arcpy.GetMessages returns empty [BUG]

Question

I am trying to access the messages that were logged throughout a script.
arcpy.AddMessage("Something...")
message = arcpy.GetMessages()
print message  # always empty

The above is always empty.

According to the documentation [http://resources.arcgis.com/en/help/main/10.1/index.html#/AddMessage/018v00000007000000/]Creates a geoprocessing informative message (Severity=0) that can be accessed with any of the GetMessages functions.

What am I missing here?

I'm starting to think this is either a bug or something not documented.

XanderBakker · Answer

Hi Tony,

I can't find where this information is stored. Maybe some implementation of the logging module, although most of the functionality goes through ArcObjects...

I guess it's not so hard to implement an alternative, but if you want to keep using the messaging of arcpy, it might be wise to contact Esri support and report the bug. Maybe in a future release they fix the bug, or change the help text 😉

Kind regards,

Xander

Matrix_Solutions_Inc_Geomatics · Answer

Thanks for the quick reply.

Would you happen to know if the messages get written somewhere else in the interpreter? or rather, the ultimate place that they trickle down to?

I tried redirecting sys.stdout / sys.stderr but it seem arcpy.AddMessage doesn't seem to write to there either. However, there must be a standard Python object that receives the messages because my IDE console always displays them.

XanderBakker · Answer

What then does the documentation refer to ?

You are completely right. I does not seem to do what is described in the help. Even the slightly change sample script does not return what one should expect based on the description.import arcpy
fc = r'C:\Project\_Forums\ZonStatPol	est.gdb\Intersect'
feature_count = int(arcpy.GetCount_management(fc).getOutput(0))

if feature_count == 0:
    arcpy.AddError("{0} has no features.".format(fc))
else:
    arcpy.AddMessage("{0} has {1} features.".format(fc, feature_count))

print arcpy.GetMessages()

Results in:

Executing: GetCount C:\Project\_Forums\ZonStatPol	est.gdb\Intersect
Start Time: Tue Feb 25 15:46:45 2014
Row Count = 10
Succeeded at Tue Feb 25 15:46:45 2014 (Elapsed Time: 0,19 seconds)

... which is the output of the geoprocessing tool GetCount_management

Said, but true (or I simply don't get it).

Kind regards,

Xander