndpoint = (*it);
if (agencyEndpoint->_endpoint->getSpecification() ==
endpointSpecification) {
return true;
}
++it;
}
}
// not found
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief get a stringified version of the endpoints
////////////////////////////////////////////////////////////////////////////////
std::vector<std::string> AgencyComm::getEndpoints() {
std::vector<std::string> result;
{
// iterate over the list of endpoints
READ_LOCKER(AgencyComm::_globalLock);
std::list<AgencyEndpoint*>::const_iterator it =
AgencyComm::_globalEndpoints.begin();
while (it != AgencyComm::_globalEndpoints.end()) {
AgencyEndpoint const* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
result.push_back(agencyEndpoint->_endpoint->getSpecification());
++it;
}
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief get a stringified version of the endpoints
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::getEndpointsString() {
std::string result;
{
// iterate over the list of endpoints
READ_LOCKER(AgencyComm::_globalLock);
std::list<AgencyEndpoint*>::const_iterator it =
AgencyComm::_globalEndpoints.begin();
while (it != AgencyComm::_globalEndpoints.end()) {
if (!result.empty()) {
result += ", ";
}
AgencyEndpoint const* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
result.append(agencyEndpoint->_endpoint->getSpecification());
++it;
}
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sets the global prefix for all operations
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::setPrefix(std::string const& prefix) {
// agency prefix must not be changed
_globalPrefix = prefix;
// make sure prefix starts with a forward slash
if (prefix[0] != '/') {
_globalPrefix = '/' + _globalPrefix;
}
// make sure prefix ends with a forward slash
if (_globalPrefix.size() > 0) {
if (_globalPrefix[_globalPrefix.size() - 1] != '/') {
_globalPrefix += '/';
}
}
LOG_TRACE("setting agency-prefix to '%s'", prefix.c_str());
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief gets the global prefix for all operations
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::prefix() { return _globalPrefix; }
////////////////////////////////////////////////////////////////////////////////
/// @brief generate a timestamp
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::generateStamp() {
time_t tt = time(0);
struct tm tb;
char buffer[21];
TRI_gmtime(tt, &tb);
size_t len = ::strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%SZ", &tb);
return std::string(buffer, len);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new agency endpoint
////////////////////////////////////////////////////////////////////////////////
AgencyEndpoint* AgencyComm::createAgencyEndpoint(
std::string const& endpointSpecification) {
std::unique_ptr<triagens::rest::Endpoint> endpoint(
triagens::rest::Endpoint::clientFactory(endpointSpecification));
if (endpoint == nullptr) {
// could not create endpoint...
return nullptr;
}
std::unique_ptr<triagens::httpclient::GeneralClientConnection> connection(
triagens::httpclient::GeneralClientConnection::factory(
endpoint.get(), _globalConnectionOptions._requestTimeout,
_globalConnectionOptions._connectTimeout,
_globalConnectionOptions._connectRetries, 0));
if (connection == nullptr) {
return nullptr;
}
auto ep = new AgencyEndpoint(endpoint.get(), connection.get());
endpoint.release();
connection.release();
return ep;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sends the current server state to the agency
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::sendServerState(double ttl) {
// construct JSON value { "status": "...", "time": "..." }
std::unique_ptr<TRI_json_t> json(
TRI_CreateObjectJson(TRI_UNKNOWN_MEM_ZONE, 2));
if (json == nullptr) {
return AgencyCommResult();
}
std::string const status =
ServerState::stateToString(ServerState::instance()->getState());
std::string const stamp = std::move(AgencyComm::generateStamp());
TRI_Insert3ObjectJson(
TRI_UNKNOWN_MEM_ZONE, json.get(), "status",
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, status.c_str(),
status.size()));
TRI_Insert3ObjectJson(TRI_UNKNOWN_MEM_ZONE, json.get(), "time",
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE,
stamp.c_str(), stamp.size()));
AgencyCommResult result(
setValue("Sync/ServerStates/" + ServerState::instance()->getId(),
json.get(), ttl));
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief gets the backend version
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::getVersion() {
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_GET,
_globalConnectionOptions._requestTimeout, result, "version",
