Initial commit

utils.cc

@@ -0,0 +1,75 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "utils.h"
+
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "log.h"
+
+static const std::string host_name = []() {
+  char host[256];
+  gethostname(host, sizeof(host));
+  const std::string h(host);
+  size_t k = h.find('.');
+  if (k == std::string::npos) return h;
+  return h.substr(0, k);
+}();
+
+double TimeInSeconds() {
+  struct timeval tv;
+  gettimeofday(&tv, nullptr);
+  return ((tv.tv_sec * 1e6) + tv.tv_usec) / 1e6;
+}
+
+std::string Json(const std::string& field, int v) {
+  return "\"" + field + "\": " + std::to_string(v);
+}
+
+std::string Json(const std::string& field, uint64_t v) {
+  return "\"" + field + "\": " + std::to_string(v);
+}
+
+std::string Json(const std::string& field, double v) {
+  return "\"" + field + "\": " + std::to_string(v);
+}
+
+std::string JsonBool(const std::string& field, bool v) {
+  return "\"" + field + "\": " + (v ? "true" : "false");
+}
+
+std::string Json(const std::string& field, const std::string& v) {
+  return "\"" + field + "\": \"" + v + "\"";
+}
+
+std::string JsonRecord(const std::string& name, const std::string& v) {
+  return "\"" + name + "\": { " + v + " }";
+}
+
+// Emits null field.
+std::string JsonNull(const std::string& field) {
+  return "\"" + field + "\": null";
+}
+
+// Returns host and timestamp fields. ToDo: probably add a run id.
+std::string JTag() {
+  const uint64_t t = TimeInSeconds() * 1e6;
+  return Json("host", host_name) + ", " + Json("t_us", t);
+}
+
+// Emits a run status record.
+std::string Jstat(const std::string& v) {
+  return "{ " + JsonRecord("stat", v) + ", " + JTag() + " }";
+}