Adding ZMQ/Pub support for txpool_add and chain_main events

1 files changed, 478 insertions, 0 deletions

diff --git a/src/rpc/zmq_pub.cpp b/src/rpc/zmq_pub.cpp
new file mode 100644
index 000000000..0dffffac6
--- /dev/null
+++ b/src/rpc/zmq_pub.cpp
@@ -0,0 +1,478 @@
+// Copyright (c) 2020, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "zmq_pub.h"
+
+#include <algorithm>
+#include <boost/range/adaptor/filtered.hpp>
+#include <boost/range/adaptor/transformed.hpp>
+#include <boost/thread/locks.hpp>
+#include <cassert>
+#include <cstdint>
+#include <cstring>
+#include <rapidjson/document.h>
+#include <rapidjson/stringbuffer.h>
+#include <rapidjson/writer.h>
+#include <stdexcept>
+#include <string>
+#include <utility>
+
+#include "common/expect.h"
+#include "crypto/crypto.h"
+#include "cryptonote_basic/cryptonote_format_utils.h"
+#include "cryptonote_basic/events.h"
+#include "misc_log_ex.h"
+#include "serialization/json_object.h"
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "net.zmq"
+
+namespace
+{
+  constexpr const char txpool_signal[] = "tx_signal";
+
+  using chain_writer =  void(epee::byte_stream&, std::uint64_t, epee::span<const cryptonote::block>);
+  using txpool_writer = void(epee::byte_stream&, epee::span<const cryptonote::txpool_event>);
+
+  template<typename F>
+  struct context
+  {
+    char const* const name;
+    F* generate_pub;
+  };
+
+  template<typename T>
+  bool operator<(const context<T>& lhs, const context<T>& rhs) noexcept
+  {
+    return std::strcmp(lhs.name, rhs.name) < 0;
+  }
+
+  template<typename T>
+  bool operator<(const context<T>& lhs, const boost::string_ref rhs) noexcept
+  {
+    return lhs.name < rhs;
+  }
+
+  struct is_valid
+  {
+    bool operator()(const cryptonote::txpool_event& event) const noexcept
+    {
+      return event.res;
+    }
+  };
+
+  template<typename T, std::size_t N>
+  void verify_sorted(const std::array<context<T>, N>& elems, const char* name)
+  {
+    auto unsorted = std::is_sorted_until(elems.begin(), elems.end());
+    if (unsorted != elems.end())
+      throw std::logic_error{name + std::string{" array is not properly sorted, see: "} + unsorted->name};
+  }
+
+  void write_header(epee::byte_stream& buf, const boost::string_ref name)
+  {
+    buf.write(name.data(), name.size());
+    buf.put(':');
+  }
+
+  //! \return `name:...` where `...` is JSON and `name` is directly copied (no quotes - not JSON).
+  template<typename T>
+  void json_pub(epee::byte_stream& buf, const T value)
+  {
+    rapidjson::Writer<epee::byte_stream> dest{buf};
+    using cryptonote::json::toJsonValue;
+    toJsonValue(dest, value);
+  }
+
+  //! Object for "minimal" block serialization
+  struct minimal_chain
+  {
+    const std::uint64_t height;
+    const epee::span<const cryptonote::block> blocks;
+  };
+
+  //! Object for "minimal" tx serialization
+  struct minimal_txpool
+  {
+    const cryptonote::transaction& tx;
+  };
+
+  void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const minimal_chain self)
+  {
+    namespace adapt = boost::adaptors;
+
+    const auto to_block_id = [](const cryptonote::block& bl)
+    {
+      crypto::hash id;
+      if (!get_block_hash(bl, id))
+        MERROR("ZMQ/Pub failure: get_block_hash");
+      return id;
+    };
+
+    assert(!self.blocks.empty()); // checked in zmq_pub::send_chain_main
+
+    dest.StartObject();
+    INSERT_INTO_JSON_OBJECT(dest, first_height, self.height);
+    INSERT_INTO_JSON_OBJECT(dest, first_prev_id, self.blocks[0].prev_id);
+    INSERT_INTO_JSON_OBJECT(dest, ids, (self.blocks | adapt::transformed(to_block_id)));
+    dest.EndObject();
+  }
+
+  void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const minimal_txpool self)
+  {
+    crypto::hash id{};
+    std::size_t blob_size = 0;
+    if (!get_transaction_hash(self.tx, id, blob_size))
+    {
+      MERROR("ZMQ/Pub failure: get_transaction_hash");
+      return;
+    }
+
+    dest.StartObject();
+    INSERT_INTO_JSON_OBJECT(dest, id, id);
+    INSERT_INTO_JSON_OBJECT(dest, blob_size, blob_size);
+    dest.EndObject();
+  }
+
+  void json_full_chain(epee::byte_stream& buf, const std::uint64_t height, const epee::span<const cryptonote::block> blocks)
+  {
+    json_pub(buf, blocks);
+  }
+
+  void json_minimal_chain(epee::byte_stream& buf, const std::uint64_t height, const epee::span<const cryptonote::block> blocks)
+  {
+    json_pub(buf, minimal_chain{height, blocks});
+  }
+
+  // boost::adaptors are in place "views" - no copy/move takes place
+  // moving transactions (via sort, etc.), is expensive!