"", false);
if (result.successful()) {
return result._body;
}
return "";
}
////////////////////////////////////////////////////////////////////////////////
/// @brief update a version number in the agency
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::increaseVersion(std::string const& key) {
// fetch existing version number
AgencyCommResult result = getValues(key, false);
if (!result.successful()) {
if (result.httpCode() != (int)triagens::rest::HttpResponse::NOT_FOUND) {
return false;
}
// no version key found, now set it
std::unique_ptr<TRI_json_t> json(
triagens::basics::JsonHelper::uint64String(TRI_UNKNOWN_MEM_ZONE, 1));
if (json == nullptr) {
return false;
}
result.clear();
result = casValue(key, json.get(), false, 0.0, 0.0);
return result.successful();
}
// found a version
result.parse("", false);
auto it = result._values.begin();
if (it == result._values.end()) {
return false;
}
uint64_t version =
triagens::basics::JsonHelper::stringUInt64((*it).second._json);
// version key found, now update it
std::unique_ptr<TRI_json_t> oldJson(
triagens::basics::JsonHelper::uint64String(TRI_UNKNOWN_MEM_ZONE,
version));
if (oldJson == nullptr) {
return false;
}
std::unique_ptr<TRI_json_t> newJson(
triagens::basics::JsonHelper::uint64String(TRI_UNKNOWN_MEM_ZONE,
version + 1));
if (newJson == nullptr) {
return false;
}
result.clear();
result = casValue(key, oldJson.get(), newJson.get(), 0.0, 0.0);
return result.successful();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief update a version number in the agency, retry until it works
////////////////////////////////////////////////////////////////////////////////
void AgencyComm::increaseVersionRepeated(std::string const& key) {
bool ok = false;
while (!ok) {
ok = increaseVersion(key);
if (ok) {
return;
}
uint32_t val = 300 + TRI_UInt32Random() % 400;
LOG_INFO("Could not increase %s in agency, retrying in %dms!", key.c_str(),
val);
usleep(val * 1000);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a directory in the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::createDirectory(std::string const& key) {
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
_globalConnectionOptions._requestTimeout, result,
buildUrl(key) + "?dir=true", "", false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sets a value in the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::setValue(std::string const& key,
TRI_json_t const* json, double ttl) {
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
_globalConnectionOptions._requestTimeout, result,
buildUrl(key) + ttlParam(ttl, true),
"value=" + triagens::basics::StringUtils::urlEncode(
triagens::basics::JsonHelper::toString(json)),
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sets a value in the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::setValue(std::string const& key,
arangodb::velocypack::Slice const json,
double ttl) {
AgencyCommResult result;
sendWithFailover(
triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
_globalConnectionOptions._requestTimeout, result,
buildUrl(key) + ttlParam(ttl, true),
"value=" + triagens::basics::StringUtils::urlEncode(json.toJson()),
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief checks if a key exists
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::exists(std::string const& key) {
std::string url(buildUrl(key));
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_GET,
_globalConnectionOptions._requestTimeout, result, url, "",
false);
return result.successful();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief gets one or multiple values from the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::getValues(std::string const& key, bool recursive) {
std::string url(buildUrl(key));
if (recursive) {
url += "?recursive=true";
}
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_GET,
_globalConnectionOptions._requestTimeout, result, url, "",
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief removes one or multiple values from the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::removeValues(std::string const& key,
bool recursive) {
std::string url;
if (key.empty() && recursive) {
// delete everything, recursive
url = buildUrl();
} else {
url = buildUrl(key);
}
if (recursive) {
url += "?recursive=true";
}
AgencyCommResult result;
sendWithFailover(triagens::rest::HttpRequest::HTTP_REQUEST_DELETE,
_globalConnectionOptions._requestTimeout, result, url, "",
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compares and swaps a single value in the backend
/// the CAS condition is whether or not a previous value existed for the key
