add a StatusWriter class hierarchy for writing member status updates

* Postgres Direct
* Redis
* BigTable

controller/BigTableStatusWriter.cpp

@@ -0,0 +1,98 @@
+#include "BigTableStatusWriter.hpp"
+
+#include <google/cloud/bigtable/mutations.h>
+#include <google/cloud/bigtable/row.h>
+#include <google/cloud/bigtable/table.h>
+
+namespace cbt = google::cloud::bigtable;
+
+namespace ZeroTier {
+
+const std::string nodeInfoColumnFamily = "node_info";
+const std::string checkInColumnFamily = "check_in";
+
+const std::string osColumn = "os";
+const std::string archColumn = "arch";
+const std::string versionColumn = "version";
+const std::string ipv4Column = "ipv4";
+const std::string ipv6Column = "ipv6";
+const std::string lastSeenColumn = "last_seen";
+
+BigTableStatusWriter::BigTableStatusWriter(
+	const std::string& project_id,
+	const std::string& instance_id,
+	const std::string& table_id)
+	: _project_id(project_id)
+	, _instance_id(instance_id)
+	, _table_id(table_id)
+{
+}
+
+BigTableStatusWriter::~BigTableStatusWriter()
+{
+	writePending();
+}
+
+void BigTableStatusWriter::updateNodeStatus(
+	const std::string& network_id,
+	const std::string& node_id,
+	const std::string& os,
+	const std::string& arch,
+	const std::string& version,
+	const InetAddress& address,
+	int64_t last_seen)
+{
+	std::lock_guard<std::mutex> l(_lock);
+	_pending.push_back({ network_id, node_id, os, arch, version, address, last_seen });
+	if (_pending.size() >= 100) {
+		writePending();
+	}
+}
+
+size_t BigTableStatusWriter::queueLength() const
+{
+	std::lock_guard<std::mutex> l(_lock);
+	return _pending.size();
+}
+
+void BigTableStatusWriter::writePending()
+{
+	std::vector<PendingStatusEntry> toWrite;
+	{
+		std::lock_guard<std::mutex> l(_lock);
+		toWrite.swap(_pending);
+	}
+	if (toWrite.empty()) {
+		return;
+	}
+
+	namespace cbt = google::cloud::bigtable;
+	cbt::Table table(cbt::MakeDataConnection(), cbt::TableResource(_project_id, _instance_id, _table_id));
+
+	cbt::BulkMutation bulk;
+	for (const auto& entry : toWrite) {
+		std::string row_key = entry.network_id + "#" + entry.node_id;
+		cbt::SingleRowMutation m(row_key);
+		m.emplace_back(cbt::SetCell(nodeInfoColumnFamily, osColumn, entry.os));
+		m.emplace_back(cbt::SetCell(nodeInfoColumnFamily, archColumn, entry.arch));
+		m.emplace_back(cbt::SetCell(nodeInfoColumnFamily, versionColumn, entry.version));
+		char buf[64] = { 0 };
+		if (entry.address.ss_family == AF_INET) {
+			m.emplace_back(cbt::SetCell(checkInColumnFamily, ipv4Column, entry.address.toString(buf)));
+		}
+		else if (entry.address.ss_family == AF_INET6) {
+			m.emplace_back(cbt::SetCell(checkInColumnFamily, ipv6Column, entry.address.toString(buf)));
+		}
+		int64_t ts = entry.last_seen;
+		m.emplace_back(cbt::SetCell(checkInColumnFamily, lastSeenColumn, std::move(ts)));
+		bulk.push_back(std::move(m));
+	}
+
+	std::vector<cbt::FailedMutation> failures = table.BulkApply(bulk);
+	for (auto const& r : failures) {
+		// Handle error (log it, retry, etc.)
+		std::cerr << "Error writing to BigTable: " << r.status() << "\n";
+	}
+}
+
+}	// namespace ZeroTier