SERVER-10084 New logging implementation.

This change-set:

* Introduces a new top-level directory, mongo/logger, containing most of the implementation of logging functionality formerly found in log.cpp/log.h.

* Cleans up existing, unusual uses of the logging system that were not trivially compatible with the new implementation.

* Replaces Logstream/Nulstream with a LogstreamBuilder object, whose destructor writes log messages.  This new LogstreamBuilder is reentrant, unlike the old logging code, which was thread-safe but not reentrant.  Additionally, std::endl is no longer required to terminate a log line.  When a LogstreamBuilder goes out of scope, the log message gets committed.

* Separates the log system into several components: a global LogManager, several LogDomains, various kinds of Appenders (e.g., SyslogAppender) and Encoders (for formatting messages).

* Allows unit tests to capture and examine log output.

This patch does _not_ introduce support for hierarchical log domains, or for enabling and disabling specific log domains when the server is running in a multi-threaded mode.  This is future work.

1 files changed, 53 insertions, 0 deletions

diff --git a/src/mongo/logger/message_event_utf8_encoder.h b/src/mongo/logger/message_event_utf8_encoder.h
new file mode 100644
index 00000000000..948f39508bd
--- /dev/null
+++ b/src/mongo/logger/message_event_utf8_encoder.h
@@ -0,0 +1,53 @@
+/*    Copyright 2013 10gen Inc.
+ *
+ *    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.
+ */
+
+#pragma once
+
+#include "mongo/logger/encoder.h"
+#include "mongo/logger/message_event.h"
+
+namespace mongo {
+namespace logger {
+
+    /**
+     * Encoder that writes log messages of the style that MongoDB writes to console and files.
+     */
+    class MessageEventDetailsEncoder : public Encoder<MessageEventEphemeral> {
+    public:
+        virtual ~MessageEventDetailsEncoder();
+        virtual std::ostream& encode(const MessageEventEphemeral& event, std::ostream& os);
+    };
+
+    /**
+     * Encoder that generates log messages suitable for syslog.
+     */
+    class MessageEventWithContextEncoder : public Encoder<MessageEventEphemeral> {
+    public:
+        virtual ~MessageEventWithContextEncoder();
+        virtual std::ostream& encode(const MessageEventEphemeral& event, std::ostream& os);
+    };
+
+
+    /**
+     * Encoder that generates log messages containing only the raw text of the message.
+     */
+    class MessageEventUnadornedEncoder : public Encoder<MessageEventEphemeral> {
+    public:
+        virtual ~MessageEventUnadornedEncoder();
+        virtual std::ostream& encode(const MessageEventEphemeral& event, std::ostream& os);
+    };
+
+}  // namespace logger
+}  // namespace mongo