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::casValue(std::string const& key,
TRI_json_t const* json, bool prevExist,
double ttl, double timeout) {
AgencyCommResult result;
sendWithFailover(
triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
timeout == 0.0 ? _globalConnectionOptions._requestTimeout : timeout,
result, buildUrl(key) + "?prevExist=" + (prevExist ? "true" : "false") +
ttlParam(ttl, false),
"value=" + triagens::basics::StringUtils::urlEncode(
triagens::basics::JsonHelper::toString(json)),
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compares and swaps a single value in the backend
/// the CAS condition is whether or not a previous value existed for the key
/// velocypack variant
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::casValue(std::string const& key,
arangodb::velocypack::Slice const json,
bool prevExist, double ttl,
double timeout) {
AgencyCommResult result;
sendWithFailover(
triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
timeout == 0.0 ? _globalConnectionOptions._requestTimeout : timeout,
result, buildUrl(key) + "?prevExist=" + (prevExist ? "true" : "false") +
ttlParam(ttl, false),
"value=" + triagens::basics::StringUtils::urlEncode(json.toJson()),
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compares and swaps a single value in the backend
/// the CAS condition is whether or not the previous value for the key was
/// identical to `oldValue`
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::casValue(std::string const& key,
TRI_json_t const* oldJson,
TRI_json_t const* newJson, double ttl,
double timeout) {
AgencyCommResult result;
sendWithFailover(
triagens::rest::HttpRequest::HTTP_REQUEST_PUT,
timeout == 0.0 ? _globalConnectionOptions._requestTimeout : timeout,
result, buildUrl(key) + "?prevValue=" +
triagens::basics::StringUtils::urlEncode(
triagens::basics::JsonHelper::toString(oldJson)) +
ttlParam(ttl, false),
"value=" + triagens::basics::StringUtils::urlEncode(
triagens::basics::JsonHelper::toString(newJson)),
false);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief blocks on a change of a single value in the backend
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::watchValue(std::string const& key,
uint64_t waitIndex, double timeout,
bool recursive) {
std::string url(buildUrl(key) + "?wait=true");
if (waitIndex > 0) {
url += "&waitIndex=" + triagens::basics::StringUtils::itoa(waitIndex);
}
if (recursive) {
url += "&recursive=true";
}
AgencyCommResult result;
sendWithFailover(
triagens::rest::HttpRequest::HTTP_REQUEST_GET,
timeout == 0.0 ? _globalConnectionOptions._requestTimeout : timeout,
result, url, "", true);
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief acquire a read lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::lockRead(std::string const& key, double ttl, double timeout) {
std::unique_ptr<TRI_json_t> json(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "READ", strlen("READ")));
if (json == nullptr) {
return false;
}
return lock(key, ttl, timeout, json.get());
}
////////////////////////////////////////////////////////////////////////////////
/// @brief acquire a write lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::lockWrite(std::string const& key, double ttl, double timeout) {
std::unique_ptr<TRI_json_t> json(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "WRITE", strlen("WRITE")));
if (json == nullptr) {
return false;
}
return lock(key, ttl, timeout, json.get());
}
////////////////////////////////////////////////////////////////////////////////
/// @brief release a read lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::unlockRead(std::string const& key, double timeout) {
std::unique_ptr<TRI_json_t> json(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "READ", strlen("READ")));
if (json == nullptr) {
return false;
}
return unlock(key, json.get(), timeout);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief release a write lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::unlockWrite(std::string const& key, double timeout) {
std::unique_ptr<TRI_json_t> json(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "WRITE", strlen("WRITE")));
if (json == nullptr) {
return false;
}
return unlock(key, json.get(), timeout);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief get unique id
////////////////////////////////////////////////////////////////////////////////
AgencyCommResult AgencyComm::uniqid(std::string const& key, uint64_t count,
double timeout) {
static int const maxTries = 10;
int tries = 0;
AgencyCommResult result;
