Handle nonexistant analyzers

Trying to submit to an analyzer that is not configured results in an
AttributeError because property id of the analyzer object is accessed
regardless of the result of get_by_name:

  File "/cortex4py/cortex4py/controllers/analyzers.py", line 90, in run_by_name
    return self.run_by_id(analyzer.id, observable, **kwargs)
AttributeError: 'NoneType' object has no attribute 'id'

Add a check for the result of get_by_name() and throw a CortexError with
explanatory message on failure.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>

Author: michaelweiser

cortex4py/controllers/analyzers.py

@@ -7,6 +7,7 @@
 from cortex4py.query import *
 from .abstract import AbstractController
 from ..models import Analyzer, Job, AnalyzerDefinition
+from ..exceptions import CortexError
 
 
 class AnalyzersController(AbstractController):
@@ -87,4 +88,7 @@ def run_by_id(self, analyzer_id, observable, **kwargs) -> Job:
     def run_by_name(self, analyzer_name, observable, **kwargs) -> Job:
         analyzer = self.get_by_name(analyzer_name)
 
+        if analyzer is None:
+            raise CortexError("Analyzer %s not found" % analyzer_name)
+
         return self.run_by_id(analyzer.id, observable, **kwargs)