src/exporting/pubsub/pubsub_publish.cc
// SPDX-License-Identifier: GPL-3.0-or-later
#include <google/pubsub/v1/pubsub.grpc.pb.h>
#include <grpcpp/grpcpp.h>
#include <stdexcept>
#include "pubsub_publish.h"
#define EVENT_CHECK_TIMEOUT 50
struct response {
grpc::ClientContext *context;
google::pubsub::v1::PublishResponse *publish_response;
size_t tag;
grpc::Status *status;
size_t published_metrics;
size_t published_bytes;
};
static inline void copy_error_message(char *error_message_dst, const char *error_message_src)
{
std::strncpy(error_message_dst, error_message_src, ERROR_LINE_MAX);
error_message_dst[ERROR_LINE_MAX] = '\0';
}
/**
* Initialize a Pub/Sub client and a data structure for responses.
*
* @param pubsub_specific_data_p a pointer to a structure with instance-wide data.
* @param error_message report error message to a caller.
* @param destination a Pub/Sub service endpoint.
* @param credentials_file a full path for a file with google application credentials.
* @param project_id a project ID.
* @param topic_id a topic ID.
* @return Returns 0 on success, 1 on failure.
*/
int pubsub_init(
void *pubsub_specific_data_p, char *error_message, const char *destination, const char *credentials_file,
const char *project_id, const char *topic_id)
{
struct pubsub_specific_data *connector_specific_data = (struct pubsub_specific_data *)pubsub_specific_data_p;
try {
setenv("GOOGLE_APPLICATION_CREDENTIALS", credentials_file, 0);
std::shared_ptr<grpc::ChannelCredentials> credentials = grpc::GoogleDefaultCredentials();
if (credentials == nullptr) {
copy_error_message(error_message, "Can't load credentials");
return 1;
}
std::shared_ptr<grpc::Channel> channel = grpc::CreateChannel(destination, credentials);
google::pubsub::v1::Publisher::Stub *stub = new google::pubsub::v1::Publisher::Stub(channel);
if (!stub) {
copy_error_message(error_message, "Can't create a publisher stub");
return 1;
}
connector_specific_data->stub = stub;
google::pubsub::v1::PublishRequest *request = new google::pubsub::v1::PublishRequest;
connector_specific_data->request = request;
((google::pubsub::v1::PublishRequest *)(connector_specific_data->request))
->set_topic(std::string("projects/") + project_id + "/topics/" + topic_id);
grpc::CompletionQueue *cq = new grpc::CompletionQueue;
connector_specific_data->completion_queue = cq;
connector_specific_data->responses = new std::list<struct response>;
return 0;
} catch (std::exception const &ex) {
std::string em(std::string("Standard exception raised: ") + ex.what());
copy_error_message(error_message, em.c_str());
return 1;
}
return 0;
}
/**
* Clean the PubSub connector instance specific data
*/
void pubsub_cleanup(void *pubsub_specific_data_p)
{
struct pubsub_specific_data *connector_specific_data = (struct pubsub_specific_data *)pubsub_specific_data_p;
std::list<struct response> *responses = (std::list<struct response> *)connector_specific_data->responses;
std::list<struct response>::iterator response;
for (response = responses->begin(); response != responses->end(); ++response) {
// TODO: If we do this, there are a huge amount of possibly lost records. We need to find a right way of
// cleaning up contexts
// delete response->context;
delete response->publish_response;
delete response->status;
}
delete responses;
((grpc::CompletionQueue *)connector_specific_data->completion_queue)->Shutdown();
delete (grpc::CompletionQueue *)connector_specific_data->completion_queue;
delete (google::pubsub::v1::PublishRequest *)connector_specific_data->request;
delete (google::pubsub::v1::Publisher::Stub *)connector_specific_data->stub;
// TODO: Find how to shutdown grpc gracefully. grpc_shutdown() doesn't seem to work.
// grpc_shutdown();
return;
}
/**
* Add data to a Pub/Sub request message.
*
* @param pubsub_specific_data_p a pointer to a structure with instance-wide data.
* @param data a text buffer with metrics.
* @return Returns 0 on success, 1 on failure.
*/
int pubsub_add_message(void *pubsub_specific_data_p, char *data)
{
struct pubsub_specific_data *connector_specific_data = (struct pubsub_specific_data *)pubsub_specific_data_p;
try {
google::pubsub::v1::PubsubMessage *message =
((google::pubsub::v1::PublishRequest *)(connector_specific_data->request))->add_messages();
if (!message)
return 1;
message->set_data(data);
} catch (std::exception const &ex) {
return 1;
}
return 0;
}
/**
* Send data to the Pub/Sub service
*
* @param pubsub_specific_data_p a pointer to a structure with client and request outcome information.
