Redo #817. Update pubsub example channel creation and credentials

build.json

@@ -1757,7 +1757,6 @@
       ],
       "deps": [
         "pubsub_client_lib",
-        "grpc++_test_util",
         "grpc_test_util",
         "grpc++",
         "grpc",

examples/pubsub/main.cc

@@ -41,6 +41,7 @@
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
 #include <gflags/gflags.h>
+#include <grpc++/channel_arguments.h>
 #include <grpc++/channel_interface.h>
 #include <grpc++/create_channel.h>
 #include <grpc++/credentials.h>
@@ -48,17 +49,11 @@
 
 #include "examples/pubsub/publisher.h"
 #include "examples/pubsub/subscriber.h"
-#include "test/cpp/util/create_test_channel.h"
 
 DEFINE_int32(server_port, 443, "Server port.");
 DEFINE_string(server_host,
               "pubsub-staging.googleapis.com", "Server host to connect to");
 DEFINE_string(project_id, "", "GCE project id such as stoked-keyword-656");
-DEFINE_string(service_account_key_file, "",
-              "Path to service account json key file.");
-DEFINE_string(oauth_scope,
-              "https://www.googleapis.com/auth/cloud-platform",
-              "Scope for OAuth tokens.");
 
 // In some distros, gflags is in the namespace google, and in some others,
 // in gflags. This hack is enabling us to find both.
@@ -75,17 +70,6 @@ const char kMessageData[] = "Test Data";
 
 }  // namespace
 
-grpc::string GetServiceAccountJsonKey() {
-  grpc::string json_key;
-  if (json_key.empty()) {
-    std::ifstream json_key_file(FLAGS_service_account_key_file);
-    std::stringstream key_stream;
-    key_stream << json_key_file.rdbuf();
-    json_key = key_stream.str();
-  }
-  return json_key;
-}
-
 int main(int argc, char** argv) {
   grpc_init();
   ParseCommandLineFlags(&argc, &argv, true);
@@ -93,23 +77,12 @@ int main(int argc, char** argv) {
 
   std::ostringstream ss;
 
-  std::unique_ptr<grpc::Credentials> creds;
-  if (FLAGS_service_account_key_file != "") {
-    grpc::string json_key = GetServiceAccountJsonKey();
-    creds = grpc::CredentialsFactory::ServiceAccountCredentials(
-        json_key, FLAGS_oauth_scope, std::chrono::hours(1));
-  } else {
-    creds = grpc::CredentialsFactory::ComputeEngineCredentials();
-  }
-
   ss << FLAGS_server_host << ":" << FLAGS_server_port;
-  std::shared_ptr<grpc::ChannelInterface> channel(
-      grpc::CreateTestChannel(
-          ss.str(),
-          FLAGS_server_host,
-          true,                // enable SSL
-          true,                // use prod roots
-          creds));
+
+  std::unique_ptr<grpc::Credentials> creds =
+      grpc::CredentialsFactory::GoogleDefaultCredentials();
+  std::shared_ptr<grpc::ChannelInterface> channel =
+      grpc::CreateChannel(ss.str(), creds, grpc::ChannelArguments());
 
   grpc::examples::pubsub::Publisher publisher(channel);
   grpc::examples::pubsub::Subscriber subscriber(channel);
@@ -127,8 +100,9 @@ int main(int argc, char** argv) {
   grpc::string subscription_topic;
   if (subscriber.GetSubscription(
       subscription_name, &subscription_topic).IsOk()) {
-    subscriber.DeleteSubscription(subscription_name);
+    s = subscriber.DeleteSubscription(subscription_name);
   }
+
   if (publisher.GetTopic(topic).IsOk()) publisher.DeleteTopic(topic);
 
   grpc::Status s = publisher.CreateTopic(topic);