Add auto-discovery to working_set; add safeties (#97)

Author: pglombardo

instana/__init__.py

@@ -1,7 +1,8 @@
 from __future__ import absolute_import
 
 import os
-from pkg_resources import get_distribution
+import pkg_resources
+
 
 """
 The Instana package has two core components: the agent and the tracer.
@@ -22,14 +23,20 @@
   Recorder
 """
 
+pkg_resources.working_set.add_entry("/tmp/instana/python")
+
 __author__ = 'Instana Inc.'
 __copyright__ = 'Copyright 2017 Instana Inc.'
 __credits__ = ['Pavlo Baron', 'Peter Giacomo Lombardo']
 __license__ = 'MIT'
-__version__ = get_distribution('instana').version
 __maintainer__ = 'Peter Giacomo Lombardo'
 __email__ = '[email protected]'
 
+try:
+    __version__ = pkg_resources.get_distribution('instana').version
+except pkg_resources.DistributionNotFound:
+    __version__ = 'unknown'
+
 
 def load(module):
     """

instana/fsm.py

@@ -8,9 +8,11 @@
 import threading as t
 
 import fysom as f
-from pkg_resources import get_distribution
+import pkg_resources
 
-from .agent_const import AGENT_HEADER, AGENT_DISCOVERY_URL, AGENT_DATA_URL, AGENT_DEFAULT_HOST, AGENT_DEFAULT_PORT
+from .agent_const import (AGENT_DATA_URL, AGENT_DEFAULT_HOST,
+                          AGENT_DEFAULT_PORT, AGENT_DISCOVERY_URL,
+                          AGENT_HEADER)
 from .log import logger
 
 
@@ -44,8 +46,13 @@ class Fsm(object):
     warnedPeriodic = False
 
     def __init__(self, agent):
-        logger.info("Stan is on the scene.  Starting Instana instrumentation version: %s" %
-                    get_distribution('instana').version)
+        package_version = 'unknown'
+        try:
+            package_version = pkg_resources.get_distribution('instana').version
+        except pkg_resources.DistributionNotFound:
+            pass
+
+        logger.info("Stan is on the scene.  Starting Instana instrumentation version: %s" % package_version)
         logger.debug("initializing fsm")
 
         self.agent = agent