[WIP] Statsd exporter

exporters/statsd/include/opentelemetry/exporters/statsd/UnixDomainTransport.h

@@ -0,0 +1,75 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include "statsd_common.h"
+#include "opentelemetry/version.h"
+
+#include <string>
+
+#include <arpa/inet.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter {
+namespace statsd {
+namespace metrics {
+
+
+class UnixDomainClient 
+{
+
+UnixDomainClient(std::string path): socket_path_(path){}
+bool Initialize()
+{
+    server_socket_fd_ = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (server_socket_fd_ == -1) {
+        // log error
+        return false;
+    }
+    sockaddr_un remote;
+    remote.sun_family = AF_UNIX;
+    strncpy_s(remote.sun_path, sizeof(remote.sun_path), socket_path_.c_str(),
+                sizeof(remote.sun_path));
+    if (connect(server_socket_fd_, (sockaddr*)&remote, strlen(remote.sun_path) + sizeof(remote.sun_family)) == -1) {
+        //connect failed
+        ::close(server_socket_fd_);
+        server_socket_fd_ = 0;
+        return false;
+    }
+    //success
+    return true;
+}
+
+bool Send(const char* data, uint32_t size)
+{
+    auto bytes_left = size;
+    sizt_t num_bytes_sent;
+    while ((bytes_left > 0) && ((num_bytes_sent = ::send(server_socket_fd, buf, bytes_left, MSG_NOSIGNAL)) > 0)) {
+        bytes_left -= num_bytes_sent;
+        buf += num_bytes_sent;
+    }
+    return (bytes_left == 0); // success if all bytes sent
+}
+
+~UnixDomainClient()
+{
+    if (server_socket_fd_) {
+        ::close(server_socket_fd_);
+    }
+}
+
+private:
+std::string socket_path_;
+uint16_t server_socket_fd_ = 0;
+
+}
+}
+}
+}
+OPENTELEMETRY_END_NAMESPACE

exporters/statsd/include/opentelemetry/exporters/statsd/exporter.h

@@ -0,0 +1,61 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+
+#  include <iostream>
+#  include <string>
+#  include "opentelemetry/common/spin_lock_mutex.h"
+#  include "opentelemetry/sdk/metrics/data/metric_data.h"
+#  include "opentelemetry/sdk/metrics/instruments.h"
+#  include "opentelemetry/sdk/metrics/metric_exporter.h"
+#  include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace metrics
+{
+struct StatsdExporterOptions
+{
+    std::string unixdomain_path = "'/var/run/stats.sock";
+};
+
+class StatsdExporter : public opentelemetry::sdk::metrics::MetricExporter
+{
+public:
+    explicit StatsdExporter(const StatsdExporterOptions &options);
+
+    /**
+     * Export
+     * @param data metrics data
+     */
+    sdk::common::ExportResult Export(const sdk::metrics::ResourceMetrics &data) noexcept override;
+
+    /**
+    * Force flush the exporter.
+    */
+    bool ForceFlush(
+      std::chrono::microseconds timeout = (std::chrono::microseconds::max)()) noexcept override;
+
+    /**
+    * Shut down the exporter.
+    * @param timeout an optional timeout, the default timeout of 0 means that no
+    * timeout is applied.
+    * @return return the status of this operation
+    */
+    bool Shutdown(std::chrono::microseconds timeout = std::chrono::microseconds(0)) noexcept override;
+
+private:
+    bool is_shutdown_ = false;
+    mutable opentelemetry::common::SpinLockMutex lock_;
+    UnixDomainTransport transport_;
+
+    };
+
+
+}
+}
+OPENTELEMETRY_END_NAMESPACE
+#endif

exporters/statsd/include/opentelemetry/exporters/statsd/statsd_common.h

@@ -0,0 +1,16 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include <string>
+#pragma once
+
+#ifndef strncpy_s
+#define strncpy_s(dest, destsz, src, count)                                    \
+  strncpy(dest, src, (destsz <= count) ? destsz : count)
+#endif
+
+#ifndef NO_OTEL_STATSD_DEBUG
+#define DEBUG_MSG(...) printf(__VA_ARGS__)
+#else
+#define DEBUG_MSG(...)
+#endif