clboss/Boss/Mod/ChannelFinderByPopularity.cpp

497 lines
12 KiB
C++

#include"Boss/Mod/ChannelFinderByPopularity.hpp"
#include"Boss/Mod/Rpc.hpp"
#include"Boss/Mod/Waiter.hpp"
#include"Boss/Msg/Block.hpp"
#include"Boss/Msg/Init.hpp"
#include"Boss/Msg/ManifestNotification.hpp"
#include"Boss/Msg/Manifestation.hpp"
#include"Boss/Msg/Notification.hpp"
#include"Boss/Msg/ProposeChannelCandidates.hpp"
#include"Boss/Msg/SolicitChannelCandidates.hpp"
#include"Boss/Msg/TaskCompletion.hpp"
#include"Boss/concurrent.hpp"
#include"Boss/log.hpp"
#include"Boss/random_engine.hpp"
#include"Ev/Io.hpp"
#include"Ev/map.hpp"
#include"Ev/yield.hpp"
#include"Jsmn/Object.hpp"
#include"Json/Out.hpp"
#include"Ln/NodeId.hpp"
#include"S/Bus.hpp"
#include"Util/make_unique.hpp"
#include<algorithm>
#include<iterator>
#include<queue>
#include<random>
#include<set>
#include<sstream>
#include<vector>
namespace {
/** max_proposals
*
* @brief ChannelFinderByPopularity will only
* propose up to this number of nodes.
*/
auto const max_proposals = size_t(4);
/** min_channels_to_disable
*
* @brief once we have achieved this number of
* channels, ChannelFinderByPopularity will
* stop making proposals.
*/
auto const min_channels_to_disable = size_t(4);
/** min_nodes_to_process
*
* @brief if the number of nodes known by this node
* is less than this, go to sleep and try again
* later.
*/
auto const min_nodes_to_process = size_t(200);
/** seconds_after_connect
*
* @brief if we previously stopped looking for popular
* nodes, and a new connection appears, how many seconds
* should we wait for them to update us about the network?
*/
auto const seconds_after_connect = double(150);
}
namespace Boss { namespace Mod {
class ChannelFinderByPopularity::Impl {
private:
S::Bus& bus;
Boss::Mod::Waiter& waiter;
void* this_ptr;
Boss::Mod::Rpc* rpc;
Ln::NodeId self;
/* Set if we are already running. */
bool running;
/* Set if we are waiting for a while. */
bool try_later;
void start() {
running = false;
try_later = false;
bus.subscribe<Msg::Init>([this](Msg::Init const& init) {
rpc = &init.rpc;
self = init.self_id;
return Ev::lift();
});
bus.subscribe< Msg::SolicitChannelCandidates
>([this](Msg::SolicitChannelCandidates const& _) {
if (running || !rpc || !self)
return Ev::lift();
running = true;
return Boss::concurrent(Ev::lift().then([this]() {
return solicit();
}));
});
bus.subscribe< Msg::Block
>([this](Msg::Block const& _) {
if (try_later) {
try_later = false;
return Boss::concurrent(Ev::lift().then([this]() {
return solicit();
}));
}
return Ev::lift();
});
/* Also do try_later when we successfully connect. */
bus.subscribe< Msg::Manifestation
>([this](Msg::Manifestation const& _) {
return bus.raise(Msg::ManifestNotification{
"connect"
});
});
bus.subscribe< Msg::Notification
>([this](Msg::Notification const& n) {
if (n.notification != "connect")
return Ev::lift();
if (!try_later)
return Ev::lift();
try_later = false;
return Boss::concurrent(on_new_connect());
});
}
/* List of all nodes. */
std::queue<Ln::NodeId> all_nodes;
struct Popular {
Ln::NodeId node;
std::set<Ln::NodeId> peers;
};
/* A-Chao algorithm. */
double wsum;
std::vector<Popular> selected;
/* Called after a new connection while we were deferring
* a solicitation. */
Ev::Io<void> on_new_connect() {
return Boss::log( bus, Info
, "ChannelFinderByPopularity: "
"New connection, will wait %.0f seconds, "
"then re-find nodes."
, seconds_after_connect
).then([this]() {
return waiter.wait(seconds_after_connect);
}).then([this]() {
return solicit();
});
}
Ev::Io<void> solicit() {
/* First check if we have at least
* min_channels_to_disable channels.
* If so, finding by popularity self-disables.
