Quality: Rewrite OpenTSDB to use Boost ASIO and I/O engine

The connection handling and code isn't really good, but not
really actively maintained either.

Besides that, the "telnet" method doesn't allow for TLS,
this needs a general rewrite against their HTTP API.

I've also added function documentation where applicable.

lib/perfdata/opentsdbwriter.cpp

@@ -28,6 +28,9 @@ REGISTER_TYPE(OpenTsdbWriter);
 
 REGISTER_STATSFUNCTION(OpenTsdbWriter, &OpenTsdbWriter::StatsFunc);
 
+/*
+ * Enable HA capabilities once the config object is loaded.
+ */
 void OpenTsdbWriter::OnConfigLoaded()
 {
 	ObjectImpl<OpenTsdbWriter>::OnConfigLoaded();
@@ -42,17 +45,27 @@ void OpenTsdbWriter::OnConfigLoaded()
 	}
 }
 
+/**
+ * Feature stats interface
+ *
+ * @param status Key value pairs for feature stats
+ */
 void OpenTsdbWriter::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr&)
 {
 	DictionaryData nodes;
 
 	for (const OpenTsdbWriter::Ptr& opentsdbwriter : ConfigType::GetObjectsByType<OpenTsdbWriter>()) {
-		nodes.emplace_back(opentsdbwriter->GetName(), 1); //add more stats
+		nodes.emplace_back(opentsdbwriter->GetName(), new Dictionary({
+			{ "connected", opentsdbwriter->GetConnected() }
+		}));
 	}
 
 	status->Set("opentsdbwriter", new Dictionary(std::move(nodes)));
 }
 
+/**
+ * Resume is equivalent to Start, but with HA capabilities to resume at runtime.
+ */
 void OpenTsdbWriter::Resume()
 {
 	ObjectImpl<OpenTsdbWriter>::Resume();
@@ -69,7 +82,9 @@ void OpenTsdbWriter::Resume()
 	Service::OnNewCheckResult.connect(std::bind(&OpenTsdbWriter::CheckResultHandler, this, _1, _2));
 }
 
-/* Pause is equivalent to Stop, but with HA capabilities to resume at runtime. */
+/**
+ * Pause is equivalent to Stop, but with HA capabilities to resume at runtime.
+ */
 void OpenTsdbWriter::Pause()
 {
 	m_ReconnectTimer.reset();
@@ -77,33 +92,54 @@ void OpenTsdbWriter::Pause()
 	Log(LogInformation, "OpentsdbWriter")
 		<< "'" << GetName() << "' paused.";
 
+	m_Stream->close();
+
+	SetConnected(false);
+
 	ObjectImpl<OpenTsdbWriter>::Pause();
 }
 
+/**
+ * Reconnect handler called by the timer.
+ * Handles TLS
+ */
 void OpenTsdbWriter::ReconnectTimerHandler()
 {
 	if (IsPaused())
 		return;
 
-	if (m_Stream)
-		return;
+	SetShouldConnect(true);
 
-	TcpSocket::Ptr socket = new TcpSocket();
+	if (GetConnected())
+		return;
 
 	Log(LogNotice, "OpenTsdbWriter")
 		<< "Reconnect to OpenTSDB TSD on host '" << GetHost() << "' port '" << GetPort() << "'.";
 
+	/*
+	 * We're using telnet as input method. Future PRs may change this into using the HTTP API.
+	 * http://opentsdb.net/docs/build/html/user_guide/writing/index.html#telnet
+	 */
+
+	m_Stream = std::make_shared<AsioTcpStream>(IoEngine::Get().GetIoService());
+
 	try {
-		socket->Connect(GetHost(), GetPort());
-	} catch (std::exception&) {
-		Log(LogCritical, "OpenTsdbWriter")
-			<< "Can't connect to OpenTSDB TSD on host '" << GetHost() << "' port '" << GetPort() << "'.";
-		return;
+		icinga::Connect(m_Stream->lowest_layer(), GetHost(), GetPort());
+	} catch (const std::exception& ex) {
+		Log(LogWarning, "OpenTsdbWriter")
+			<< "Can't connect to OpenTSDB on host '" << GetHost() << "' port '" << GetPort() << ".'";
 	}
 
-	m_Stream = new NetworkStream(socket);
+	SetConnected(true);
 }
 
+/**
+ * Registered check result handler processing data.
+ * Calculates tags from the config.
+ *
+ * @param checkable Host/service object
+ * @param cr Check result
+ */
 void OpenTsdbWriter::CheckResultHandler(const Checkable::Ptr& checkable, const CheckResult::Ptr& cr)
 {
 	if (IsPaused())
@@ -165,6 +201,15 @@ void OpenTsdbWriter::CheckResultHandler(const Checkable::Ptr& checkable, const C
 	SendMetric(checkable, metric + ".execution_time", tags, cr->CalculateExecutionTime(), ts);
 }
 
