Enhance the campaign test and document the behaviour when timeout is set (#205)

Signed-off-by: Tao He <sighingnow@gmail.com>

README.md

@@ -884,6 +884,10 @@ pplx::task<Response> resign(std::string const &name, int64_t lease_id,
                             std::string const &key, int64_t revision);
 ```
 
+Note that if grpc timeout is set, `campaign()` will return an timeout error response if it
+cannot acquire the election ownership within the timeout period. Otherwise will block until
+become the leader.
+
 The `Observer` returned by `observe()` can be use to monitor the changes of election ownership.
 The observer stream will be canceled when been destructed.
 

src/v3/AsyncElectionAction.cpp

@@ -31,12 +31,12 @@ etcdv3::AsyncCampaignResponse etcdv3::AsyncCampaignAction::ParseResponse()
 {
   AsyncCampaignResponse campaign_resp;
   campaign_resp.set_action(etcdv3::CAMPAIGN_ACTION);
-  
+
   if(!status.ok()) {
     campaign_resp.set_error_code(status.error_code());
     campaign_resp.set_error_message(status.error_message());
   }
-  else { 
+  else {
     campaign_resp.ParseResponse(reply);
   }
   return campaign_resp;

tst/CampaignTest.cpp

@@ -13,7 +13,7 @@
 static std::string etcd_uri = etcdv3::detail::resolve_etcd_endpoints(
 	"http://127.0.0.1:2379,http://127.0.0.1:2479,http://127.0.0.1:2579");
 
-TEST_CASE("campaign and loadership using keepalive") {
+TEST_CASE("campaign and leadership using keepalive") {
   etcd::Client etcd(etcd_uri);
   auto keepalive = etcd.leasekeepalive(5).get();
   auto lease_id = keepalive->Lease();
@@ -32,8 +32,73 @@ TEST_CASE("campaign and loadership using keepalive") {
   std::cout << "finish campaign" << std::endl;
 
   auto resp2 = etcd.leader("/leader").get();
-  std::cout << resp2.value().as_string() << std::endl;
+  CHECK(0 == resp2.error_code());
+  CHECK(value == resp2.value().as_string());
+  CHECK(resp1.value().key() == resp2.value().key());
   std::cout << resp2.value().key() << std::endl;
 
   std::cout << "finish leader" << std::endl;
+
+  auto resp3 = etcd.resign("/leader", resp1.value().lease(), resp1.value().key(), resp1.value().created_index()).get();
+  CHECK(0 == resp3.error_code());
+
+  std::cout << "finish resign" << std::endl;
+}
+
+
+TEST_CASE("concurrent campaign with grpc timeout") {
+  std::string value1 = std::string("192.168.1.6:1880");
+  std::string value2 = std::string("192.168.1.6:1890");
+
+  auto fn1 = [&]() {
+    etcd::Client etcd(etcd_uri);
+    auto keepalive = etcd.leasekeepalive(5).get();
+    auto lease_id = keepalive->Lease();
+    auto resp1 = etcd.campaign("/leader", lease_id, value1).get();
+    CHECK(0 == resp1.error_code());
+
+    std::this_thread::sleep_for(std::chrono::seconds(10));
+
+    // resign
+    auto resp2 = etcd.resign("/leader", resp1.value().lease(), resp1.value().key(), resp1.value().created_index()).get();
+    CHECK(0 == resp2.error_code());
+  };
+
+  auto fn2 = [&]() {
+    etcd::Client etcd(etcd_uri);
+    auto keepalive = etcd.leasekeepalive(5).get();
+    auto lease_id = keepalive->Lease();
+
+    // set client timeout
+    etcd.set_grpc_timeout(std::chrono::seconds(3));
+
+    std::this_thread::sleep_for(std::chrono::seconds(3));
+    auto resp1 = etcd.campaign("/leader", lease_id, value2).get();
+    std::cout <<resp1.error_code() << resp1.error_message() << std::endl;
+    CHECK(0 != resp1.error_code());
+
+    // wait until success
+    while (true) {
+      resp1 = etcd.campaign("/leader", lease_id, value2).get();
+      if (resp1.error_code() == 0) {
+        // check value
+        auto resp2 = etcd.leader("/leader").get();
+        CHECK(0 == resp2.error_code());
+        CHECK(value2 == resp2.value().as_string());
+        CHECK(resp1.value().key() == resp2.value().key());
+
+        // break the loop
+        break;
+      }
+    }
+
+    auto resp2 = etcd.resign("/leader", resp1.value().lease(), resp1.value().key(), resp1.value().created_index()).get();
+    CHECK(0 == resp2.error_code());
+  };
+
+  std::thread t1(fn1);
+  std::thread t2(fn2);
+
+  t1.join();
+  t2.join();
 }