They likely shouldn't say 'Error' and do increase the noise to signal in the logs. 

The web transactions have a convenience function for getting the most current history for that transaction's user (get_history). If I understand correctly, these messages occur the transaction can't get or create a history ( when no user is currently logged in - or other situations where such as web crawlers).

You can also see these messages in the day-to-day logs of your server, local instance, or the Galaxy main or test servers. As far as I know, they're harmless.
C



On Fri, Jan 25, 2013 at 5:41 AM, Peter Cock <p.j.a.cock@googlemail.com> wrote:
On Tue, Jan 22, 2013 at 4:43 PM, Carl Eberhard <carlfeberhard@gmail.com> wrote:
>>> Short form:
>>> Both the API and client side should handle single datasets error-ing more
>>> gracefully than they did and the history panel should be more resilient and
>>> useful during and after a server error (at least of this kind).
>>>
>>> Please let me know if you see more problems,
>>> C

I'm seeing some (apparently harmless) errors in the output during the 'upload'
step when running Galaxy unit tests - in this case for one of my tools:

functional_tests.py INFO 2013-01-25 10:37:19,810 Functional tests will
be run against localhost:9500
nose.plugins.manager DEBUG 2013-01-25 10:37:19,865
DefaultPluginManager load plugin sqlalchemy =
sqlalchemy.test.noseplugin:NoseSQLAlchemy
nose.plugins.manager DEBUG 2013-01-25 10:37:19,986
DefaultPluginManager load plugin nosetestdiff =
nosetestdiff.plugin:NoseTestDiff
nose.plugins.manager DEBUG 2013-01-25 10:37:19,989
DefaultPluginManager load plugin nosehtml = nosehtml.plugin:NoseHTML
TMHMM 2.0 ( tmhmm2 ) > Test-1 ... galaxy.web.framework DEBUG
2013-01-25 10:37:20,366 Error: this request returned None from
get_history(): http://localhost:9500/
galaxy.web.framework DEBUG 2013-01-25 10:37:20,425 Error: this request
returned None from get_history(): http://localhost:9500/
galaxy.web.framework DEBUG 2013-01-25 10:37:20,676 Error: this request
returned None from get_history(): http://localhost:9500/user/logout
galaxy.web.framework DEBUG 2013-01-25 10:37:20,731 Error: this request
returned None from get_history(): http://localhost:9500/
galaxy.tools.actions.upload_common INFO 2013-01-25 10:37:24,312 tool
upload1 created job id 1
galaxy.jobs.manager DEBUG 2013-01-25 10:37:27,460 (1) Job assigned to
handler 'main'
galaxy.jobs DEBUG 2013-01-25 10:37:32,755 (1) Working directory for
job is: /mnt/galaxy/galaxy-central/database/job_working_directory/000/1
galaxy.jobs.handler DEBUG 2013-01-25 10:37:32,755 dispatching job 1 to
local runner
galaxy.jobs.handler INFO 2013-01-25 10:37:33,041 (1) Job dispatched
galaxy.jobs.runners.local DEBUG 2013-01-25 10:37:33,153 Local runner:
starting job 1
galaxy.jobs.runners.local DEBUG 2013-01-25 10:37:33,712 executing: ...

Are these lines just false positives?
Error: this request returned None from get_history(): http://localhost:9500/
Error: this request returned None from get_history():
http://localhost:9500/user/logout
Error: this request returned None from get_history(): http://localhost:9500/

Thanks,

Peter