source: fact/Evidence/readme.txt@ 15063

Version history
---------------

19/5/2010       Service histories now available via DimRpc from DColl, not via .hist service
                        When regular expression compiling results in error, State is set to ERROR, not
                        FATAL. The erroneous expression is ignored in the following.
25/5/2010       Service history remains available if service itself become unavailable. If not
                        yet in memory, reading from file is tried. Improved error handling of
                        history files.
28/5/2010       Changed name of 'State' service to 'Message' to better reflect its functionality.
                        Added client information to log file entries.                   
30/5/2010       Created Bridge server that repeats services from one DNS to another.
                        Service quality now also written to slow data file.
31/5/2010       Configuration file format follows semi-standard INI format.
7/6/2010        Separated History service from DColl. History format changed, now includes
                        service format (allows history access also when service is unavailable).
11/6/2010       Bridge does not forward history service
17/6/2010       Added SendToLog() method. Changed severity encoding of Message service to
                        use standard DIM structure of format "I:1;C"
18/6/2010       Alarm server configuration accepts now one email address per server. A new
                        service for each observed server SERVERNAME/AlarmLevel contains the highest
                        level that occurred in the past. Reset of alarm level only via a DIM command.
19/6/2010       ToString() now returns std::string
23/6/2010       GetConfig() returns std::string. Non-blocking configuration request in case
                        GetConfig() not called from main thread. Access to configuration information
                        internally mutex protected.
24/6/2010       Workaround for erroneous /SERVICE_LIST updates. Added static tokenize method to
                        Evidence class.
30/6/2010       Made Lock()/Unlock() publicly available (mutex of type PTHREAD_MUTEX_ERRORCHECK),
                        in case signal is set with ActivateSignal() this signal will be blocked while locked.
                        Implemented experimental automatic full configuration tracking for Bridge.
7/7/2010        All commandHandler() and rpcHandler() safely translates data into string
                        using ToString(). EvidenceServer class constructor now takes std::string as argument.
                        Removed default configuration file from Config.
19/7/2010       Added documentation. Replaced std::vector by std::map at several locations. Access to
                        class-wide pointer in Message() protected by mutex (currently the memory of the
                        second-last message will not be freed correctly if severity is FATAL). Added
                        History server configuration parameters to adjust buffer size.
20/7/2010       SendToLog() does not call Message() in case of error, but writes error message to log.
21/7/2010       Lock()/Unlock() do not report errors via Message(), but print to console and use 
                        SendToLog(). That avoids a recursion problem since Message() also uses locking.
26/7/2010       General command '/ResetMessage' will reset message text and severity. This feature is
                        used by Alarm if it receives a command to reset an alarm level.
                        ConfigChanged() is called as separate thread when configuration file changes. Thread ID
                        is checked in GetConfig() and also from this thread it will make blocking requests.
12/8/2010       Added command to switch alarm server on/off (command 'Alarm/Switch').
9/12/2010       Minimum period for checking server status in Alarm set to 5 seconds.
2/2/2011        Changed encoding of WARN, ERROR and FATAL to 10,20,30 to allow intermediate values.
                        Non-blocking configuration request with default value was not working.
                        Signal handler calls abort() if invoked three times or more.
10/6/2011       Services can be excluded from History buffer (mainly for large event data services)
20/6/2011       History buffers periodically saved to file (in case program crash or computer reboot)
6/7/2011        Missing pthread_mutexattr_init() in Evidence constructor caused spurious errors when
                        locking mutex
2/8/2011        Used inCallback() method of DIM version v19r23 to decide between blocking or
                        non-blocking config request. Updated EvidenceServer::ToString() for B and V formats.
16/2/2012       EvidenceServer::ToString() handles more complex single-type formats (e.g. "F:1;F:4;F"
18/2/2012       History server detection for minimum change takes an index range given in the configuration
                        into account (e.g. Service:a-b:0.4 requires an minimum absolute change of 0.4 for the average
                        value of indices a to b)
20/2/2012       Disabled padding per default in Evidence class constructor, and also in History and DColl
                        servers. EvidenceServer::ToString() can because of this now handle all format strings.
24/2/2012   Improved interactive behaviour of legend items (drag&drop, context menu). Handling of histories in
                        Edd much faster now. Made a new version Edd:LP for La Palma. History server publishes a list of
                        services subscribed to.
13/6/2012       Removed calling Message() before abort() in signal handler, as Message() might get stuck
19/6/2012   Giving no indices in OpenHistory() will try to open plot for all members of an array
                        If DIM_DNS_NODE not set, EvidenceServer will run in local mode, launching a dns in a separate process on localhost