SERVER-59357 Initial scaffolding of the Fault class

7 files changed, 301 insertions, 19 deletions

diff --git a/src/mongo/db/process_health/SConscript b/src/mongo/db/process_health/SConscript
index f59342d05bf..4758adbd836 100644
--- a/src/mongo/db/process_health/SConscript
+++ b/src/mongo/db/process_health/SConscript
@@ -1,16 +1,17 @@
 # -*- mode: python -*-
 
-Import("env")
+Import('env')
 
 env = env.Clone()
 
 env.Library(
     target='fault_manager',
     source=[
-        "fault_manager.cpp",
+        'fault_impl.cpp',
+        'fault_manager.cpp',
     ],
     LIBDEPS=[
-        "$BUILD_DIR/mongo/base",
+        '$BUILD_DIR/mongo/base',
         '$BUILD_DIR/mongo/db/service_context',
     ],
     LIBDEPS_PRIVATE=[
@@ -18,11 +19,13 @@ env.Library(
 )
 
 env.CppUnitTest(
-    target="fault_manager_test",
+    target='fault_base_classes_test',
     source=[
-        "fault_manager_test.cpp",
+        'fault_impl_test.cpp',
+        'fault_manager_test.cpp',
     ],
     LIBDEPS=[
-        "fault_manager",
+        '$BUILD_DIR/mongo/util/clock_source_mock',
+        'fault_manager',
     ],
 )
diff --git a/src/mongo/db/process_health/fault.h b/src/mongo/db/process_health/fault.h
new file mode 100644
index 00000000000..6dbb2358772
--- /dev/null
+++ b/src/mongo/db/process_health/fault.h
@@ -0,0 +1,90 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+#pragma once
+
+#include <memory>
+
+#include "mongo/bson/bsonobjbuilder.h"
+#include "mongo/util/duration.h"
+#include "mongo/util/uuid.h"
+
+namespace mongo {
+namespace process_health {
+
+/**
+ * Detailed description of the current fault.
+ * @see FaultManager for more details.
+ */
+class Fault {
+    Fault(const Fault&) = delete;
+    Fault& operator=(const Fault&) = delete;
+
+public:
+    Fault() = default;
+    virtual ~Fault() = default;
+
+    virtual UUID getId() const = 0;
+
+    /**
+     * The fault severity value is an aggregate severity calculated
+     * from all facets currently owned by this instance.
+     *
+     * @return Current fault severity. The expected values:
+     *         0: Ok
+     *         (0, 1.0): Transient fault condition
+     *         [1.0, Inf): Active fault condition
+     */
+    virtual double getSeverity() const = 0;
+
+    /**
+     * Gets the duration of an active fault, if any.
+     * This is the time from the moment the severity reached the 1.0 value
+     * and stayed on or above 1.0.
+     *
+     * Note: each time the severity drops below 1.0 the duration is reset.
+     */
+    virtual Milliseconds getActiveFaultDuration() const = 0;
+
+    /**
+     * @return The lifetime of this fault from the moment it was created.
+     *         Invariant: getDuration() >= getActiveFaultDuration()
+     */
+    virtual Milliseconds getDuration() const = 0;
+
+    /**
+     * Describes the current fault.
+     */
+    virtual void appendDescription(BSONObjBuilder* builder) const = 0;
+};
+
+using FaultConstPtr = std::shared_ptr<const Fault>;
+
+
+}  // namespace process_health
+}  // namespace mongo
diff --git a/src/mongo/db/process_health/fault_impl.cpp b/src/mongo/db/process_health/fault_impl.cpp
new file mode 100644
index 00000000000..1a0a9db9f32
--- /dev/null
+++ b/src/mongo/db/process_health/fault_impl.cpp
@@ -0,0 +1,59 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/process_health/fault_impl.h"
+
+namespace mongo {
+namespace process_health {
+
+FaultImpl::FaultImpl(ServiceContext* svcCtx)
+    : _svcCtx(svcCtx), _startTime(_svcCtx->getFastClockSource()->now()) {
+    invariant(svcCtx);  // Will crash before this line, just for readability.
+}
+
+UUID FaultImpl::getId() const {
+    return _id;
+}
+
+double FaultImpl::getSeverity() const {
+    return 0;
+}
+
+Milliseconds FaultImpl::getActiveFaultDuration() const {
+    return Milliseconds(0);
+}
+
+Milliseconds FaultImpl::getDuration() const {
+    return Milliseconds(_svcCtx->getFastClockSource()->now() - _startTime);
+}
+
+void FaultImpl::appendDescription(BSONObjBuilder* builder) const {}
+
+}  // namespace process_health
+}  // namespace mongo
diff --git a/src/mongo/db/process_health/fault_impl.h b/src/mongo/db/process_health/fault_impl.h
new file mode 100644
index 00000000000..83deb49158a
--- /dev/null
+++ b/src/mongo/db/process_health/fault_impl.h
@@ -0,0 +1,70 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+#pragma once
+
+#include "mongo/db/process_health/fault.h"
+
+#include "mongo/db/service_context.h"
+#include "mongo/util/clock_source.h"
+#include "mongo/util/system_clock_source.h"
+#include "mongo/util/timer.h"
+
+namespace mongo {
+namespace process_health {
+
+/**
+ * Internal implementation of the Fault class.
+ * @see Fault
+ */
+class FaultImpl : public Fault {
+public:
+    explicit FaultImpl(ServiceContext* svcCtx);
+
+    ~FaultImpl() override = default;
+
+    // Fault interface.
+
+    UUID getId() const override;
+
+    double getSeverity() const override;
+
+    Milliseconds getActiveFaultDuration() const override;
+
+    Milliseconds getDuration() const override;
+
+    void appendDescription(BSONObjBuilder* builder) const override;
+
+private:
+    ServiceContext* const _svcCtx;
+    const UUID _id = UUID::gen();
+    const Date_t _startTime;
+};
+
+}  // namespace process_health
+}  // namespace mongo
diff --git a/src/mongo/db/process_health/fault_impl_test.cpp b/src/mongo/db/process_health/fault_impl_test.cpp
new file mode 100644
index 00000000000..e46cb5c4310
--- /dev/null
+++ b/src/mongo/db/process_health/fault_impl_test.cpp
@@ -0,0 +1,71 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/process_health/fault_impl.h"
+
+#include "mongo/unittest/unittest.h"
+#include "mongo/util/clock_source_mock.h"
+
+namespace mongo {
+namespace process_health {
+namespace {
+
+class FaultImplTest : public unittest::Test {
+public:
+    void setUp() override {
+        _svcCtx = ServiceContext::make();
+        _svcCtx->setFastClockSource(std::make_unique<ClockSourceMock>());
+        _faultImpl = std::make_unique<FaultImpl>(_svcCtx.get());
+    }
+
+    ClockSourceMock& clockSource() {
+        return *static_cast<ClockSourceMock*>(_svcCtx->getFastClockSource());
+    }
+
+    FaultImpl& fault() {
+        return *_faultImpl;
+    }
+
+private:
+    ServiceContext::UniqueServiceContext _svcCtx;
+
+    std::unique_ptr<FaultImpl> _faultImpl;
+};
+
+
+TEST_F(FaultImplTest, TimeSourceWorks) {
+    // Fault was just created, duration should be zero.
+    ASSERT_EQ(Milliseconds(0), fault().getDuration());
+    clockSource().advance(Milliseconds(1));
+    ASSERT_EQ(Milliseconds(1), fault().getDuration());
+}
+
+}  // namespace
+}  // namespace process_health
+}  // namespace mongo
diff --git a/src/mongo/db/process_health/fault_manager.cpp b/src/mongo/db/process_health/fault_manager.cpp
index 385721b8106..b7400c373e8 100644
--- a/src/mongo/db/process_health/fault_manager.cpp
+++ b/src/mongo/db/process_health/fault_manager.cpp
@@ -66,7 +66,7 @@ FaultState FaultManager::getFaultState() const {
     return FaultState::kOk;
 }
 