*/
return rpc->command( "listchannels"
, Json::Out()
.start_object()
.field("source"
, std::string(self)
)
.end_object()
).then([this](Jsmn::Object res) {
if (!res.is_object() || !res.has("channels"))
return self_disable();
auto channels = res["channels"];
if (!channels.is_array())
return self_disable();
if (channels.size() >= min_channels_to_disable)
return self_disable();
return Boss::log( bus, Debug
, "ChannelFinderByPopularity: "
"Will find nodes."
).then([this]() {
return continue_solicit();
});
});
}
Ev::Io<void> self_disable() {
return Boss::log( bus, Debug
, "ChannelFinderByPopularity: "
"Voluntarily not operating, "
"we seem to have many channels."
).then([this]() {
/* Do not signal failed, since we successfully
* decided not to do anything. */
return signal_task_completion(false);
});
}
Ev::Io<void> continue_solicit() {
/* Now do listnodes for everything. */
return rpc->command( "listnodes"
, Json::Out::empty_object()
).then([this](Jsmn::Object res){
if (!res.is_object() || !res.has("nodes"))
return fail_solicit("Unexpected result from listnodes.");
auto nodes = res["nodes"];
if (!nodes.is_array())
return fail_solicit("Unexpected result from listnodes.");
if (nodes.size() < min_nodes_to_process)
return defer_solicit(nodes.size());
all_nodes = std::queue<Ln::NodeId>();
for (auto i = size_t(0); i < nodes.size(); ++i) {
auto node = nodes[i];
if (!node.is_object() || !node.has("nodeid"))
continue;
auto id = node["nodeid"];
if (!id.is_string())
continue;
all_nodes.emplace(std::string(id));
}
/* Initialize the A-Chao algorithm. */
wsum = 0;
selected.clear();
/* Print details. */
return Boss::log( bus, Debug
, "ChannelFinderByPopularity: "
"%zu nodes to be evaluated."
, all_nodes.size()
).then([this]() {
return select_by_popularity();
});
});
}
Ev::Io<void> defer_solicit(size_t n) {
try_later = true;
return Boss::log( bus, Info
, "ChannelFinderByPopularity: "
"Not enough nodes in routemap "
"(only %zu, need %zu), "
"will try again later."
, n, min_nodes_to_process
);
}
Ev::Io<void> fail_solicit(std::string const& reason) {
return Boss::log( bus, Error
, "ChannelFinderByPopularity: "
"Failed: %s"
, reason.c_str()
).then([this]() {
/* Failed! */
return signal_task_completion(true);
});
}
/* A-Chao Reservoir sampling algorithm. */
Ev::Io<void> select_by_popularity() {
return Ev::yield().then([this]() {
/* This is a loop. */
if (all_nodes.empty())
return complete_select_by_popularity();
/* Get channels of the current node. */
auto const& curr = all_nodes.front();
return rpc->command( "listchannels"
, Json::Out()
.start_object()
.field( "source"
, std::string(curr)
)
.end_object()
).then([this](Jsmn::Object res) {
auto entry = Popular();
/* Now move the current node off the queue. */
entry.node = std::move(all_nodes.front());
all_nodes.pop();
/* Now fill in the entry. */
if (!res.is_object() || !res.has("channels"))
/* Skip. */
return select_by_popularity();
auto channels = res["channels"];
if (!channels.is_array())
return select_by_popularity();
for (auto i = size_t(0); i < channels.size(); ++i) {
auto channel = channels[i];
if ( !channel.is_object()
|| !channel.has("destination")
)
continue;
auto destination = channel["destination"];
if (!destination.is_string())
continue;
auto dest_s = std::string(destination);
entry.peers.emplace(Ln::NodeId(dest_s));
}
/* ***Finally*** determine if we should select
* this entry. */
wsum += entry.peers.size();
/* If fewer are selected than max proposals, go extend
* it. */
if (selected.size() < max_proposals) {
selected.emplace_back(std::move(entry));
return select_by_popularity();
}
/* Otherwise see if we should replace. */
auto dist = std::uniform_real_distribution<double>(
0, 1
);
auto p = double(entry.peers.size()) / wsum;
auto j = dist(Boss::random_engine);
if (j <= p) {
/* Randomly replace an existing selection. */
auto dist_i = std::uniform_int_distribution<size_t>(
0, selected.size() - 1
);
auto i = dist_i(Boss::random_engine);
selected[i] = std::move(entry);
}
return select_by_popularity();
});
});
}
Ev::Io<void> complete_select_by_popularity() {
/* Generate a log. */
auto log = std::ostringstream();
log << "ChannelFinderByPopularity: "
<< "Random selection (by popularity): "
;
auto first = true;
for (auto const& s : selected) {
if (first)
first = false;
else
log << ", ";
log << s.node
<< " (" << s.peers.size() << " peers)"
;
}
return Boss::log( bus, Info
, "%s", log.str().c_str()
).then([this]() {
return try_connect();
});
}
/* Shuffles the peers of a particular selected node,
* then tries to connect each peer in sequence.
