Add GetPort(port) support to maintain compatibility with unittest TPortManager

Singleton did not allow reinitialisation, so in existing tests this line https://a.yandex-team.ru/arcadia/library/cpp/testing/common/ut/network_ut.cpp?rev=rXXXXXX#L45 did not have any effect. The tests worked just because in both tests the env var PORT_SYNC_PATH was the same and its changes did not affect the tests anyway.

As we need to change the env var NO_RANDOM_PORTS to run GetPort( port ) test, I had to make a reinitialisation method, which is now being called from inside the constructor, causing its double invocation during the tests. I could not find a better solution for Singleton(

3 files changed, 89 insertions, 8 deletions

diff --git a/library/cpp/testing/common/network.cpp b/library/cpp/testing/common/network.cpp
index 230c50ee6d..7a7ff2544c 100644
--- a/library/cpp/testing/common/network.cpp
+++ b/library/cpp/testing/common/network.cpp
@@ -96,27 +96,32 @@ namespace {
         static constexpr size_t Retries = 20;
     public:
         TPortManager()
-            : SyncDir_(GetEnv("PORT_SYNC_PATH"))
-            , Ranges_(GetPortRanges())
-            , TotalCount_(0)
         {
+            InitFromEnv();
+        }
+
+        void InitFromEnv() {
+            SyncDir_ = TFsPath(GetEnv("PORT_SYNC_PATH"));
             if (!SyncDir_.IsDefined()) {
-                SyncDir_ = TFsPath(GetSystemTempDir()) / "yandex_port_locks";
+                SyncDir_ = TFsPath(GetSystemTempDir()) / "testing_port_locks";
             }
             Y_VERIFY(SyncDir_.IsDefined());
             NFs::MakeDirectoryRecursive(SyncDir_);
 
+            Ranges_ = GetPortRanges();
+            TotalCount_ = 0;
             for (auto [left, right] : Ranges_) {
                 TotalCount_ += right - left;
             }
             Y_VERIFY(0 != TotalCount_);
+
+            DisableRandomPorts_ = !GetEnv("NO_RANDOM_PORTS").empty();
         }
 
         NTesting::TPortHolder GetFreePort() const {
             ui16 salt = RandomNumber<ui16>();
             for (ui16 attempt = 0; attempt < TotalCount_; ++attempt) {
                 ui16 probe = (salt + attempt) % TotalCount_;
-
                 for (auto [left, right] : Ranges_) {
                     if (probe >= right - left)
                         probe -= right - left;
@@ -165,6 +170,17 @@ namespace {
             Y_FAIL("Cannot get range of %zu ports!", count);
         }
 
+        NTesting::TPortHolder GetPort(ui16 port) const {
+            if (port && DisableRandomPorts_) {
+                auto ackport = TryAcquirePort(port);
+                if (ackport) {
+                    return NTesting::TPortHolder{std::move(ackport)};
+                }
+                Y_FAIL("Cannot acquire port %hu!", port);
+            }
+            return GetFreePort();
+        }
+
     private:
         THolder<NTesting::IPort> TryAcquirePort(ui16 port) const {
             auto lock = MakeHolder<TFileLock>(TString(SyncDir_ / ::ToString(port)));
@@ -178,7 +194,7 @@ namespace {
             TSockAddrInet6 addr("::", port);
             if (sock.Bind(&addr) != 0) {
                 lock->Release();
-                Y_VERIFY(EADDRINUSE == LastSystemError(), "unexpected error: %d", LastSystemError());
+                Y_VERIFY(EADDRINUSE == LastSystemError(), "unexpected error: %d, port: %d", LastSystemError(), port);
                 return nullptr;
             }
             return MakeHolder<TPortGuard>(port, std::move(lock));
@@ -188,15 +204,23 @@ namespace {
         TFsPath SyncDir_;
         TVector<std::pair<ui16, ui16>> Ranges_;
         size_t TotalCount_;
+        bool DisableRandomPorts_;
     };
 }
 
 namespace NTesting {
+    void InitPortManagerFromEnv() {
+        Singleton<TPortManager>()->InitFromEnv();
+    }
+
     TPortHolder GetFreePort() {
         return Singleton<TPortManager>()->GetFreePort();
     }
 
