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conn_pool.h
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/
conn_pool.h
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#pragma once
#include <list>
#include <memory>
#include "envoy/event/deferred_deletable.h"
#include "envoy/event/timer.h"
#include "envoy/network/connection.h"
#include "envoy/network/filter.h"
#include "envoy/stats/timespan.h"
#include "envoy/tcp/conn_pool.h"
#include "envoy/upstream/upstream.h"
#include "source/common/common/linked_object.h"
#include "source/common/common/logger.h"
#include "source/common/http/conn_pool_base.h"
#include "source/common/network/filter_impl.h"
namespace Envoy {
namespace Tcp {
class ConnPoolImpl;
struct TcpAttachContext : public Envoy::ConnectionPool::AttachContext {
TcpAttachContext(Tcp::ConnectionPool::Callbacks* callbacks) : callbacks_(callbacks) {}
Tcp::ConnectionPool::Callbacks* callbacks_;
};
class TcpPendingStream : public Envoy::ConnectionPool::PendingStream {
public:
TcpPendingStream(Envoy::ConnectionPool::ConnPoolImplBase& parent, TcpAttachContext& context)
: Envoy::ConnectionPool::PendingStream(parent), context_(context) {}
Envoy::ConnectionPool::AttachContext& context() override { return context_; }
TcpAttachContext context_;
};
class ActiveTcpClient : public Envoy::ConnectionPool::ActiveClient {
public:
struct ConnReadFilter : public Network::ReadFilterBaseImpl {
ConnReadFilter(ActiveTcpClient& parent) : parent_(parent) {}
// Network::ReadFilter
Network::FilterStatus onData(Buffer::Instance& data, bool end_stream) override {
parent_.onUpstreamData(data, end_stream);
return Network::FilterStatus::StopIteration;
}
ActiveTcpClient& parent_;
};
// This acts as the bridge between the ActiveTcpClient and an individual TCP connection.
class TcpConnectionData : public Envoy::Tcp::ConnectionPool::ConnectionData {
public:
TcpConnectionData(ActiveTcpClient& parent, Network::ClientConnection& connection)
: parent_(&parent), connection_(connection) {
parent_->tcp_connection_data_ = this;
}
~TcpConnectionData() override {
// Generally it is the case that TcpConnectionData will be destroyed before the
// ActiveTcpClient. Because ordering on the deferred delete list is not guaranteed in the
// case of a disconnect, make sure parent_ is valid before doing clean-up.
if (parent_) {
parent_->clearCallbacks();
}
}
Network::ClientConnection& connection() override { return connection_; }
void setConnectionState(ConnectionPool::ConnectionStatePtr&& state) override {
parent_->connection_state_ = std::move(state);
}
void addUpstreamCallbacks(ConnectionPool::UpstreamCallbacks& callbacks) override {
parent_->callbacks_ = &callbacks;
}
void release() { parent_ = nullptr; }
protected:
ConnectionPool::ConnectionState* connectionState() override {
return parent_->connection_state_.get();
}
private:
ActiveTcpClient* parent_;
Network::ClientConnection& connection_;
};
ActiveTcpClient(Envoy::ConnectionPool::ConnPoolImplBase& parent,
const Upstream::HostConstSharedPtr& host, uint64_t concurrent_stream_limit);
~ActiveTcpClient() override;
// Override the default's of Envoy::ConnectionPool::ActiveClient for class-specific functions.
// Network::ConnectionCallbacks
void onEvent(Network::ConnectionEvent event) override;
void onAboveWriteBufferHighWatermark() override { callbacks_->onAboveWriteBufferHighWatermark(); }
void onBelowWriteBufferLowWatermark() override { callbacks_->onBelowWriteBufferLowWatermark(); }
// Undo the readDisable done in onEvent(Connected) - now that there is an associated connection,
// drain any data.
void readEnableIfNew() {
// It is expected for Envoy use of ActiveTcpClient this function only be
// called once. Other users of the TcpConnPool may recycle Tcp connections,
// and this safeguards them against read-enabling too many times.
if (!associated_before_) {
associated_before_ = true;
connection_->readDisable(false);
// Also while we're at it, make sure the connection will proxy all TCP
// data before picking up a FIN.
