EasyBlock: Allow to pass logfile from other EasyBlock

In the case an EasyBlock creates another instance of an EasyBlock (for
example when dealing with Bundles), each instance will create new
log file, which may stay open and cause issues down the line. To
prevent this, add an option to the EasyBlock constructor to pass a
logfile from another EasyBlock.

Signed-off-by: Jan André Reuter <j.reuter@fz-juelich.de>

easybuild/framework/easyblock.py

@@ -40,6 +40,7 @@
 * Maxime Boissonneault (Compute Canada)
 * Davide Vanzo (Vanderbilt University)
 * Caspar van Leeuwen (SURF)
+* Jan Andre Reuter (Juelich Supercomputing Centre)
 """
 
 import copy
@@ -141,10 +142,11 @@ def extra_options(extra=None):
     #
     # INIT
     #
-    def __init__(self, ec):
+    def __init__(self, ec, logfile=None):
         """
         Initialize the EasyBlock instance.
         :param ec: a parsed easyconfig file (EasyConfig instance)
+        :param logfile: pass logfile from other EasyBlock. If not passed, create logfile (optional)
         """
 
         # keep track of original working directory, so we can go back there
@@ -214,7 +216,8 @@ def __init__(self, ec):
 
         # logging
         self.log = None
-        self.logfile = None
+        self.logfile = logfile
+        self.external_logfile = logfile is not None
         self.logdebug = build_option('debug')
         self.postmsg = ''  # allow a post message to be set, which can be shown as last output
         self.current_step = None
@@ -303,11 +306,11 @@ def _init_log(self):
         if self.log is not None:
             return
 
-        self.logfile = get_log_filename(self.name, self.version, add_salt=True)
-        fancylogger.logToFile(self.logfile, max_bytes=0)
+        if self.logfile is None:
+            self.logfile = get_log_filename(self.name, self.version, add_salt=True)
+            fancylogger.logToFile(self.logfile, max_bytes=0)
 
         self.log = fancylogger.getLogger(name=self.__class__.__name__, fname=False)
-
         self.log.info(this_is_easybuild())
 
         this_module = inspect.getmodule(self)
@@ -323,6 +326,9 @@ def close_log(self):
         """
         Shutdown the logger.
         """
+        # only close log if we created a logfile
+        if self.external_logfile:
+            return
         self.log.info("Closing log for application name %s version %s" % (self.name, self.version))
         fancylogger.logToFile(self.logfile, enable=False)
 

test/framework/easyblock.py

@@ -28,6 +28,7 @@
 @author: Jens Timmerman (Ghent University)
 @author: Kenneth Hoste (Ghent University)
 @author: Maxime Boissonneault (Compute Canada)
+@author: Jan Andre Reuter (Juelich Supercomputing Centre)
 """
 import os
 import re
@@ -2895,6 +2896,47 @@ def run_sanity_check_step(sanity_check_paths, enhance_sanity_check):
         run_sanity_check_step({}, False)
         run_sanity_check_step({}, True)
 
+    def test_create_easyblock_without_logfile(self):
+        """
+        Test creating an EasyBlock without a logfile.
+        This represents scenarios found in Bundle and QuantumESPRESSO, where an EasyBlock is
+        created within another EasyBlock.
+        """
+        self.contents = '\n'.join([
+            'easyblock = "ConfigureMake"',
+            'name = "pi"',
+            'version = "3.14"',
+            'homepage = "http://example.com"',
+            'description = "test easyconfig"',
+            'toolchain = SYSTEM',
+        ])
+        self.writeEC()
+        # Ensure that the default case works as expected
+        eb = EasyBlock(EasyConfig(self.eb_file))
+        self.assertNotEqual(eb.log, None)
+        self.assertNotEqual(eb.logfile, None)
+        # Get reference to the actual log instance and ensure that it works
+        # This is NOT eb.log, which represents a separate logger with a separate name.
+        file_log = fancylogger.getLogger(name=None)
+        self.assertNotEqual(getattr(file_log, 'logtofile_%s' % eb.logfile), False)
+
+        # Now, create another EasyBlock by passing logfile from first EasyBlock.
+        eb_external_logfile = EasyBlock(EasyConfig(self.eb_file), logfile=eb.logfile)
+        self.assertNotEqual(eb_external_logfile.log, None)
+        self.assertTrue(eb_external_logfile.external_logfile)
+        self.assertEqual(eb_external_logfile.logfile, eb.logfile)
+        # Try to log something in it.
+        eb_external_logfile.log.info("Test message")
+
+        # Try to close EasyBlock with external logfile. This should not affect the logger.
+        eb_external_logfile.close_log()
+        self.assertNotEqual(getattr(file_log, 'logtofile_%s' % eb.logfile), False)
+        # Then close the log from creating EasyBlock. This should work as expected.
+        eb.close_log()
+        self.assertEqual(getattr(file_log, 'logtofile_%s' % eb.logfile), False)
+
+        os.remove(eb.logfile)
+
 
 def suite():
     """ return all the tests in this file """