Extract gethostname into a dedicated module. Add unit test and better…

… error management.

src/engine/src/coincentercommands.cpp

@@ -4,12 +4,12 @@
 #include <filesystem>
 #include <iostream>
 #include <span>
+#include <string_view>
 #include <utility>
 
 #include "cct_invalid_argument_exception.hpp"
-#include "cct_log.hpp"
-#include "cct_string.hpp"
 #include "cct_vector.hpp"
+#include "coincentercommand.hpp"
 #include "coincentercommandtype.hpp"
 #include "coincenteroptions.hpp"
 #include "commandlineoptionsparser.hpp"
@@ -19,6 +19,7 @@
 #include "monetaryamount.hpp"
 #include "ordersconstraints.hpp"
 #include "priceoptions.hpp"
+#include "priceoptionsdef.hpp"
 #include "stringoptionparser.hpp"
 #include "timedef.hpp"
 #include "tradedefinitions.hpp"

src/monitoring/src/prometheusmetricgateway.cpp

@@ -7,6 +7,7 @@
 
 #include <cassert>
 #include <chrono>
+#include <exception>
 #include <map>
 #include <memory>
 #include <mutex>
@@ -18,39 +19,27 @@
 #include "abstractmetricgateway.hpp"
 #include "cct_exception.hpp"
 #include "cct_log.hpp"
+#include "gethostname.hpp"
 #include "metric.hpp"
 #include "monitoringinfo.hpp"
 #include "timedef.hpp"
 
-#ifdef CCT_MSVC
-#include <Winsock2.h>
-#else
-#include <unistd.h>
-#endif
-
 namespace cct {
 
 namespace {
-constexpr int kHTTPSuccessReturnCode = 200;
+constexpr auto kHTTPSuccessReturnCode = 200;
 
 // Constants to control frequency of flushes to Prometheus instance
-constexpr Duration kPrometheusAutoFlushPeriod = std::chrono::minutes(3);
-constexpr int kCheckFlushCounter = 20;
-
-std::string GetHostName() {
-  char hostname[1024];
-  if (::gethostname(hostname, sizeof(hostname)) != 0) {
-    hostname[0] = '\0';
-  }
-  return hostname;
-}
+constexpr auto kPrometheusAutoFlushPeriod = std::chrono::minutes(3);
+constexpr auto kCheckFlushCounter = 20;
 
 }  // namespace
 
 PrometheusMetricGateway::PrometheusMetricGateway(const MonitoringInfo& monitoringInfo)
     : AbstractMetricGateway(monitoringInfo),
       _gateway(std::string(monitoringInfo.address()), std::to_string(monitoringInfo.port()),
-               std::string(monitoringInfo.jobName()), prometheus::Gateway::GetInstanceLabel(GetHostName()),
+               std::string(monitoringInfo.jobName()),
+               prometheus::Gateway::GetInstanceLabel(GetHostName().toStdString()),
                std::string(monitoringInfo.username()), std::string(monitoringInfo.password())),
       _registry(std::make_shared<Registry>()),
       _lastFlushedTime(Clock::now()),
@@ -63,7 +52,7 @@ PrometheusMetricGateway::~PrometheusMetricGateway() {
   // We should not throw in a destructor - catch any exception and do nothing, not even a log (it could throw)
   try {
     flush();
-  } catch (...) {
+  } catch (const std::exception&) {
   }
 }
 

src/objects/include/logginginfo.hpp

@@ -16,7 +16,7 @@ namespace cct {
 /// @brief Encapsulates loggers lifetime and set-up.
 class LoggingInfo {
  public:
-  static constexpr int64_t kDefaultFileSizeInBytes = 5 * 1024 * 1024;
+  static constexpr int64_t kDefaultFileSizeInBytes = 5L * 1024 * 1024;
   static constexpr int32_t kDefaultNbMaxFiles = 10;
   static constexpr char const *const kOutputLoggerName = "output";
 

src/tech/CMakeLists.txt

@@ -62,6 +62,18 @@ add_unit_test(
     nlohmann_json::nlohmann_json
 )
 
+add_unit_test(
+    gethostname_test
+    src/gethostname.cpp
+    test/gethostname_test.cpp
+    DEFINITIONS
+    CCT_DISABLE_SPDLOG
+)
+
+if(WIN32)
+  target_link_libraries(gethostname_test wsock32 ws2_32)
+endif()
+
 add_unit_test(
     mathhelpers_test
     test/mathhelpers_test.cpp

src/tech/include/gethostname.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "cct_string.hpp"
+
+namespace cct {
+/// Safe version of gethostname, working in POSIX and Windows with similar behavior.
+string GetHostName();
+}  // namespace cct

src/tech/src/gethostname.cpp

@@ -0,0 +1,57 @@
+#include "gethostname.hpp"
+
+#include "cct_config.hpp"
+#include "cct_exception.hpp"
+#include "cct_string.hpp"
+#ifdef CCT_MSVC
+#include <Winsock2.h>
+#else
+#include <errno.h>
+#include <unistd.h>
+#endif
+
+namespace cct {
+/// Safe version of gethostname, working in POSIX and Windows with similar behavior.
+string GetHostName() {
+  string hostname(16U, '\0');
+  static constexpr std::size_t kMaxHostNameSize = 1024;
+  std::size_t nullTerminatedCharPos = 0;
+  do {
+    auto errorCode = ::gethostname(hostname.data(), hostname.size() - 1U);
+    if (errorCode != 0) {
+#ifdef CCT_MSVC
+      // In Windows, too small buffer returns an error WSAEFAULT
+      if (errorCode == WSAEFAULT) {
+#else
+      // In Posix, too small buffer returns an error ENAMETOOLONG set in errno
+      if (errno == ENAMETOOLONG) {
+#endif
+        nullTerminatedCharPos = hostname.size() - 1U;
+        hostname.resize(2 * hostname.size(), '\0');
+        continue;
+      }
+      throw exception("Error {} in gethostname", errorCode);
+    }
+#ifndef CCT_MSVC
+    if (hostname.back() != '\0') {
+      // In POSIX, if the null-terminated hostname is too large to fit, then the name is truncated, and no error is
+      // returned, meaning that last char has necessarily been written to
+      nullTerminatedCharPos = hostname.size() - 1U;
+      hostname.resize(2 * hostname.size(), '\0');
+      continue;
+    }
+#endif
+    if (hostname.size() > kMaxHostNameSize) {
+      throw exception("Unexpected host name size length {}", hostname.size());
+    }
+    break;
+  } while (true);
+
+  auto hostnameSize = hostname.find('\0', nullTerminatedCharPos);
+  if (hostnameSize == string::npos) {
+    throw exception("Unexpected error in GetHostName algorithm");
+  }
+  hostname.resize(hostnameSize);
+  return hostname;
+}
+}  // namespace cct

src/tech/test/gethostname_test.cpp

@@ -0,0 +1,12 @@
+#include "gethostname.hpp"
+
+#include <gtest/gtest.h>
+
+namespace cct {
+TEST(GetHostNameTest, Default) {
+  auto currentHostName = GetHostName();
+
+  EXPECT_FALSE(currentHostName.empty());
+  EXPECT_EQ(currentHostName.find('\0'), string::npos);
+}
+}  // namespace cct