connection_->detectEarlyCloseWhenReadDisabled(false);
}
}
absl::optional<Http::Protocol> protocol() const override { return {}; }
void close() override { connection_->close(Network::ConnectionCloseType::NoFlush); }
uint32_t numActiveStreams() const override { return callbacks_ ? 1 : 0; }
bool closingWithIncompleteStream() const override { return false; }
uint64_t id() const override { return connection_->id(); }
void onUpstreamData(Buffer::Instance& data, bool end_stream) {
if (callbacks_) {
callbacks_->onUpstreamData(data, end_stream);
} else {
close();
}
}
virtual void clearCallbacks();
std::shared_ptr<ConnReadFilter> read_filter_handle_;
Envoy::ConnectionPool::ConnPoolImplBase& parent_;
ConnectionPool::UpstreamCallbacks* callbacks_{};
Network::ClientConnectionPtr connection_;
ConnectionPool::ConnectionStatePtr connection_state_;
TcpConnectionData* tcp_connection_data_{};
bool associated_before_{};
};
class ConnPoolImpl : public Envoy::ConnectionPool::ConnPoolImplBase,
public Tcp::ConnectionPool::Instance {
public:
ConnPoolImpl(Event::Dispatcher& dispatcher, Upstream::HostConstSharedPtr host,
Upstream::ResourcePriority priority,
const Network::ConnectionSocket::OptionsSharedPtr& options,
Network::TransportSocketOptionsSharedPtr transport_socket_options,
Upstream::ClusterConnectivityState& state)
: Envoy::ConnectionPool::ConnPoolImplBase(host, priority, dispatcher, options,
transport_socket_options, state) {}
~ConnPoolImpl() override { destructAllConnections(); }
void addDrainedCallback(DrainedCb cb) override { addDrainedCallbackImpl(cb); }
void drainConnections() override {
drainConnectionsImpl();
// Legacy behavior for the TCP connection pool marks all connecting clients
// as draining.
for (auto& connecting_client : connecting_clients_) {
if (connecting_client->remaining_streams_ > 1) {
uint64_t old_limit = connecting_client->effectiveConcurrentStreamLimit();
connecting_client->remaining_streams_ = 1;
if (connecting_client->effectiveConcurrentStreamLimit() < old_limit) {
decrConnectingAndConnectedStreamCapacity(
old_limit - connecting_client->effectiveConcurrentStreamLimit());
}
}
}
}
void closeConnections() override {
for (auto* list : {&ready_clients_, &busy_clients_, &connecting_clients_}) {
while (!list->empty()) {
list->front()->close();
}
}
}
ConnectionPool::Cancellable* newConnection(Tcp::ConnectionPool::Callbacks& callbacks) override {
TcpAttachContext context(&callbacks);
return Envoy::ConnectionPool::ConnPoolImplBase::newStream(context);
}
bool maybePreconnect(float preconnect_ratio) override {
return Envoy::ConnectionPool::ConnPoolImplBase::maybePreconnect(preconnect_ratio);
}
ConnectionPool::Cancellable*
newPendingStream(Envoy::ConnectionPool::AttachContext& context) override {
Envoy::ConnectionPool::PendingStreamPtr pending_stream =
std::make_unique<TcpPendingStream>(*this, typedContext<TcpAttachContext>(context));
return addPendingStream(std::move(pending_stream));
}
Upstream::HostDescriptionConstSharedPtr host() const override {
return Envoy::ConnectionPool::ConnPoolImplBase::host();
}
Envoy::ConnectionPool::ActiveClientPtr instantiateActiveClient() override {
return std::make_unique<ActiveTcpClient>(*this, Envoy::ConnectionPool::ConnPoolImplBase::host(),
1);
}
void onPoolReady(Envoy::ConnectionPool::ActiveClient& client,
Envoy::ConnectionPool::AttachContext& context) override {
ActiveTcpClient* tcp_client = static_cast<ActiveTcpClient*>(&client);
tcp_client->readEnableIfNew();
auto* callbacks = typedContext<TcpAttachContext>(context).callbacks_;
std::unique_ptr<Envoy::Tcp::ConnectionPool::ConnectionData> connection_data =
std::make_unique<ActiveTcpClient::TcpConnectionData>(*tcp_client, *tcp_client->connection_);
callbacks->onPoolReady(std::move(connection_data), tcp_client->real_host_description_);
}
void onPoolFailure(const Upstream::HostDescriptionConstSharedPtr& host_description,
absl::string_view failure_reason, ConnectionPool::PoolFailureReason reason,
Envoy::ConnectionPool::AttachContext& context) override {
auto* callbacks = typedContext<TcpAttachContext>(context).callbacks_;
callbacks->onPoolFailure(reason, failure_reason, host_description);
}
// These two functions exist for testing parity between old and new Tcp Connection Pools.
virtual void onConnReleased(Envoy::ConnectionPool::ActiveClient&) {}
virtual void onConnDestroyed() {}
};
} // namespace Tcp
} // namespace Envoy