VILLASnode/lib/nodes/api.cpp

/* Node type: Universal Data-exchange API (v2).
 *
 * @see https://github.com/ERIGrid2/JRA-3.1-api
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <vector>

#include <villas/api/universal.hpp>
#include <villas/exceptions.hpp>
#include <villas/nodes/api.hpp>

using namespace villas;
using namespace villas::node;
using namespace villas::node::api::universal;

APINode::APINode(const uuid_t &id, const std::string &name)
    : Node(id, name), read(), write() {
  int ret;
  auto dirs = std::vector{&read, &write};

  for (auto dir : dirs) {
    ret = pthread_mutex_init(&dir->mutex, nullptr);
    if (ret)
      throw RuntimeError("failed to initialize mutex");

    ret = pthread_cond_init(&dir->cv, nullptr);
    if (ret)
      throw RuntimeError("failed to initialize mutex");
  }
}

int APINode::prepare() {
  auto signals_in = getInputSignals(false);

  read.sample = sample_alloc_mem(signals_in->size());
  if (!read.sample)
    throw MemoryAllocationError();

  write.sample = sample_alloc_mem(64);
  if (!write.sample)
    throw MemoryAllocationError();

  unsigned j = 0;
  for (auto sig : *signals_in)
    read.sample->data[j++] = sig->init;

  read.sample->length = j;
  read.sample->signals = signals_in;

  return Node::prepare();
}

int APINode::check() {
  for (auto &ch : read.channels) {
    if (ch->payload != PayloadType::SAMPLES)
      return -1;
  }

  for (auto &ch : write.channels) {
    if (ch->payload != PayloadType::SAMPLES)
      return -1;
  }

  return 0;
}

int APINode::_read(struct Sample *smps[], unsigned cnt) {
  assert(cnt == 1);

  pthread_cond_wait(&read.cv, &read.mutex);

  sample_copy(smps[0], read.sample);

  return 1;
}

int APINode::_write(struct Sample *smps[], unsigned cnt) {
  assert(cnt == 1);

  sample_copy(write.sample, smps[0]);

  pthread_cond_signal(&write.cv);

  return 1;
}

int APINode::parse(json_t *json) {
  int ret = Node::parse(json);
  if (ret)
    return ret;

  json_t *json_signals_in = nullptr;
  json_t *json_signals_out = nullptr;

  json_error_t err;
  ret = json_unpack_ex(json, &err, 0, "{ s?: { s?: o }, s?: { s?: o } }", "in",
                       "signals", &json_signals_in, "out", "signals",
                       &json_signals_out);
  if (ret)
    throw ConfigError(json, err, "node-config-node-api");

  if (json_signals_in)
    read.channels.parse(json_signals_in, false, true);

  if (json_signals_out)
    write.channels.parse(json_signals_out, true, false);

  return 0;
}

// Register node
static char n[] = "api";
static char d[] = "A node providing a HTTP REST interface";
static NodePlugin<APINode, n, d,
                  (int)NodeFactory::Flags::SUPPORTS_READ |
                      (int)NodeFactory::Flags::SUPPORTS_WRITE,
                  1>
    p;