     namespace NLegacy {
+        TPortHolder GetPort( ui16 port ) {
+            return Singleton<TPortManager>()->GetPort(port);
+        }
         TVector<TPortHolder> GetFreePortsRange(size_t count) {
             return Singleton<TPortManager>()->GetFreePortsRange(count);
         }
diff --git a/library/cpp/testing/common/network.h b/library/cpp/testing/common/network.h
index eb4d32f3a1..4107145a7c 100644
--- a/library/cpp/testing/common/network.h
+++ b/library/cpp/testing/common/network.h
@@ -33,11 +33,16 @@ namespace NTesting {
     [[nodiscard]] TPortHolder GetFreePort();
 
     namespace NLegacy {
-        // Do not use this method, it needs only for TPortManager from unittests.
+        // Do not use these methods made for Unittest TPortManager backward compatibility.
         // Returns continuous sequence of the specified number of ports.
         [[nodiscard]] TVector<TPortHolder> GetFreePortsRange(size_t count);
+        //@brief Returns port from parameter if NO_RANDOM_PORTS env var is set, otherwise first free port
+        [[nodiscard]] TPortHolder GetPort(ui16 port);
     }
 
+    //@brief Reinitialize singleton from environment vars for tests
+    void InitPortManagerFromEnv();
+
     //@brief helper class for inheritance
     struct TFreePortOwner {
         TFreePortOwner() : Port_(GetFreePort()) {}
diff --git a/library/cpp/testing/common/ut/network_ut.cpp b/library/cpp/testing/common/ut/network_ut.cpp
index 6a40775fd9..2016e26b09 100644
--- a/library/cpp/testing/common/ut/network_ut.cpp
+++ b/library/cpp/testing/common/ut/network_ut.cpp
@@ -15,7 +15,7 @@ static TTempDir TmpDir;
 
 TEST(NetworkTest, FreePort) {
     NTesting::TScopedEnvironment envGuard("PORT_SYNC_PATH", TmpDir.Name());
-
+    NTesting::InitPortManagerFromEnv();
     TVector<NTesting::TPortHolder> ports(Reserve(100));
 
     for (size_t i = 0; i < 100; ++i) {
@@ -40,9 +40,61 @@ TEST(NetworkTest, FreePort) {
     }
 }
 
+TEST(NetworkTest, FreePortWithinRanges) {
+    NTesting::TScopedEnvironment envGuard{{
+            {"PORT_SYNC_PATH", TmpDir.Name()},
+            {"VALID_PORT_RANGE", "3456:7654"},
+        }};
+    NTesting::InitPortManagerFromEnv();
+
+    for (size_t i = 0; i < 100; ++i) {
+        auto holder = NTesting::GetFreePort();
+        ui16 port = holder;
+        ASSERT_GE(port, 3456u);
+        ASSERT_LE(port, 7654u);
+    }
+}
+
+TEST(NetworkTest, GetPortRandom) {
+    NTesting::TScopedEnvironment envGuard{{
+            {"PORT_SYNC_PATH", TmpDir.Name()},
+            {"NO_RANDOM_PORTS", ""},
+        }};
+    NTesting::InitPortManagerFromEnv();
+
+    ui16 testPort = 80; // value just must be outside the assignable range
+    for (size_t i = 0; i < 10; ++i) {
+        NTesting::TPortHolder assigned = NTesting::NLegacy::GetPort(testPort);
+        ui16 assignedInt = assigned;
+        ASSERT_NE(testPort, assignedInt);
+    }
+}
+
+TEST(NetworkTest, GetPortNonRandom) {
+    NTesting::TScopedEnvironment envGuard{{
+            {"PORT_SYNC_PATH", TmpDir.Name()},
+            {"NO_RANDOM_PORTS", "1"},
+        }};
+    NTesting::InitPortManagerFromEnv();
+
+    TVector<ui16> ports(Reserve(100)); // keep integers, we don't need the ports to remain allocated
+
+    for (size_t i = 0; i < 10; ++i) {
+        auto portHolder = NTesting::GetFreePort();
+        ports.push_back(portHolder);
+    }
+
+    for (auto& testPort : ports) {
+        NTesting::TPortHolder assigned = NTesting::NLegacy::GetPort(testPort);
+        ui16 assignedInt = assigned;
+        ASSERT_EQ(testPort, assignedInt);
+    }
+}
+
 
 TEST(FreePortTest, FreePortsRange) {
     NTesting::TScopedEnvironment envGuard("PORT_SYNC_PATH", TmpDir.Name());
+    NTesting::InitPortManagerFromEnv();
 
     for (ui16 i = 2; i < 10; ++i) {
         TVector<NTesting::TPortHolder> ports = NTesting::NLegacy::GetFreePortsRange(i);