MessageLogger Tutorial Examples

Contents

• Sending Warnings and Error Messages to a File
• Explanation

Sending Warnings and Error Messages to a File

# warningsToMyOutputFile.py
# -------------------------------

import FWCore.ParameterSet.Config as cms
process.MessageLogger = cms.Service("MessageLogger",
        destinations = cms.untracked.vstring(                           #1
                'myOutputFile'                                          #2
        ),
        myOutputFile = cms.untracked.PSet(                              #3
                threshold = cms.untracked.string( 'WARNINGS' )          #4
        ),
)                                                                       #5

# set the number of events
process.maxEvents = cms.untracked.PSet(
    input = cms.untracked.int32(200)
)
 
process.myAnalysisModule = cms.EDAnalyzer('ModuleThatIssuesMessages')
process.p = cms.Path(process.myAnalysisModule)

Explanation:

In the above example, one file, named myOutputFile.log, would be produced.

On line 1, we define a vstring named destinations=cms.untracked.vstring(... . Every confugration file should have this vstring defined; the name destinations is a keyword telling the logger that one or more files for output are going to be created.

On line 2, we name a file destination. In this example, this is the only destination we name. Two special names could have been used here: cerr or cout. Those would not produce files; they would route the output to cerr or cout.

On line 3, we start a PSet with a name matching one of the destinations we had specified. In this case, that name is myOutputFile. The contents of this PSet will control the behavior of just that destination. The name of the file produced will be taken from the name of the destination; by default, the logger adds the extension .log. (A later example will explain how to get an extension other than .log, or a file name other than the name of the destination PSet, if you want.)

On line 4, we are controlling the behavior of this destination. In this case, we are saying that the threshold for responding to messages issues is at the level of WARNING. This means that this destination will respond to (and output) message issued via edm::LogWarning and anything at least that serious. (For example, edm::LogPrint, edm::LogError, edm::LogProblem, and edm::LogImportant will lead to output.) But levels less severe than WARNING will not appear. For example, edm::LogInfo and edm::LogVerbatim will have no effect on this destination.

Line 5 completes the configuration of the MessageLogger. The other lines of this example are generic lines to tell cmsRun how many events to process, which modules to use, and so forth.

-- MarkFischler - 12-Aug-2010