+
+  void json_full_txpool(epee::byte_stream& buf, epee::span<const cryptonote::txpool_event> txes)
+  {
+    namespace adapt = boost::adaptors;
+    const auto to_full_tx = [](const cryptonote::txpool_event& event)
+    {
+      return event.tx;
+    };
+    json_pub(buf, (txes | adapt::filtered(is_valid{}) | adapt::transformed(to_full_tx)));
+  }
+
+  void json_minimal_txpool(epee::byte_stream& buf, epee::span<const cryptonote::txpool_event> txes)
+  {
+    namespace adapt = boost::adaptors;
+    const auto to_minimal_tx = [](const cryptonote::txpool_event& event)
+    {
+      return minimal_txpool{event.tx};
+    };
+    json_pub(buf, (txes | adapt::filtered(is_valid{}) | adapt::transformed(to_minimal_tx)));
+  }
+
+  constexpr const std::array<context<chain_writer>, 2> chain_contexts =
+  {{
+    {u8"json-full-chain_main", json_full_chain},
+    {u8"json-minimal-chain_main", json_minimal_chain}
+  }};
+
+  constexpr const std::array<context<txpool_writer>, 2> txpool_contexts =
+  {{
+    {u8"json-full-txpool_add", json_full_txpool},
+    {u8"json-minimal-txpool_add", json_minimal_txpool}
+  }};
+
+  template<typename T, std::size_t N>
+  epee::span<const context<T>> get_range(const std::array<context<T>, N>& contexts, const boost::string_ref value)
+  {
+    const auto not_prefix = [](const boost::string_ref lhs, const context<T>& rhs)
+    {
+      return !(boost::string_ref{rhs.name}.starts_with(lhs));
+    };
+
+    const auto lower = std::lower_bound(contexts.begin(), contexts.end(), value);
+    const auto upper = std::upper_bound(lower, contexts.end(), value, not_prefix);
+    return {lower, std::size_t(upper - lower)};
+  }
+
+  template<std::size_t N, typename T>
+  void add_subscriptions(std::array<std::size_t, N>& subs, const epee::span<const context<T>> range, context<T> const* const first)
+  {
+    assert(range.size() <= N);
+    assert(range.begin() - first <= N - range.size());
+
+    for (const auto& ctx : range)
+    {
+      const std::size_t i = std::addressof(ctx) - first;
+      subs[i] = std::min(std::numeric_limits<std::size_t>::max() - 1, subs[i]) + 1;
+    }
+  }
+
+  template<std::size_t N, typename T>
+  void remove_subscriptions(std::array<std::size_t, N>& subs, const epee::span<const context<T>> range, context<T> const* const first)
+  {
+    assert(range.size() <= N);
+    assert(range.begin() - first <= N - range.size());
+
+    for (const auto& ctx : range)
+    {
+      const std::size_t i = std::addressof(ctx) - first;
+      subs[i] = std::max(std::size_t(1), subs[i]) - 1;
+    }
+  }
+
+  template<std::size_t N, typename T, typename... U>
+  std::array<epee::byte_slice, N> make_pubs(const std::array<std::size_t, N>& subs, const std::array<context<T>, N>& contexts, U&&... args)
+  {
+    epee::byte_stream buf{};
+
+    std::size_t last_offset = 0;
+    std::array<std::size_t, N> offsets{{}};
+    for (std::size_t i = 0; i < N; ++i)
+    {
+      if (subs[i])
+      {
+        write_header(buf, contexts[i].name);
+        contexts[i].generate_pub(buf, std::forward<U>(args)...);
+        offsets[i] = buf.size() - last_offset;