-boost::optional<FaultManager::FaultConstPtr> FaultManager::activeFault() const {
+boost::optional<FaultConstPtr> FaultManager::activeFault() const {
     return {};
 }
 
diff --git a/src/mongo/db/process_health/fault_manager.h b/src/mongo/db/process_health/fault_manager.h
index d886bf43917..ccdf8cf96eb 100644
--- a/src/mongo/db/process_health/fault_manager.h
+++ b/src/mongo/db/process_health/fault_manager.h
@@ -30,6 +30,7 @@
 
 #include <memory>
 
+#include "mongo/db/process_health/fault.h"
 #include "mongo/db/service_context.h"
 
 namespace mongo {
@@ -68,9 +69,6 @@ class FaultManager {
     FaultManager& operator=(const FaultManager&) = delete;
 
 public:
-    class Fault;
-    using FaultConstPtr = std::shared_ptr<const Fault>;
-
     FaultManager() = default;
     virtual ~FaultManager();
 
@@ -84,15 +82,6 @@ public:
     // Returns the current fault, if any.
     virtual boost::optional<FaultConstPtr> activeFault() const;
 
-    /**
-     * Detailed description of the current fault.
-     */
-    class Fault {
-    public:
-        Fault() = default;
-        virtual ~Fault() {}
-    };
-
 protected:
     // Starts the health check sequence and updates the internal state on completion.
     // This is invoked by the internal timer.