WithRetry: Replace template parameters by std::function

Now also requires guarding for bootstrapping to not bring in grpc.

3 files changed, 137 insertions, 114 deletions

diff --git a/src/buildtool/common/remote/TARGETS b/src/buildtool/common/remote/TARGETS
index 52e3f91a..cdf4c72a 100644
--- a/src/buildtool/common/remote/TARGETS
+++ b/src/buildtool/common/remote/TARGETS
@@ -52,12 +52,9 @@
   { "type": ["@", "rules", "CC", "library"]
   , "name": ["retry"]
   , "hdrs": ["retry.hpp"]
-  , "deps":
-    [ ["src/buildtool/logging", "log_level"]
-    , ["src/buildtool/logging", "logging"]
-    , ["@", "grpc", "", "grpc++"]
-    , "retry_config"
-    ]
+  , "srcs": ["retry.cpp"]
+  , "deps": [["@", "grpc", "", "grpc++"], ["src/buildtool/logging", "logging"]]
   , "stage": ["src", "buildtool", "common", "remote"]
+  , "private-deps": ["retry_config", ["src/buildtool/logging", "log_level"]]
   }
 }
diff --git a/src/buildtool/common/remote/retry.cpp b/src/buildtool/common/remote/retry.cpp
new file mode 100644
index 00000000..5d75585c
--- /dev/null
+++ b/src/buildtool/common/remote/retry.cpp
@@ -0,0 +1,112 @@
+// Copyright 2024 Huawei Cloud Computing Technology Co., Ltd.
+//
+// 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.
+
+#include "src/buildtool/common/remote/retry.hpp"
+#ifndef BOOTSTRAP_BUILD_TOOL
+
+#include <chrono>
+#include <thread>
+
+#include "src/buildtool/common/remote/retry_config.hpp"
+#include "src/buildtool/logging/log_level.hpp"
+
+auto WithRetry(CallableReturningRetryResponse const& f,
+               Logger const& logger) noexcept -> bool {
+    try {
+        auto const& attempts = RetryConfig::GetMaxAttempts();
+        for (auto attempt = 1U; attempt <= attempts; ++attempt) {
+            auto [ok, fatal, error_msg] = f();
+            if (ok) {
+                return true;
+            }
+            if (fatal) {
+                if (error_msg) {
+                    logger.Emit(LogLevel::Error, "{}", *error_msg);
+                }
+                return false;
+            }
+            // don't wait if it was the last attempt
+            if (attempt < attempts) {
+                auto const sleep_for_seconds =
+                    RetryConfig::GetSleepTimeSeconds(attempt);
+                logger.Emit(kRetryLogLevel,
+                            "Attempt {}/{} failed{} Retrying in {} seconds.",
+                            attempt,
+                            attempts,
+                            error_msg ? fmt::format(": {}", *error_msg) : ".",
+                            sleep_for_seconds);
+                std::this_thread::sleep_for(
+                    std::chrono::seconds(sleep_for_seconds));
+            }
+            else {
+                if (error_msg) {
+                    logger.Emit(LogLevel::Error,
+                                "After {} attempts: {}",
+                                attempt,
+                                *error_msg);
+                }
+            }
+        }
+    } catch (...) {
+        logger.Emit(LogLevel::Error, "WithRetry: caught unknown exception");
+    }
+    return false;
+}
+auto WithRetry(CallableReturningGrpcStatus const& f,
+               Logger const& logger) noexcept -> std::pair<bool, grpc::Status> {
+    grpc::Status status{};
+    try {
+        auto attempts = RetryConfig::GetMaxAttempts();
+        for (auto attempt = 1U; attempt <= attempts; ++attempt) {
+            status = f();
+            if (status.ok() or
+                status.error_code() != grpc::StatusCode::UNAVAILABLE) {
+                return {status.ok(), std::move(status)};
+            }
+            // don't wait if it was the last attempt
+            if (attempt < attempts) {
+                auto const sleep_for_seconds =
+                    RetryConfig::GetSleepTimeSeconds(attempt);
+                logger.Emit(
+                    kRetryLogLevel,
+                    "Attempt {}/{} failed: {}: {}: Retrying in {} seconds.",
+                    attempt,
+                    attempts,
+                    static_cast<int>(status.error_code()),
+                    status.error_message(),
+                    sleep_for_seconds);
+                std::this_thread::sleep_for(
+                    std::chrono::seconds(sleep_for_seconds));
+            }
+            else {
+                // The caller performs a second check on the
+                // status.error_code(), and, eventually, emits to Error level
+                // there.
+                //
+                // To avoid duplication of similar errors, we emit to Debug
+                // level.
+                logger.Emit(LogLevel::Debug,
+                            "After {} attempts: {}: {}",
+                            attempt,
+                            static_cast<int>(status.error_code()),
+                            status.error_message());
+            }
+        }
+    } catch (...) {
+        logger.Emit(LogLevel::Error, "WithRetry: caught unknown exception");
+    }
+    return {false, std::move(status)};
+}
+
+#endif  // BOOTSTRAP_BUILD_TOOL
diff --git a/src/buildtool/common/remote/retry.hpp b/src/buildtool/common/remote/retry.hpp
index 6e164af1..c0ce318b 100644
--- a/src/buildtool/common/remote/retry.hpp
+++ b/src/buildtool/common/remote/retry.hpp
@@ -15,13 +15,14 @@
 #ifndef INCLUDED_SRC_BUILDTOOL_COMMON_RETRY_HPP
 #define INCLUDED_SRC_BUILDTOOL_COMMON_RETRY_HPP
 