+        last_offset = buf.size();
+      }
+    }
+
+    epee::byte_slice bytes{std::move(buf)};
+    std::array<epee::byte_slice, N> out;
+    for (std::size_t i = 0; i < N; ++i)
+      out[i] = bytes.take_slice(offsets[i]);
+
+    return out;
+  }
+
+  template<std::size_t N>
+  std::size_t send_messages(void* const socket, std::array<epee::byte_slice, N>& messages)
+  {
+    std::size_t count = 0;
+    for (epee::byte_slice& message : messages)
+    {
+      if (!message.empty())
+      {
+        const expect<void> sent = net::zmq::send(std::move(message), socket, ZMQ_DONTWAIT);
+        if (!sent)
+          MERROR("Failed to send ZMQ/Pub message: " << sent.error().message());
+        else
+          ++count;
+      }
+    }
+    return count;
+  }
+
+  expect<bool> relay_block_pub(void* const relay, void* const pub) noexcept
+  {
+    zmq_msg_t msg;
+    zmq_msg_init(std::addressof(msg));
+    MONERO_CHECK(net::zmq::retry_op(zmq_msg_recv, std::addressof(msg), relay, ZMQ_DONTWAIT));
+
+    const boost::string_ref payload{
+      reinterpret_cast<const char*>(zmq_msg_data(std::addressof(msg))),
+      zmq_msg_size(std::addressof(msg))
+    };
+
+    if (payload == txpool_signal)
+    {
+      zmq_msg_close(std::addressof(msg));
+      return false;
+    }
+
+    // forward block messages (serialized on P2P thread for now)
+    const expect<void> sent = net::zmq::retry_op(zmq_msg_send, std::addressof(msg), pub, ZMQ_DONTWAIT);
+    if (!sent)
+    {
+      zmq_msg_close(std::addressof(msg));
+      return sent.error();
+    }
+    return true;
+  }
+} // anonymous
+
+namespace cryptonote { namespace listener
+{
+
+zmq_pub::zmq_pub(void* context)
+  : relay_(),
+    chain_subs_{{0}},
+    txpool_subs_{{0}},
+    sync_()
+{
+  if (!context)
+    throw std::logic_error{"ZMQ context cannot be NULL"};
+
+  verify_sorted(chain_contexts, "chain_contexts");
+  verify_sorted(txpool_contexts, "txpool_contexts");
+
+  relay_.reset(zmq_socket(context, ZMQ_PAIR));
+  if (!relay_)
+    MONERO_ZMQ_THROW("Failed to create relay socket");
+  if (zmq_connect(relay_.get(), relay_endpoint()) != 0)
+    MONERO_ZMQ_THROW("Failed to connect relay socket");
+}
+
+zmq_pub::~zmq_pub()
+{}
+
+bool zmq_pub::sub_request(boost::string_ref message)
+{
+  if (!message.empty())
+  {
+    const char tag = message[0];
+    message.remove_prefix(1);
+
+    const auto chain_range = get_range(chain_contexts, message);
+    const auto txpool_range = get_range(txpool_contexts, message);
+
+    if (!chain_range.empty() || !txpool_range.empty())
+    {
+      MDEBUG("Client " << (tag ? "subscribed" : "unsubscribed") << " to " <<
+             chain_range.size() << " chain topic(s) and " << txpool_range.size() << " txpool topic(s)");
+
+      const boost::lock_guard<boost::mutex> lock{sync_};
+      switch (tag)
+      {
+      case 0:
+        remove_subscriptions(chain_subs_, chain_range, chain_contexts.begin());
+        remove_subscriptions(txpool_subs_, txpool_range, txpool_contexts.begin());
+        return true;
+      case 1:
+        add_subscriptions(chain_subs_, chain_range, chain_contexts.begin());