while (tries++ < maxTries) {
result.clear();
result = getValues(key, false);
if (result.httpCode() == (int)triagens::rest::HttpResponse::NOT_FOUND) {
std::unique_ptr<TRI_json_t> json(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "0", strlen("0")));
if (json != nullptr) {
// create the key on the fly
setValue(key, json.get(), 0.0);
tries--;
continue;
}
}
if (!result.successful()) {
return result;
}
result.parse("", false);
std::unique_ptr<TRI_json_t> oldJson;
std::map<std::string, AgencyCommResultEntry>::iterator it =
result._values.begin();
if (it != result._values.end()) {
// steal the json
oldJson.reset((*it).second._json);
(*it).second._json = nullptr;
} else {
oldJson.reset(
TRI_CreateStringCopyJson(TRI_UNKNOWN_MEM_ZONE, "0", strlen("0")));
}
if (oldJson == nullptr) {
return AgencyCommResult();
}
uint64_t const oldValue =
triagens::basics::JsonHelper::stringUInt64(oldJson.get()) + count;
uint64_t const newValue = oldValue + count;
std::unique_ptr<TRI_json_t> newJson(
triagens::basics::JsonHelper::uint64String(TRI_UNKNOWN_MEM_ZONE,
newValue));
if (newJson == nullptr) {
return AgencyCommResult();
}
result.clear();
result = casValue(key, oldJson.get(), newJson.get(), 0.0, timeout);
if (result.successful()) {
result._index = oldValue + 1;
break;
}
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a ttl query parameter
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::ttlParam(double ttl, bool isFirst) {
if ((int)ttl <= 0) {
return "";
}
return (isFirst ? "?ttl=" : "&ttl=") +
triagens::basics::StringUtils::itoa((int)ttl);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief acquires a lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::lock(std::string const& key, double ttl, double timeout,
TRI_json_t const* json) {
if (ttl == 0.0) {
ttl = _globalConnectionOptions._lockTimeout;
}
if (timeout == 0.0) {
timeout = _globalConnectionOptions._lockTimeout;
}
unsigned long sleepTime = InitialSleepTime;
double const end = TRI_microtime() + timeout;
std::unique_ptr<TRI_json_t> oldJson(TRI_CreateStringCopyJson(
TRI_UNKNOWN_MEM_ZONE, "UNLOCKED", strlen("UNLOCKED")));
if (oldJson == nullptr) {
return false;
}
while (true) {
AgencyCommResult result =
casValue(key + "/Lock", oldJson.get(), json, ttl, timeout);
if (!result.successful() &&
result.httpCode() == (int)triagens::rest::HttpResponse::NOT_FOUND) {
// key does not yet exist. create it now
result = casValue(key + "/Lock", json, false, ttl, timeout);
}
if (result.successful()) {
return true;
}
usleep(sleepTime);
if (sleepTime < MaxSleepTime) {
sleepTime += InitialSleepTime;
}
if (TRI_microtime() >= end) {
return false;
}
}
TRI_ASSERT(false);
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief releases a lock
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::unlock(std::string const& key, TRI_json_t const* json,
double timeout) {
if (timeout == 0.0) {
timeout = _globalConnectionOptions._lockTimeout;
}
unsigned long sleepTime = InitialSleepTime;
double const end = TRI_microtime() + timeout;
std::unique_ptr<TRI_json_t> newJson(TRI_CreateStringCopyJson(
TRI_UNKNOWN_MEM_ZONE, "UNLOCKED", strlen("UNLOCKED")));
if (newJson == nullptr) {
return false;
}
while (true) {
AgencyCommResult result =
casValue(key + "/Lock", json, newJson.get(), 0.0, timeout);
if (result.successful()) {
return true;
}
usleep(sleepTime);
if (sleepTime < MaxSleepTime) {
sleepTime += InitialSleepTime;
}
if (TRI_microtime() >= end) {
return false;
}
}
TRI_ASSERT(false);
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief pop an endpoint from the queue
////////////////////////////////////////////////////////////////////////////////
AgencyEndpoint* AgencyComm::popEndpoint(std::string const& endpoint) {
unsigned long sleepTime = InitialSleepTime;
while (1) {
{
WRITE_LOCKER(AgencyComm::_globalLock);
size_t const numEndpoints TRI_UNUSED = _globalEndpoints.size();
std::list<AgencyEndpoint*>::iterator it = _globalEndpoints.begin();
while (it != _globalEndpoints.end()) {
AgencyEndpoint* agencyEndpoint = (*it);
TRI_ASSERT(agencyEndpoint != nullptr);
if (!endpoint.empty() &&
agencyEndpoint->_endpoint->getSpecification() != endpoint) {
// we're looking for a different endpoint
++it;
continue;
}
if (!agencyEndpoint->_busy) {
agencyEndpoint->_busy = true;
if (AgencyComm::_globalEndpoints.size() > 1) {
// remove from list
AgencyComm::_globalEndpoints.remove(agencyEndpoint);
// and re-insert at end
AgencyComm::_globalEndpoints.push_back(agencyEndpoint);
}
TRI_ASSERT(_globalEndpoints.size() == numEndpoints);
return agencyEndpoint;
}
++it;
}
}
// if we got here, we ran out of non-busy connections...
