SERVER-41686 Add unittest to prototype structured logging using boost::log.

* JSON and Text formatting, including with custom types
* Google benchmark to compare against current log system
* Ramlog, Console and File logging prototyped
* Two ways to implement multiple log domains

1 files changed, 121 insertions, 0 deletions

diff --git a/src/mongo/logv2/log_component_settings.cpp b/src/mongo/logv2/log_component_settings.cpp
new file mode 100644
index 00000000000..603cfd6729f
--- /dev/null
+++ b/src/mongo/logv2/log_component_settings.cpp
@@ -0,0 +1,121 @@
+/**
+ *    Copyright (C) 2018-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/platform/basic.h"
+
+#include "mongo/logv2/log_component_settings.h"
+
+#include "mongo/util/assert_util.h"
+
+namespace mongo {
+namespace logv2 {
+
+LogComponentSettings::LogComponentSettings() {
+    _minimumLoggedSeverity[LogComponent::kDefault].store(LogSeverity::Log().toInt());
+
+    for (int i = 0; i < int(LogComponent::kNumLogComponents); ++i) {
+        _minimumLoggedSeverity[i].store(_minimumLoggedSeverity[LogComponent::kDefault].load());
+        _hasMinimumLoggedSeverity[i].store(false);
+    }
+
+    _hasMinimumLoggedSeverity[LogComponent::kDefault].store(true);
+}
+
+LogComponentSettings::~LogComponentSettings() {}
+
+bool LogComponentSettings::hasMinimumLogSeverity(LogComponent component) const {
+    dassert(int(component) >= 0 && int(component) < LogComponent::kNumLogComponents);
+    return _hasMinimumLoggedSeverity[component].load();
+}
+
+LogSeverity LogComponentSettings::getMinimumLogSeverity(LogComponent component) const {
+    dassert(int(component) >= 0 && int(component) < LogComponent::kNumLogComponents);
+    return LogSeverity::cast(_minimumLoggedSeverity[component].load());
+}
+
+void LogComponentSettings::setMinimumLoggedSeverity(LogComponent component, LogSeverity severity) {
+    dassert(int(component) >= 0 && int(component) < LogComponent::kNumLogComponents);
+    stdx::lock_guard<stdx::mutex> lk(_mtx);
+    _setMinimumLoggedSeverityInLock(component, severity);
+}
+
+void LogComponentSettings::_setMinimumLoggedSeverityInLock(LogComponent component,
+                                                           LogSeverity severity) {
+    _minimumLoggedSeverity[component].store(severity.toInt());
+    _hasMinimumLoggedSeverity[component].store(true);
+
+    // Every unconfigured component will inherit log severity from parent.
+    // Traversing the severity array once works because child components always
+    // come after the parent in the LogComponent::Value enumeration.
+    for (int i = 0; i < int(LogComponent::kNumLogComponents); ++i) {
+        if (!_hasMinimumLoggedSeverity[i].load()) {
+            LogComponent::Value v = LogComponent::Value(i);
+            LogComponent parentComponent = LogComponent(v).parent();
+            LogSeverity parentSeverity = getMinimumLogSeverity(parentComponent);
+            _minimumLoggedSeverity[i].store(parentSeverity.toInt());
+        }
+    }
+
+    if (kDebugBuild) {
+        // This loop validates the guarantee that either an element has an individual log severity
+        // set or that it's value is equal to its parent's (i.e. either the value is set or
+        // inherited).
+        for (int i = 0; i < int(LogComponent::kNumLogComponents); ++i) {
+            LogComponent::Value v = LogComponent::Value(i);
+            LogComponent parentComponent = LogComponent(v).parent();
+            invariant(_hasMinimumLoggedSeverity[i].load() ||
+                      _minimumLoggedSeverity[i].load() ==
+                          _minimumLoggedSeverity[parentComponent].load());
+        }
+    }
+}
+
+void LogComponentSettings::clearMinimumLoggedSeverity(LogComponent component) {
+    dassert(int(component) >= 0 && int(component) < LogComponent::kNumLogComponents);
+
+    stdx::lock_guard<stdx::mutex> lk(_mtx);
+
+    // LogComponent::kDefault must always be configured.
+    if (component == LogComponent::kDefault) {
+        _setMinimumLoggedSeverityInLock(component, LogSeverity::Log());
+        return;
+    }
+
+    // Set unconfigured severity level to match LogComponent::kDefault.
+    _setMinimumLoggedSeverityInLock(component, getMinimumLogSeverity(component.parent()));
+    _hasMinimumLoggedSeverity[component].store(false);
+}
+
+bool LogComponentSettings::shouldLog(LogComponent component, LogSeverity severity) const {
+    dassert(int(component) >= 0 && int(component) < LogComponent::kNumLogComponents);
+    return severity >= LogSeverity::cast(_minimumLoggedSeverity[component].loadRelaxed());
+}
+
+}  // logv2
+}  // mongo