Make generic C++ decorator for handling SA_AIS_ERR_TRY_AGAIN return code
of AIS APIs.
---
src/base/Makefile.am | 5 +-
src/base/tests/try_again_decorator_test.cc | 48 +++++++++++++
src/base/try_again_decorator.h | 109 +++++++++++++++++++++++++++++
3 files changed, 161 insertions(+), 1 deletion(-)
create mode 100644 src/base/tests/try_again_decorator_test.cc
create mode 100644 src/base/try_again_decorator.h
diff --git a/src/base/Makefile.am b/src/base/Makefile.am
index 956cce6..f11b738 100644
--- a/src/base/Makefile.am
+++ b/src/base/Makefile.am
@@ -150,6 +150,7 @@ noinst_HEADERS += \
src/base/unix_client_socket.h \
src/base/unix_server_socket.h \
src/base/unix_socket.h \
+ src/base/try_again_decorator.h \
src/base/usrbuf.h
TESTS += bin/testleap bin/libbase_test bin/core_common_test
@@ -208,7 +209,9 @@ bin_libbase_test_SOURCES = \
src/base/tests/time_compare_test.cc \
src/base/tests/time_convert_test.cc \
src/base/tests/time_subtract_test.cc \
- src/base/tests/unix_socket_test.cc
+ src/base/tests/unix_socket_test.cc \
+ src/base/tests/try_again_decorator_test.cc
+
bin_libbase_test_LDADD = \
$(GTEST_DIR)/lib/libgtest.la \
diff --git a/src/base/tests/try_again_decorator_test.cc
b/src/base/tests/try_again_decorator_test.cc
new file mode 100644
index 0000000..ac8595d
--- /dev/null
+++ b/src/base/tests/try_again_decorator_test.cc
@@ -0,0 +1,48 @@
+/* -*- OpenSAF -*-
+ *
+ * (C) Copyright 2017 The OpenSAF Foundation
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. This file and program are licensed
+ * under the GNU Lesser General Public License Version 2.1, February 1999.
+ * The complete license can be accessed from the following location:
+ * http://opensource.org/licenses/lgpl-license.php
+ * See the Copying file included with the OpenSAF distribution for full
+ * licensing terms.
+ *
+ * Author(s): Ericsson AB
+ *
+ */
+
+#include "base/try_again_decorator.h"
+#include "gtest/gtest.h"
+
+static unsigned counter = 0;
+
+SaAisErrorT TestMethod() {
+ ++counter;
+ return SA_AIS_ERR_TRY_AGAIN;
+}
+
+TEST(TryAgainDecorator, DefaultRetryControl) {
+ // default interval = 40ms, timeout = 10 * 1000ms
+ using DefaultDecorator = base::TryAgainDecorator<>;
+ auto DecorTestMethod = DefaultDecorator::DecorateFunction(TestMethod);
+
+ DecorTestMethod();
+ EXPECT_GE(counter, 200);
+ EXPECT_LE(counter, 250);
+ counter = 0;
+}
+
+TEST(TryAgainDecorator, GivenRetryControl) {
+ // interval = 10ms, timeout = 1000ms
+ using TryAgainDecorator = base::TryAgainDecorator<10, 1 * 1000>;
+ auto DecorTestMethod = TryAgainDecorator::DecorateFunction(TestMethod);
+
+ DecorTestMethod();
+ EXPECT_GE(counter, 50);
+ EXPECT_LE(counter, 100);
+ counter = 0;
+}
diff --git a/src/base/try_again_decorator.h b/src/base/try_again_decorator.h
new file mode 100644
index 0000000..e676697
--- /dev/null
+++ b/src/base/try_again_decorator.h
@@ -0,0 +1,109 @@
+/* -*- OpenSAF -*-
+ *
+ * Copyright Ericsson AB 2017 - All Rights Reserved.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. This file and program are licensed
+ * under the GNU Lesser General Public License Version 2.1, February 1999.
+ * The complete license can be accessed from the following location:
+ * http://opensource.org/licenses/lgpl-license.php
+ * See the Copying file included with the OpenSAF distribution for full
+ * licensing terms.
+ *
+ */
+
+#ifndef BASE_TRY_AGAIN_DECORATOR_H_
+#define BASE_TRY_AGAIN_DECORATOR_H_
+
+#include <iostream>
+#include <functional>
+#include <saAis.h>
+#include "base/time.h"
+
+namespace base {
+
+//>
+// C++ decorator which escapsulates try again handling.
+//
+// E.g:
+// 1) If user wants to call saClmInitialize() which has try again
+// handling inside using this decorator, do this:
+//
+// using TryAgainDecorator = base::TryAgainDecorator<>;
+// auto saClmInitialize = TryAgainDecorator(::saClmInitialize);
+// if (saClmInitialize(handle, cbs, version) != SA_AIS_OK) {
+// // error handling
+// }
+//
+// 2) If user wants other retry control than default ones,
+// such as interval = 10ms, timeout = 10second, do this:
+//
+// using TryAgainDecorator = base::TryAgainDecorator<
+// {0, 10 * 1000 * 1000},
+// 10 * 1000
+// >
+// auto saClmInitialize = TryAgainDecorator(::saClmInitialize);
+// if (saClmInitialize(handle, cbs, version) != SA_AIS_OK) {
+// // error handling
+// }
+//
+//<
+
+// Default sleep time b/w retries {second, ns}
+static const timespec kInterval = {0, 40 * 1000 * 1000};
+// Default maximum time for retry loop (ms)
+static const uint64_t kTimeout = 10 * 1000;
+
+struct RetryControl {
+ RetryControl() : interval(kInterval), timeout(kTimeout) {}
+ RetryControl(timespec i, uint64_t t) : interval(i), timeout(t) {}
+ RetryControl(const RetryControl& ctrl)
+ : interval(ctrl.interval), timeout(ctrl.timeout) {}
+
+ // Sleep time b/w retries
+ timespec interval;
+ // Maximum time for retry loop
+ uint64_t timeout;
+};
+
+template <class> class Decorator;
+template <class T, class... Args>
+class Decorator<T(Args ...)> {
+ public:
+ explicit Decorator(const std::function<T(Args ...)>& f,
+ const RetryControl& ctrl)
+ : f_{f}, retry_ctrl_{ctrl} {}
+
+ explicit Decorator(const std::function<T(Args ...)>& f) : f_{f} {}
+
+ T operator()(Args ... args) {
+ T ais_error;
+ base::Timer wtime(retry_ctrl_.timeout);
+ while (wtime.is_timeout() == false) {
+ ais_error = f_(args...);
+ if (ais_error != SA_AIS_ERR_TRY_AGAIN) break;
+ base::Sleep(retry_ctrl_.interval);
+ }
+ return ais_error;
+ }
+
+ private:
+ const std::function<T(Args ...)> f_;
+ RetryControl retry_ctrl_;
+};
+
+template <uint64_t interval_ms = 40, uint64_t timeout_ms = 10 * 1000>
+class TryAgainDecorator {
+ public:
+ template<class T, class... Args>
+ static Decorator<T(Args...)> DecorateFunction(T (*f)(Args ...)) {
+ RetryControl ctrl({0, interval_ms * 1000 * 1000}, timeout_ms);
+ return Decorator<T(Args...)>
+ (std::function<T(Args...)>(f), ctrl);
+ }
+};
+
+} // namespace base
+
+#endif //< BASE_TRY_AGAIN_DECORATOR_H_
--
1.9.1
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Opensaf-devel mailing list
Opensaf-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/opensaf-devel