+#ifndef BOOTSTRAP_BUILD_TOOL
+
+#include <functional>
 #include <optional>
-#include <thread>
-#include <utility>  // std::move
+#include <string>
+#include <utility>
 
 #include "grpcpp/grpcpp.h"
-#include "src/buildtool/common/remote/retry_config.hpp"
-#include "src/buildtool/logging/log_level.hpp"
 #include "src/buildtool/logging/logger.hpp"
 
 // Utility class to help detecting when exit the retry loop. This class can be
@@ -36,117 +37,30 @@
 // caller.
 struct RetryResponse {
     // When set to true, it means the function successfully run
-    bool ok{false};
+    bool ok = false;
     // When set to true, it means that it is not worthy to retry.
-    bool exit_retry_loop{false};
+    bool exit_retry_loop = false;
     // error message logged when exit_retry_loop was set to true or when the
     // last retry attempt failed
-    std::optional<std::string> error_msg{std::nullopt};
+    std::optional<std::string> error_msg = std::nullopt;
 };
 
-template <typename F>
-concept CallableReturningRetryResponse = requires(F const& f) {
-    {RetryResponse{f()}};
-};
+using CallableReturningRetryResponse = std::function<RetryResponse(void)>;
 
-template <CallableReturningRetryResponse F>
-// \p f is the callable invoked with a back off algorithm. The retry loop is
-// interrupted when one of the two member of the returned RetryResponse object
-// is set to true.
-[[nodiscard]] auto WithRetry(F const& f, Logger const& logger) noexcept
-    -> bool {
-    try {
-        auto const& attempts = RetryConfig::GetMaxAttempts();
-        for (auto attempt = 1U; attempt <= attempts; ++attempt) {
-            auto [ok, fatal, error_msg] = f();
-            if (ok) {
-                return true;
-            }
-            if (fatal) {
-                if (error_msg) {
-                    logger.Emit(LogLevel::Error, "{}", *error_msg);
-                }
-                return false;
-            }
-            // don't wait if it was the last attempt
-            if (attempt < attempts) {
-                auto const sleep_for_seconds =
-                    RetryConfig::GetSleepTimeSeconds(attempt);
-                logger.Emit(kRetryLogLevel,
-                            "Attempt {}/{} failed{} Retrying in {} seconds.",
-                            attempt,
-                            attempts,
-                            error_msg ? fmt::format(": {}", *error_msg) : ".",
-                            sleep_for_seconds);
-                std::this_thread::sleep_for(
-                    std::chrono::seconds(sleep_for_seconds));
-            }
-            else {
-                if (error_msg) {
-                    logger.Emit(LogLevel::Error,
-                                "After {} attempts: {}",
-                                attempt,
-                                *error_msg);
-                }
-            }
-        }
-    } catch (...) {
-        logger.Emit(LogLevel::Error, "WithRetry: caught unknown exception");
-    }
-    return false;
-}
+/// \brief Calls a function with a retry strategy using a backoff algorithm.
+/// Retry loop interrupts when one of the two members of the function's returned
+/// RetryResponse object is set to true.
+[[nodiscard]] auto WithRetry(CallableReturningRetryResponse const& f,
+                             Logger const& logger) noexcept -> bool;
 
-template <typename F>
-concept CallableReturningGrpcStatus = requires(F const& f) {
-    {grpc::Status{f()}};
-};
+using CallableReturningGrpcStatus = std::function<grpc::Status(void)>;
 
-template <CallableReturningGrpcStatus F>
-// F is the function to be invoked with a back off algorithm
-[[nodiscard]] auto WithRetry(F const& f, Logger const& logger) noexcept
-    -> std::pair<bool, grpc::Status> {
-    grpc::Status status{};
-    try {
-        auto attempts = RetryConfig::GetMaxAttempts();
-        for (auto attempt = 1U; attempt <= attempts; ++attempt) {
-            status = f();
-            if (status.ok() or
-                status.error_code() != grpc::StatusCode::UNAVAILABLE) {
-                return {status.ok(), std::move(status)};
-            }
-            // don't wait if it was the last attempt
-            if (attempt < attempts) {
-                auto const sleep_for_seconds =
-                    RetryConfig::GetSleepTimeSeconds(attempt);
-                logger.Emit(
-                    kRetryLogLevel,
-                    "Attempt {}/{} failed: {}: {}: Retrying in {} seconds.",
-                    attempt,
-                    attempts,
-                    static_cast<int>(status.error_code()),
-                    status.error_message(),
-                    sleep_for_seconds);
-                std::this_thread::sleep_for(
-                    std::chrono::seconds(sleep_for_seconds));
-            }
-            else {
-                // The caller performs a second check on the
-                // status.error_code(), and, eventually, emits to Error level
-                // there.
-                //
-                // To avoid duplication of similar errors, we emit to Debug
-                // level.
-                logger.Emit(LogLevel::Debug,
-                            "After {} attempts: {}: {}",
-                            attempt,
-                            static_cast<int>(status.error_code()),
-                            status.error_message());
-            }
-        }
-    } catch (...) {
-        logger.Emit(LogLevel::Error, "WithRetry: caught unknown exception");
-    }
-    return {false, std::move(status)};
-}
+/// \brief Calls a function with a retry strategy using a backoff algorithm.
+/// Retry loop interrupts when function returns an error code different from
+/// UNAVAILABLE.
+[[nodiscard]] auto WithRetry(CallableReturningGrpcStatus const& f,
+                             Logger const& logger) noexcept
+    -> std::pair<bool, grpc::Status>;
 
+#endif  // BOOTSTRAP_BUILD_TOOL
 #endif  // INCLUDED_SRC_BUILDTOOL_COMMON_RETRY_HPP