usleep(sleepTime);
if (sleepTime < MaxSleepTime) {
sleepTime += InitialSleepTime;
}
}
// just to shut up compilers
TRI_ASSERT(false);
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief reinsert an endpoint into the queue
////////////////////////////////////////////////////////////////////////////////
void AgencyComm::requeueEndpoint(AgencyEndpoint* agencyEndpoint,
bool wasWorking) {
WRITE_LOCKER(AgencyComm::_globalLock);
size_t const numEndpoints TRI_UNUSED = _globalEndpoints.size();
TRI_ASSERT(agencyEndpoint != nullptr);
TRI_ASSERT(agencyEndpoint->_busy);
// set to non-busy
agencyEndpoint->_busy = false;
if (AgencyComm::_globalEndpoints.size() > 1) {
if (wasWorking) {
// remove from list
AgencyComm::_globalEndpoints.remove(agencyEndpoint);
// and re-insert at front
AgencyComm::_globalEndpoints.push_front(agencyEndpoint);
}
}
TRI_ASSERT(_globalEndpoints.size() == numEndpoints);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief construct a URL
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::buildUrl(std::string const& relativePart) const {
return AgencyComm::AGENCY_URL_PREFIX +
std::move(encodeKey(_globalPrefix + relativePart));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief construct a URL, without a key
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::buildUrl() const {
return AgencyComm::AGENCY_URL_PREFIX +
std::move(
encodeKey(_globalPrefix.substr(0, _globalPrefix.size() - 1)));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sends an HTTP request to the agency, handling failover
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::sendWithFailover(
triagens::rest::HttpRequest::HttpRequestType method, double const timeout,
AgencyCommResult& result, std::string const& url, std::string const& body,
bool isWatch) {
size_t numEndpoints;
{
READ_LOCKER(AgencyComm::_globalLock);
numEndpoints = AgencyComm::_globalEndpoints.size();
if (numEndpoints == 0) {
return false;
}
}
TRI_ASSERT(numEndpoints > 0);
size_t tries = 0;
std::string realUrl = url;
std::string forceEndpoint;
while (tries++ < numEndpoints) {
AgencyEndpoint* agencyEndpoint = popEndpoint(forceEndpoint);
TRI_ASSERT(agencyEndpoint != nullptr);
try {
send(agencyEndpoint->_connection, method, timeout, result, realUrl, body);
} catch (...) {
result._connected = false;
result._statusCode = 0;
result._message = "could not send request to agency";
agencyEndpoint->_connection->disconnect();
requeueEndpoint(agencyEndpoint, true);
return false;
}
if (result._statusCode ==
(int)triagens::rest::HttpResponse::TEMPORARY_REDIRECT) {
// sometimes the agency will return a 307 (temporary redirect)
// in this case we have to pick it up and use the new location returned
// put the current connection to the end of the list
requeueEndpoint(agencyEndpoint, false);
// a 307 does not count as a success
TRI_ASSERT(!result.successful());
std::string endpoint;
// transform location into an endpoint
if (result.location().substr(0, 7) == "http://") {
endpoint = "tcp://" + result.location().substr(7);
} else if (result.location().substr(0, 8) == "https://") {
endpoint = "ssl://" + result.location().substr(8);
} else {
// invalid endpoint, return an error
return false;
}
size_t const delim = endpoint.find('/', 6);
if (delim == std::string::npos) {
// invalid location header
return false;
}
realUrl = endpoint.substr(delim);
endpoint = endpoint.substr(0, delim);
if (!AgencyComm::hasEndpoint(endpoint)) {
// redirection to an unknown endpoint
if (_addNewEndpoints) {
AgencyComm::addEndpoint(endpoint, true);
LOG_INFO("adding agency-endpoint '%s'", endpoint.c_str());
// re-check the new endpoint
if (AgencyComm::hasEndpoint(endpoint)) {
++numEndpoints;
continue;
}
}
LOG_ERROR(
"found redirection to unknown endpoint '%s'. Will not follow!",
endpoint.c_str());
// this is an error
return false;
}
forceEndpoint = endpoint;
// if we get here, we'll just use the next endpoint from the list
continue;
}
forceEndpoint = "";
// we can stop iterating over endpoints if the operation succeeded,
// if a watch timed out or
// if the reason for failure was a client-side error
bool const canAbort =
