1 files changed, 258 insertions, 0 deletions
diff --git a/exporting/pubsub/pubsub_publish.cc b/exporting/pubsub/pubsub_publish.cc
new file mode 100644
index 000000000..dc237cf22
--- /dev/null
+++ b/exporting/pubsub/pubsub_publish.cc
@@ -0,0 +1,258 @@
+// 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 responces
+ *
+ * @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 successfuly sent.
+ * @param sent_bytes report to a caller how many bytes was successfuly 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_impl::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;
+}