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Logger - yet an other Variable Logging Utility
The Logger (logger.c)
The logger is a utility to write the history of object parameters. For all
drivers based on pardef it is automatically switched on. The data is logged
typically every 5 seconds to a file, but only changes are stored in order to save
disk space. The file specification for the logfiles is:
<logger base path>/<variable name>/MM-DD.log
Files older than one year will be overwritten. The variable name is the object name for
the basic value of the object or <object name>.<parameter name> for the parameters.
Important parameter names might be configured to have a more descriptive name.
Syntax of the Log Files
First there is a header line, containing the date and some additional information:
- isdst
- 0/1 when daylight saving time is in effect or not
- period
- the minimal interval between logged values
- exact
- 0: plot points should be connected with a straight line, 1: plot curves should have only horizontal and vertical lines
For every logger entry, there is one line, containing the time, a tab as separation and a value, (which may be a text or number). There may also be lines starting with a hash
symbol, which may contain the same information as in the header line, or just a comment.
#2005-10-30 00:00:00 isdst 1 period 5 exact 0
00:00:00 100.72
00:00:05 100.73
00:01:10 100.73
00:01:15 100.74
00:01:20 100.73
... many lines omitted
02:59:55 100.56
#isdst 0 change of daylight saving time
02:00:00 100.58
... many lines omitted
07:55:00 100.58 the server was shut down
#period 5 exact 0 isdst 0 the server restarts at 8:30
07:55:05 the shutdown time and an empty value
08:30:00 99.95 the first logged value after startup
The Log Reader (logreader.c)
There is also a utility to read the logged data through the SICS server.
This particular version was published on 15-Sep-2005 07:16:45 UTC by MarkusZolliker.
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