result.successful() || (isWatch && result._statusCode == 0) ||
(result._statusCode >= 400 && result._statusCode <= 499);
requeueEndpoint(agencyEndpoint, canAbort);
if (canAbort) {
// we're done
return true;
}
// otherwise, try next
}
// if we get here, we could not send data to any endpoint successfully
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sends data to the URL
////////////////////////////////////////////////////////////////////////////////
bool AgencyComm::send(triagens::httpclient::GeneralClientConnection* connection,
triagens::rest::HttpRequest::HttpRequestType method,
double timeout, AgencyCommResult& result,
std::string const& url, std::string const& body) {
TRI_ASSERT(connection != nullptr);
if (method == triagens::rest::HttpRequest::HTTP_REQUEST_GET ||
method == triagens::rest::HttpRequest::HTTP_REQUEST_HEAD ||
method == triagens::rest::HttpRequest::HTTP_REQUEST_DELETE) {
TRI_ASSERT(body.empty());
}
TRI_ASSERT(!url.empty());
result._connected = false;
result._statusCode = 0;
LOG_TRACE("sending %s request to agency at endpoint '%s', url '%s': %s",
triagens::rest::HttpRequest::translateMethod(method).c_str(),
connection->getEndpoint()->getSpecification().c_str(), url.c_str(),
body.c_str());
triagens::httpclient::SimpleHttpClient client(connection, timeout, false);
client.keepConnectionOnDestruction(true);
// set up headers
std::map<std::string, std::string> headers;
if (method == triagens::rest::HttpRequest::HTTP_REQUEST_PUT ||
method == triagens::rest::HttpRequest::HTTP_REQUEST_POST) {
// the agency needs this content-type for the body
headers["content-type"] = "application/x-www-form-urlencoded";
}
// send the actual request
std::unique_ptr<triagens::httpclient::SimpleHttpResult> response(
client.request(method, url, body.c_str(), body.size(), headers));
if (response == nullptr) {
connection->disconnect();
result._message = "could not send request to agency";
LOG_TRACE("sending request to agency failed");
return false;
}
if (!response->isComplete()) {
connection->disconnect();
result._message = "sending request to agency failed";
LOG_TRACE("sending request to agency failed");
return false;
}
result._connected = true;
if (response->getHttpReturnCode() ==
(int)triagens::rest::HttpResponse::TEMPORARY_REDIRECT) {
// temporary redirect. now save location header
bool found = false;
result._location = response->getHeaderField("location", found);
LOG_TRACE("redirecting to location: '%s'", result._location.c_str());
if (!found) {
// a 307 without a location header does not make any sense
connection->disconnect();
result._message = "invalid agency response (header missing)";
return false;
}
}
result._message = response->getHttpReturnMessage();
basics::StringBuffer& sb = response->getBody();
result._body = std::string(sb.c_str(), sb.length());
result._index = 0;
result._statusCode = response->getHttpReturnCode();
bool found = false;
std::string lastIndex = response->getHeaderField("x-etcd-index", found);
if (found) {
result._index = triagens::basics::StringUtils::uint64(lastIndex);
}
LOG_TRACE(
"request to agency returned status code %d, message: '%s', body: '%s'",
result._statusCode, result._message.c_str(), result._body.c_str());
if (result.successful()) {
return true;
}
connection->disconnect();
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief encode a key for etcd
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::encodeKey(std::string const& s) {
std::string::const_iterator i;
std::string res;
for (i = s.begin(); i != s.end(); ++i) {
if (*i == '_') {
res.push_back('@');
res.push_back('U');
} else if (*i == '@') {
res.push_back('@');
res.push_back('@');
} else {
res.push_back(*i);
}
}
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief decode a key for etcd
////////////////////////////////////////////////////////////////////////////////
std::string AgencyComm::decodeKey(std::string const& s) {
std::string::const_iterator i;
std::string res;
for (i = s.begin(); i != s.end(); ++i) {
if (*i == '@') {
++i;
if (*i == 'U') {
res.push_back('_');
} else {
res.push_back('@');
}
} else {
res.push_back(*i);
}
}
return res;
}
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