+/**
+ * Parse and send performance data metrics to OpenTSDB
+ *
+ * @param checkable Host/service object
+ * @param metric Full metric name
+ * @param tags Tag key pairs
+ * @param cr Check result containing performance data
+ * @param ts Timestamp when the check result was received
+ */
 void OpenTsdbWriter::SendPerfdata(const Checkable::Ptr& checkable, const String& metric,
 	const std::map<String, String>& tags, const CheckResult::Ptr& cr, double ts)
 {
@@ -209,6 +254,15 @@ void OpenTsdbWriter::SendPerfdata(const Checkable::Ptr& checkable, const String&
 	}
 }
 
+/**
+ * Send given metric to OpenTSDB
+ *
+ * @param checkable Host/service object
+ * @param metric Full metric name
+ * @param tags Tag key pairs
+ * @param value Floating point metric value
+ * @param ts Timestamp where the metric was received from the check result
+ */
 void OpenTsdbWriter::SendMetric(const Checkable::Ptr& checkable, const String& metric,
 	const std::map<String, String>& tags, double value, double ts)
 {
@@ -220,7 +274,7 @@ void OpenTsdbWriter::SendMetric(const Checkable::Ptr& checkable, const String& m
 
 	std::ostringstream msgbuf;
 	/*
-	 * must be (http://opentsdb.net/docs/build/html/user_guide/writing.html)
+	 * must be (http://opentsdb.net/docs/build/html/user_guide/query/timeseries.html)
 	 * put <metric> <timestamp> <value> <tagk1=tagv1[ tagk2=tagv2 ...tagkN=tagvN]>
 	 * "tags" must include at least one tag, we use "host=HOSTNAME"
 	 */
@@ -235,21 +289,27 @@ void OpenTsdbWriter::SendMetric(const Checkable::Ptr& checkable, const String& m
 
 	ObjectLock olock(this);
 
-	if (!m_Stream)
+	if (!GetConnected())
 		return;
 
 	try {
-		m_Stream->Write(put.CStr(), put.GetLength());
+		Log(LogDebug, "OpenTsdbWriter")
+			<< "Checkable '" << checkable->GetName() << "' sending message '" << put << "'.";
+
+		boost::asio::write(*m_Stream, boost::asio::buffer(msgbuf.str()));
+		m_Stream->flush();
 	} catch (const std::exception& ex) {
 		Log(LogCritical, "OpenTsdbWriter")
-			<< "Cannot write to OpenTSDB TSD on host '" << GetHost() << "' port '" << GetPort() + "'.";
-
-		m_Stream.reset();
+			<< "Cannot write to TCP socket on host '" << GetHost() << "' port '" << GetPort() << "'.";
 	}
 }
 
-/* for metric and tag name rules, see
- * http://opentsdb.net/docs/build/html/user_guide/writing.html#metrics-and-tags
+/**
+ * Escape tags for OpenTSDB
+ * http://opentsdb.net/docs/build/html/user_guide/query/timeseries.html#precisions-on-metrics-and-tags
+ *
+ * @param str Tag name
+ * @return Escaped tag
  */
 String OpenTsdbWriter::EscapeTag(const String& str)
 {
@@ -261,6 +321,13 @@ String OpenTsdbWriter::EscapeTag(const String& str)
 	return result;
 }
 
+/**
+ * Escape metric name for OpenTSDB
+ * http://opentsdb.net/docs/build/html/user_guide/query/timeseries.html#precisions-on-metrics-and-tags
+ *
+ * @param str Metric name
+ * @return Escaped metric
+ */
 String OpenTsdbWriter::EscapeMetric(const String& str)
 {
 	String result = str;
@@ -271,4 +338,4 @@ String OpenTsdbWriter::EscapeMetric(const String& str)
 	boost::replace_all(result, ":", "_");
 
 	return result;
-}
+}

lib/perfdata/opentsdbwriter.hpp

@@ -32,7 +32,7 @@ protected:
 	void Pause() override;
 
 private:
-	Stream::Ptr m_Stream;
+	std::shared_ptr<AsioTcpStream> m_Stream;
 
 	Timer::Ptr m_ReconnectTimer;
 

lib/perfdata/opentsdbwriter.ti

@@ -20,6 +20,11 @@ class OpenTsdbWriter : ConfigObject
 	[config] bool enable_ha {
 		default {{{ return false; }}}
 	};
+
+	[no_user_modify] bool connected;
+	[no_user_modify] bool should_connect {
+		default {{{ return true; }}}
+	};
 };
 
 }