Python: Copy Python extractor to codeql repo

python/extractor/python_tracer.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+
+#This file needs to be able to handle all versions of Python we are likely to encounter
+#Which is probably 2.6 and upwards
+
+'''This module sets up sys.path from the environment
+and runs the populator when called from semmle tools such as buildSnapshot.'''
+
+import sys
+import os
+
+# The constant is put here instead of make_zips.py, since make_zips.py is not present in
+# the distributed extractor-python code
+def getzipfilename():
+    return 'python3src.zip'
+
+
+def load_library():
+    try:
+        tools = os.environ['ODASA_TOOLS']
+    except KeyError:
+        try:
+            tools = os.path.join(os.environ['SEMMLE_DIST'], "tools")
+        except KeyError:
+            tools = sys.path[0]
+    try:
+        zippath = os.path.join(tools, getzipfilename())
+        sys.path = [ zippath ] + sys.path
+    except Exception:
+        #Failed to find tools. Error is reported below
+        zippath = tools
+    try:
+        import semmle.populator
+    except ImportError as ex:
+        print("FATAL ERROR: ")
+        print(ex)
+        if tools is not None:
+            if not os.path.exists(os.path.join(tools, getzipfilename())):
+                sys.stderr.write("No tracer library found in " + tools + "\n")
+            else:
+                sys.stderr.write("Unable to load tracer library at %s:\n" % zippath)
+                import traceback
+                traceback.print_exc(file=sys.stderr)
+        else:
+            print(sys.path)
+            sys.stderr.write("Cannot find Semmle tools\n")
+        sys.exit(2)
+
+if __name__ == "__main__":
+    original_path = sys.path
+    load_library()
+    import semmle.populator
+    semmle.populator.main(original_path)