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#pragma once
///@file
#include "remote-store.hh"
#include "worker-protocol.hh"
#include "pool.hh"
namespace nix {
/**
* Bidirectional connection (send and receive) used by the Remote Store
* implementation.
*
* Contains `Source` and `Sink` for actual communication, along with
* other information learned when negotiating the connection.
*/
struct RemoteStore::Connection
{
/**
* Send with this.
*/
FdSink to;
/**
* Receive with this.
*/
FdSource from;
/**
* Worker protocol version used for the connection.
*
* Despite its name, I think it is actually the maximum version both
* sides support. (If the maximum doesn't exist, we would fail to
* establish a connection and produce a value of this type.)
*/
WorkerProto::Version daemonVersion;
/**
* Whether the remote side trusts us or not.
*
* 3 values: "yes", "no", or `std::nullopt` for "unknown".
*
* Note that the "remote side" might not be just the end daemon, but
* also an intermediary forwarder that can make its own trusting
* decisions. This would be the intersection of all their trust
* decisions, since it takes only one link in the chain to start
* denying operations.
*/
std::optional<TrustedFlag> remoteTrustsUs;
/**
* The version of the Nix daemon that is processing our requests.
*
* Do note, it may or may not communicating with another daemon,
* rather than being an "end" `LocalStore` or similar.
*/
std::optional<std::string> daemonNixVersion;
/**
* Time this connection was established.
*/
std::chrono::time_point<std::chrono::steady_clock> startTime;
/**
* Coercion to `WorkerProto::ReadConn`. This makes it easy to use the
* factored out worker protocol searlizers with a
* `RemoteStore::Connection`.
*
* The worker protocol connection types are unidirectional, unlike
* this type.
*/
operator WorkerProto::ReadConn ()
{
return WorkerProto::ReadConn {
.from = from,
.version = daemonVersion,
};
}
/**
* Coercion to `WorkerProto::WriteConn`. This makes it easy to use the
* factored out worker protocol searlizers with a
* `RemoteStore::Connection`.
*
* The worker protocol connection types are unidirectional, unlike
* this type.
*/
operator WorkerProto::WriteConn ()
{
return WorkerProto::WriteConn {
.to = to,
.version = daemonVersion,
};
}
virtual ~Connection();
virtual void closeWrite() = 0;
std::exception_ptr processStderr(Sink * sink = 0, Source * source = 0, bool flush = true);
};
/**
* A wrapper around Pool<RemoteStore::Connection>::Handle that marks
* the connection as bad (causing it to be closed) if a non-daemon
* exception is thrown before the handle is closed. Such an exception
* causes a deviation from the expected protocol and therefore a
* desynchronization between the client and daemon.
*/
struct RemoteStore::ConnectionHandle
{
Pool<RemoteStore::Connection>::Handle handle;
bool daemonException = false;
ConnectionHandle(Pool<RemoteStore::Connection>::Handle && handle)
: handle(std::move(handle))
{ }
ConnectionHandle(ConnectionHandle && h)
: handle(std::move(h.handle))
{ }
~ConnectionHandle();
RemoteStore::Connection & operator * () { return *handle; }
RemoteStore::Connection * operator -> () { return &*handle; }
void processStderr(Sink * sink = 0, Source * source = 0, bool flush = true);
void withFramedSink(std::function<void(Sink & sink)> fun);
};
}
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