Add version to the Stackdriver agent label. (#188)

* Add version to the Stackdriver agent label.

* Update version to 0.3.0-dev.

* Change artifact name to version and make it package only.

Author: Bogdan Drutu

opencensus/common/BUILD

@@ -0,0 +1,28 @@
+# OpenCensus C++ Common library.
+# See ../../README.md for details.
+#
+# Copyright 2018, OpenCensus Authors
+#
+# 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.
+
+load("//opencensus:copts.bzl", "DEFAULT_COPTS", "TEST_COPTS")
+
+licenses(["notice"])  # Apache 2.0
+
+package(default_visibility = ["//opencensus:__subpackages__"])
+
+cc_library(
+    name = "version",
+    hdrs = ["version.h"],
+    copts = DEFAULT_COPTS,
+)

opencensus/common/version.h

@@ -0,0 +1,22 @@
+// Copyright 2018, OpenCensus Authors
+//
+// 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.
+
+#ifndef OPENCENSUS_COMMON_VERSION_H_
+#define OPENCENSUS_COMMON_VERSION_H_
+
+// The current version of the opencensus core library. Macro to allow literal
+// string concatenation in constexpr statements.
+#define OPENCENSUS_VERSION "0.3.0-dev"
+
+#endif  // OPENCENSUS_COMMON_VERSION_H_

opencensus/exporters/trace/stackdriver/BUILD

@@ -29,6 +29,7 @@ cc_library(
     visibility = ["//visibility:public"],
     deps = [
         "//google/devtools/cloudtrace/v2:tracing_proto",
+        "//opencensus/common:version",
         "//opencensus/common/internal/grpc:status",
         "//opencensus/trace",
         "@com_github_grpc_grpc//:grpc++",

opencensus/exporters/trace/stackdriver/internal/stackdriver_exporter.cc

@@ -24,6 +24,7 @@
 #include "absl/time/clock.h"
 #include "google/devtools/cloudtrace/v2/tracing.grpc.pb.h"
 #include "opencensus/common/internal/grpc/status.h"
+#include "opencensus/common/version.h"
 #include "opencensus/trace/exporter/span_data.h"
 #include "opencensus/trace/exporter/span_exporter.h"
 
@@ -38,7 +39,7 @@ constexpr size_t kDisplayNameStringLen = 128;
 constexpr char kGoogleStackdriverTraceAddress[] = "cloudtrace.googleapis.com";
 
 constexpr char kAgentKey[] = "g.co/agent";
-constexpr char kAgentValue[] = "opencensus-cpp";
+constexpr char kAgentValue[] = "opencensus-cpp [" OPENCENSUS_VERSION "]";
 
 bool Validate(const google::protobuf::Timestamp& t) {
   const auto sec = t.seconds();