+        add_subscriptions(txpool_subs_, txpool_range, txpool_contexts.begin());
+        return true;
+      default:
+        break;
+      }
+    }
+  }
+  MERROR("Invalid ZMQ/Sub message");
+  return false;
+}
+
+bool zmq_pub::relay_to_pub(void* const relay, void* const pub)
+{
+  const expect<bool> relayed = relay_block_pub(relay, pub);
+  if (!relayed)
+  {
+    MERROR("Error relaying ZMQ/Pub: " << relayed.error().message());
+    return false;
+  }
+
+  if (!*relayed)
+  {
+    std::array<std::size_t, 2> subs;
+    std::vector<cryptonote::txpool_event> events;
+    {
+      const boost::lock_guard<boost::mutex> lock{sync_};
+      if (txes_.empty())
+        return false;
+
+      subs = txpool_subs_;
+      events = std::move(txes_.front());
+      txes_.pop_front();
+    }
+    auto messages = make_pubs(subs, txpool_contexts, epee::to_span(events));
+    send_messages(pub, messages);
+    MDEBUG("Sent txpool ZMQ/Pub");
+  }
+  else
+    MDEBUG("Sent chain_main ZMQ/Pub");
+
+  return true;
+}
+
+std::size_t zmq_pub::send_chain_main(const std::uint64_t height, const epee::span<const cryptonote::block> blocks)
+{
+  if (blocks.empty())
+    return 0;
+
+  /* Block format only sends one block at a time - multiple block notifications
+     are less common and only occur on rollbacks. */
+
+  boost::unique_lock<boost::mutex> guard{sync_};
+
+  const auto subs_copy = chain_subs_;
+  guard.unlock();
+
+  for (const std::size_t sub : subs_copy)
+  {
+    if (sub)
+    {
+      /* cryptonote_core/blockchain.cpp cannot "give" us the block like core
+         does for txpool events. Since copying the block is expensive anyway,
+         serialization is done right here on the p2p thread (for now). */
+
+        auto messages = make_pubs(subs_copy, chain_contexts, height, blocks);
+        guard.lock();
+        return send_messages(relay_.get(), messages);
+    }
+  }
+  return 0;
+}
+
+std::size_t zmq_pub::send_txpool_add(std::vector<txpool_event> txes)
+{
+  if (txes.empty())
+    return 0;
+
+  const boost::lock_guard<boost::mutex> lock{sync_};
+  for (const std::size_t sub : txpool_subs_)
+  {
+    if (sub)
+    {
+      const expect<void> sent = net::zmq::retry_op(zmq_send_const, relay_.get(), txpool_signal, sizeof(txpool_signal) - 1, ZMQ_DONTWAIT);
+      if (sent)
+        txes_.emplace_back(std::move(txes));
+      else
+        MERROR("ZMQ/Pub failure, relay queue error: " << sent.error().message());
+      return bool(sent);
+    }
+  }
+  return 0;
+}
+
+void zmq_pub::chain_main::operator()(const std::uint64_t height, epee::span<const cryptonote::block> blocks) const
+{
+  const std::shared_ptr<zmq_pub> self = self_.lock();
+  if (self)
+    self->send_chain_main(height, blocks);
+  else
+    MERROR("Unable to send ZMQ/Pub - ZMQ server destroyed");
+}
+
+void zmq_pub::txpool_add::operator()(std::vector<cryptonote::txpool_event> txes) const
+{
+  const std::shared_ptr<zmq_pub> self = self_.lock();
+  if (self)
+      self->send_txpool_add(std::move(txes));
+  else
+    MERROR("Unable to send ZMQ/Pub - ZMQ server destroyed");
+}
+
+}}