CP-46374: Add a minimal observer.py

Signed-off-by: Steven Woods <[email protected]>

scripts/Makefile

@@ -177,6 +177,7 @@ endif
 	sed -i 's/#!\/usr\/bin\/python/#!\/usr\/bin\/python3/' $(DESTDIR)$(SITE3_DIR)/XenAPIPlugin.py
 	$(IDATA) examples/python/XenAPI/XenAPI.py $(DESTDIR)$(SITE3_DIR)/
 	$(IDATA) examples/python/inventory.py $(DESTDIR)$(SITE3_DIR)/
+	$(IDATA) observer.py $(DESTDIR)$(SITE3_DIR)/
 	$(IPROG) examples/python/echo.py $(DESTDIR)$(PLUGINDIR)/echo
 	$(IPROG) examples/python/shell.py $(DESTDIR)$(LIBEXECDIR)/shell.py
 # poweron

scripts/observer.py

@@ -0,0 +1,15 @@
+#!/usr/bin/python3
+
+if __name__ == '__main__':
+  # run a program passed as parameter, with its original arguments
+  import runpy
+  import sys
+
+  # shift all the argvs one left
+  sys.argv = sys.argv[1:]
+  argv0=sys.argv[0]
+
+  def run(file):
+    runpy.run_path(file, run_name='__main__')
+
+  run(argv0)