This directory contains an idiomatic C++ client library for interacting with Cloud BigQuery.
While this library is GA, please note that the Google Cloud C++ client libraries do not follow Semantic Versioning.
The quickstart/ directory contains a minimal environment to get started using this client library in a larger project. The following “Hello World” program is used in this quickstart, and should give you a taste of this library.
For detailed instructions on how to build and install this library, see the top-level README.
#include "google/cloud/bigquery/storage/v1/bigquery_read_client.h"
#include <iostream>
namespace {
void ProcessRowsInAvroFormat(
::google::cloud::bigquery::storage::v1::AvroSchema const&,
::google::cloud::bigquery::storage::v1::AvroRows const&) {
// Code to deserialize avro rows should be added here.
}
} // namespace
int main(int argc, char* argv[]) try {
if (argc != 3) {
std::cerr << "Usage: " << argv[0] << " <project-id> <table-name>\n";
return 1;
}
// project_name should be in the format "projects/<your-gcp-project>"
std::string const project_name = "projects/" + std::string(argv[1]);
// table_name should be in the format:
// "projects/<project-table-resides-in>/datasets/<dataset-table_resides-in>/tables/<table
// name>" The project values in project_name and table_name do not have to be
// identical.
std::string const table_name = argv[2];
// Create a namespace alias to make the code easier to read.
namespace bigquery_storage = ::google::cloud::bigquery_storage_v1;
constexpr int kMaxReadStreams = 1;
// Create the ReadSession.
auto client = bigquery_storage::BigQueryReadClient(
bigquery_storage::MakeBigQueryReadConnection());
::google::cloud::bigquery::storage::v1::ReadSession read_session;
read_session.set_data_format(
google::cloud::bigquery::storage::v1::DataFormat::AVRO);
read_session.set_table(table_name);
auto session =
client.CreateReadSession(project_name, read_session, kMaxReadStreams);
if (!session) throw std::move(session).status();
// Read rows from the ReadSession.
constexpr int kRowOffset = 0;
auto read_rows = client.ReadRows(session->streams(0).name(), kRowOffset);
std::int64_t num_rows = 0;
for (auto const& row : read_rows) {
if (row.ok()) {
num_rows += row->row_count();
ProcessRowsInAvroFormat(session->avro_schema(), row->avro_rows());
}
}
std::cout << num_rows << " rows read from table: " << table_name << "\n";
return 0;
} catch (google::cloud::Status const& status) {
std::cerr << "google::cloud::Status thrown: " << status << "\n";
return 1;
}
.h files