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, 5 insertions, 4 deletions

diff --git a/src/mongo/s/version_manager.cpp b/src/mongo/s/version_manager.cpp
index 1496ebc1407..bc146e49074 100644
--- a/src/mongo/s/version_manager.cpp
+++ b/src/mongo/s/version_manager.cpp
@@ -222,10 +222,11 @@ namespace mongo {
                                     "version is zero" ) ) << endl;
         }
 
-        LOG(2) << " have to set shard version for conn: " << conn->getServerAddress() << " ns:" << ns
-               << " my last seq: " << sequenceNumber << "  current: " << officialSequenceNumber
-               << " version: " << version << " manager: " << manager.get()
-               << endl;
+        LOG(2).stream()
+            << " have to set shard version for conn: " << conn->getServerAddress() << " ns:" << ns
+            << " my last seq: " << sequenceNumber << "  current: " << officialSequenceNumber
+            << " version: " << version << " manager: " << manager.get()
+            << endl;
 
         const string versionableServerAddress(conn->getServerAddress());