Logging target from server code?

# 5 years ago
BrianMc	I know how to setup logging targets in a Device Server from a DevProxy. I may have missed it but I have not seen if that can be done from Server code itself - so that a Device Server can control its own logging!

# 5 years ago
Anton	Hi BrianMc Good question. It appear to be possible, although not documented. You can use the `tango.Logging` class to access these kind of things. You can also access the logger instance using `self.get_logger()`, which gives you access to methods like `get_level` and `set_level`. Code for TestLogDS.py: `#!/usr/bin/env python from tango import Logging from tango.server import Device, command class TestLog(Device): @command(dtype_in=str) def custom_add_logging_target(self, target): Logging.add_logging_target([self.get_name(), target]) self.info_stream("Added logging target %s", target)` Run it (without a database): `python -m tango.test_context TestLogDS.TestLog –host 127.0.0.1` Example of usage from ipython: In [1]: import tango In [2]: dp = tango.DeviceProxy('tango://127.0.0.1:8888/test/nodb/testlog#dbase=no') In [3]: dp.get_logging_target() Out[3]: ['console::cout'] In [4]: dp.custom_add_logging_target("file::/tmp/example.log") In [5]: dp.get_logging_target() Out[5]: ['console::cout', 'file::/tmp/example.log'] In [6]: !cat /tmp/example.log <log4j:event logger="test/nodb/testlog" timestamp="1576566408757" level="INFO" thread="140388446758656"> <log4j:message><![CDATA[Added logging target file::/tmp/example.log]]></log4j:message> <log4j:NDC><![CDATA[]]></log4j:NDC> </log4j:event> In [7]: dir(tango.Logging) # to show what methods are available Out[7]: ['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'add_logging_target', 'get_core_logger', 'remove_logging_target', 'start_logging', 'stop_logging'] Looks like that gives us access to this underlying C++ code: https://github.com/tango-controls/cppTango/blob/99bbaa4b5ba4740e4666caf0f7ebc6775f12b799/cppapi/server/logging.cpp#L249

# 5 years ago

Anton

Hi BrianMc

Good question. It appear to be possible, although not documented. You can use the `tango.Logging` class to access these kind of things. You can also access the logger instance using `self.get_logger()`, which gives you access to methods like `get_level` and `set_level`.

Code for TestLogDS.py:


#!/usr/bin/env python

from tango import Logging
from tango.server import Device, command

class TestLog(Device):

    @command(dtype_in=str)
    def custom_add_logging_target(self, target):
        Logging.add_logging_target([self.get_name(), target])
        self.info_stream("Added logging target %s", target)

Run it (without a database):


python -m tango.test_context TestLogDS.TestLog –host 127.0.0.1

Example of usage from ipython:


In [1]: import tango

In [2]: dp = tango.DeviceProxy('tango://127.0.0.1:8888/test/nodb/testlog#dbase=no')

In [3]: dp.get_logging_target()
Out[3]: ['console::cout']

In [4]: dp.custom_add_logging_target("file::/tmp/example.log")

In [5]: dp.get_logging_target()
Out[5]: ['console::cout', 'file::/tmp/example.log']

In [6]: !cat /tmp/example.log
<log4j:event logger="test/nodb/testlog" timestamp="1576566408757" level="INFO" thread="140388446758656">
<log4j:message><![CDATA[Added logging target file::/tmp/example.log]]></log4j:message>
<log4j:NDC><![CDATA[]]></log4j:NDC>
</log4j:event>

In [7]: dir(tango.Logging)  # to show what methods are available
Out[7]:
['__class__',
 '__delattr__',
 '__dict__',
 '__doc__',
 '__format__',
 '__getattribute__',
 '__hash__',
 '__init__',
 '__module__',
 '__new__',
 '__reduce__',
 '__reduce_ex__',
 '__repr__',
 '__setattr__',
 '__sizeof__',
 '__str__',
 '__subclasshook__',
 '__weakref__',
 'add_logging_target',
 'get_core_logger',
 'remove_logging_target',
 'start_logging',
 'stop_logging']

Looks like that gives us access to this underlying C++ code:
https://github.com/tango-controls/cppTango/blob/99bbaa4b5ba4740e4666caf0f7ebc6775f12b799/cppapi/server/logging.cpp#L249

# 5 years ago
BrianMc	Many thanks for the very helpful looking reply - I will follow it in more detail!