Save experiment outputs + counters as environment variables (#445)

Save run info as environment variables so they can accessed in userscripts

payu/experiment.py

@@ -875,7 +875,22 @@ def resubmit(self):
         cmd = shlex.split(cmd)
         sp.call(cmd)
 
+    def set_userscript_env_vars(self):
+        """Save information of output directories and current run to
+        environment variables, so they can be accessed via user-scripts"""
+        os.environ.update(
+            {
+                'PAYU_CURRENT_OUTPUT_DIR': self.output_path,
+                'PAYU_CURRENT_RESTART_DIR': self.restart_path,
+                'PAYU_ARCHIVE_DIR': self.archive_path,
+                'PAYU_CURRENT_RUN': str(self.counter)
+            }
+        )
+
     def run_userscript(self, script_cmd):
+        # Setup environment variables with current run information
+        self.set_userscript_env_vars()
+
         # First try to interpret the argument as a full command:
         try:
             sp.check_call(shlex.split(script_cmd))