* @param error_message report error message to a caller.
* @param buffered_metrics the number of metrics we are going to send.
* @param buffered_bytes the number of bytes we are going to send.
* @return Returns 0 on success, 1 on failure.
*/
int pubsub_publish(void *pubsub_specific_data_p, char *error_message, size_t buffered_metrics, size_t buffered_bytes)
{
struct pubsub_specific_data *connector_specific_data = (struct pubsub_specific_data *)pubsub_specific_data_p;
try {
grpc::ClientContext *context = new grpc::ClientContext;
std::unique_ptr<grpc::ClientAsyncResponseReader<google::pubsub::v1::PublishResponse> > rpc(
((google::pubsub::v1::Publisher::Stub *)(connector_specific_data->stub))
->AsyncPublish(
context, (*(google::pubsub::v1::PublishRequest *)(connector_specific_data->request)),
((grpc::CompletionQueue *)(connector_specific_data->completion_queue))));
struct response response;
response.context = context;
response.publish_response = new google::pubsub::v1::PublishResponse;
response.tag = connector_specific_data->last_tag++;
response.status = new grpc::Status;
response.published_metrics = buffered_metrics;
response.published_bytes = buffered_bytes;
rpc->Finish(response.publish_response, response.status, (void *)response.tag);
((google::pubsub::v1::PublishRequest *)(connector_specific_data->request))->clear_messages();
((std::list<struct response> *)(connector_specific_data->responses))->push_back(response);
} catch (std::exception const &ex) {
std::string em(std::string("Standard exception raised: ") + ex.what());
copy_error_message(error_message, em.c_str());
return 1;
}
return 0;
}
/**
* Get results from service responses
*
* @param pubsub_specific_data_p a pointer to a structure with instance-wide data.
* @param error_message report error message to a caller.
* @param sent_metrics report to a caller how many metrics was successfully sent.
* @param sent_bytes report to a caller how many bytes was successfully sent.
* @param lost_metrics report to a caller how many metrics was lost during transmission.
* @param lost_bytes report to a caller how many bytes was lost during transmission.
* @return Returns 0 if all data was sent successfully, 1 when data was lost on transmission.
*/
int pubsub_get_result(
void *pubsub_specific_data_p, char *error_message,
size_t *sent_metrics, size_t *sent_bytes, size_t *lost_metrics, size_t *lost_bytes)
{
struct pubsub_specific_data *connector_specific_data = (struct pubsub_specific_data *)pubsub_specific_data_p;
std::list<struct response> *responses = (std::list<struct response> *)connector_specific_data->responses;
grpc::CompletionQueue::NextStatus next_status;
*sent_metrics = 0;
*sent_bytes = 0;
*lost_metrics = 0;
*lost_bytes = 0;
try {
do {
std::list<struct response>::iterator response;
void *got_tag;
bool ok = false;
auto deadline = std::chrono::system_clock::now() + std::chrono::milliseconds(50);
next_status = (*(grpc::CompletionQueue *)(connector_specific_data->completion_queue))
.AsyncNext(&got_tag, &ok, deadline);
if (next_status == grpc::CompletionQueue::GOT_EVENT) {
for (response = responses->begin(); response != responses->end(); ++response) {
if ((void *)response->tag == got_tag)
break;
}
if (response == responses->end()) {
copy_error_message(error_message, "Cannot get Pub/Sub response");
return 1;
}
if (ok && response->publish_response->message_ids_size()) {
*sent_metrics += response->published_metrics;
*sent_bytes += response->published_bytes;
} else {
*lost_metrics += response->published_metrics;
*lost_bytes += response->published_bytes;
response->status->error_message().copy(error_message, ERROR_LINE_MAX);
error_message[ERROR_LINE_MAX] = '\0';
}
delete response->context;
delete response->publish_response;
delete response->status;
responses->erase(response);
}
if (next_status == grpc::CompletionQueue::SHUTDOWN) {
copy_error_message(error_message, "Completion queue shutdown");
return 1;
}
} while (next_status == grpc::CompletionQueue::GOT_EVENT);
} catch (std::exception const &ex) {
std::string em(std::string("Standard exception raised: ") + ex.what());
copy_error_message(error_message, em.c_str());
return 1;
}
if (*lost_metrics) {
return 1;
}
return 0;
}