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author | Chris St. Pierre <chris.a.st.pierre@gmail.com> | 2012-11-29 14:45:03 -0500 |
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committer | Chris St. Pierre <chris.a.st.pierre@gmail.com> | 2012-11-29 14:45:03 -0500 |
commit | 8cbe248150ba99fff310ae099593202ee1da65ce (patch) | |
tree | e00d8a8dfa024ec9e2d6380aae2a6fbcebce0150 /src/lib/Bcfg2/Server | |
parent | d0e299bb298f1b675dd37d4e42c95ab5117c978e (diff) | |
download | bcfg2-8cbe248150ba99fff310ae099593202ee1da65ce.tar.gz bcfg2-8cbe248150ba99fff310ae099593202ee1da65ce.tar.bz2 bcfg2-8cbe248150ba99fff310ae099593202ee1da65ce.zip |
Cfg: Fixed bugs in Genshi error handling:
* Find the correct frame of the stack trace if the exception is raised by something outside the template
* Determine if the version of Genshi in use strips all blank lines or not to correctly locate the line of the error
Diffstat (limited to 'src/lib/Bcfg2/Server')
-rw-r--r-- | src/lib/Bcfg2/Server/Plugins/Cfg/CfgGenshiGenerator.py | 65 |
1 files changed, 54 insertions, 11 deletions
diff --git a/src/lib/Bcfg2/Server/Plugins/Cfg/CfgGenshiGenerator.py b/src/lib/Bcfg2/Server/Plugins/Cfg/CfgGenshiGenerator.py index 3a78b4847..73550cd9d 100644 --- a/src/lib/Bcfg2/Server/Plugins/Cfg/CfgGenshiGenerator.py +++ b/src/lib/Bcfg2/Server/Plugins/Cfg/CfgGenshiGenerator.py @@ -11,8 +11,39 @@ from Bcfg2.Server.Plugins.Cfg import CfgGenerator, SETUP try: import genshi.core from genshi.template import TemplateLoader, NewTextTemplate - from genshi.template.eval import UndefinedError + from genshi.template.eval import UndefinedError, Suite + #: True if Genshi libraries are available HAS_GENSHI = True + + def _genshi_removes_blank_lines(): + """ Genshi 0.5 uses the Python :mod:`compiler` package to + compile genshi snippets to AST. Genshi 0.6 uses some bespoke + magic, because compiler has been deprecated. + :func:`compiler.parse` produces an AST that removes all excess + whitespace (e.g., blank lines), while + :func:`genshi.template.astutil.parse` does not. In order to + determine which actual line of code an error occurs on, we + need to know which is in use and how it treats blank lines. + I've beat my head against this for hours and the best/only way + I can find is to compile some genshi code with an error and + see which line it's on.""" + code = """d = dict() + +d['a']""" + try: + Suite(code).execute(dict()) + except KeyError: + line = traceback.extract_tb(sys.exc_info()[2])[-1][1] + if line == 2: + return True + else: + return False + + #: True if Genshi removes all blank lines from a code block before + #: executing it; False indicates that Genshi only removes leading + #: and trailing blank lines. See + #: :func:`_genshi_removes_blank_lines` for an explanation of this. + GENSHI_REMOVES_BLANK_LINES = _genshi_removes_blank_lines() except ImportError: TemplateLoader = None # pylint: disable=C0103 HAS_GENSHI = False @@ -111,7 +142,17 @@ class CfgGenshiGenerator(CfgGenerator): # the traceback is just the beginning of the block. err = exc[1] stack = traceback.extract_tb(exc[2]) - lineno, func = stack[-1][1:3] + + # find the right frame of the stack + for frame in reversed(stack): + if frame[0] == self.name: + lineno, func = frame[1:3] + break + else: + # couldn't even find the stack frame, wtf. + raise PluginExecutionError("%s: %s" % + (err.__class__.__name__, err)) + execs = [contents for etype, contents, _ in self.template.stream if etype == self.template.EXEC] @@ -129,18 +170,20 @@ class CfgGenshiGenerator(CfgGenerator): # else, no EXEC blocks -- WTF? if contents: # we now have the bogus block, but we need to get the - # offending line. To get there, we do (line number - # given in the exception) - (firstlineno from the - # internal genshi code object of the snippet) + 1 = - # (line number of the line with an error within the - # block, with all multiple line breaks elided to a - # single line break) - real_lineno = lineno - contents.code.co_firstlineno - src = re.sub(r'\n\n+', '\n', contents.source).splitlines() + # offending line. To get there, we do (line number given + # in the exception) - (firstlineno from the internal + # genshi code object of the snippet) = (line number of the + # line with an error within the block, with blank lines + # removed as appropriate for + # :attr:`GENSHI_REMOVES_BLANK_LINES`) + code = contents.source.strip().splitlines() + if GENSHI_REMOVES_BLANK_LINES: + code = [l for l in code if l.strip()] try: + line = code[lineno - contents.code.co_firstlineno] raise PluginExecutionError("%s: %s at '%s'" % (err.__class__.__name__, err, - src[real_lineno])) + line)) except IndexError: raise PluginExecutionError("%s: %s" % (err.__class__.__name__, err)) |