*/
class ConnectChecker {
private:
S::Bus& bus;
Boss::Mod::Rpc& rpc;
struct Impl {
Ln::NodeId node;
std::vector<Ln::NodeId> peers;
std::vector<Ln::NodeId>::const_iterator peer_it;
S::Bus* bus;
Boss::Mod::Rpc* rpc;
};
public:
ConnectChecker() =delete;
explicit
ConnectChecker( S::Bus& bus_
, Boss::Mod::Rpc& rpc_
) : bus(bus_)
, rpc(rpc_)
{ }
/* Functor. */
Ev::Io<bool> operator()(Popular p) {
auto self = std::make_shared<Impl>();
self->node = std::move(p.node);
std::copy( p.peers.begin(), p.peers.end()
, std::back_inserter(self->peers)
);
std::shuffle( self->peers.begin()
, self->peers.end()
, Boss::random_engine
);
self->peer_it = self->peers.begin();
self->bus = &bus;
self->rpc = &rpc;
return loop(std::move(self));
}
private:
static
Ev::Io<bool> loop(std::shared_ptr<Impl> self) {
if (self->peer_it == self->peers.end())
return Ev::lift(false);
/* FIXME: Use Connector object. */
auto params = Json::Out()
.start_object()
.field( "id"
, std::string(*self->peer_it)
)
.end_object()
;
return self->rpc->command("connect"
, params
).then([](Jsmn::Object _) {
return Ev::lift(true);
}).catching<RpcError>([](RpcError const& _) {
return Ev::lift(false);
}).then([self](bool success) {
/* If succeeded, send proposal and exit
* loop. */
if (success) {
return self->bus->raise(Msg::ProposeChannelCandidates{
*self->peer_it,
self->node
}).then([]() {
return Ev::lift(true);
});
} else {
/* Keep looping. */
++self->peer_it;
return loop(self);
}
});
}
};
size_t proposals_made;
Ev::Io<void> try_connect() {
/* Now we try to connect to each of the peers
* of each of the selected nodes.
* If we manage to connect to one of the peers,
* we propose that peer and set the popular node
* as the patron.
*
* We go over each of the selected nodes by Ev::map,
* which runs all the selected nodes in parallel.
*/
return Ev::map( ConnectChecker(bus, *rpc)
, std::move(selected)
).then([this](std::vector<bool> results) {
/* Count number of true. */
proposals_made = 0;
for (auto const& flag : results)
if (flag)
++proposals_made;
return completed_solicit();
});
}
Ev::Io<void> completed_solicit() {
return Ev::yield().then([this]() {
if (proposals_made != 0)
return Boss::log( bus, Info
, "ChannelFinderByPopularity: "
"Proposed %zu nodes to "
"channel to, finished."
, proposals_made
);
else
return Boss::log( bus, Warn
, "ChannelFinderByPopularity: "
"No nodes were proposed."
);
}).then([this]() {
return signal_task_completion(proposals_made == 0);
});
}
Ev::Io<void> signal_task_completion(bool failed) {
running = false;
return bus.raise(Msg::TaskCompletion{
"ChannelFinderByPopularity", this_ptr, failed
});
}
public:
Impl( S::Bus& bus_
, Boss::Mod::Waiter& waiter_
, void* this_ptr_
) : bus(bus_)
, waiter(waiter_)
, this_ptr(this_ptr_)
, rpc(nullptr)
, running(false)
{ start(); }
};
ChannelFinderByPopularity::ChannelFinderByPopularity
( S::Bus& bus
, Boss::Mod::Waiter& waiter
) : pimpl(Util::make_unique<Impl>(bus, waiter, this)) { }
ChannelFinderByPopularity::ChannelFinderByPopularity
( ChannelFinderByPopularity&& o
) : pimpl(std::move(o.pimpl)) { }
ChannelFinderByPopularity::~ChannelFinderByPopularity() { }
}}