Allow for injecting arbitrary sbatch headers

var/ramble/repos/builtin/workflow_managers/slurm/workflow_manager.py

@@ -61,6 +61,7 @@ class Slurm(WorkflowManagerBase):
     def _slurm_execute_script(self):
         headers = ["#!/bin/bash"]
         expander = self.app_inst.expander
+        # Adding pre-defined sets of headers
         pragmas = [
             ("#SBATCH -N {}", "n_nodes"),
             ("#SBATCH -p {}", "partition"),
@@ -82,6 +83,18 @@ def _slurm_execute_script(self):
                 # Skip a particular header if any of the vars are not defined
                 continue
             headers.append(tpl.format(*vals))
+        # Adding extra arbitrary headers
+        try:
+            extra_sbatch_headers_raw = expander.expand_var_name(
+                "extra_sbatch_headers", allow_passthrough=False
+            )
+            extra_sbatch_headers = extra_sbatch_headers_raw.strip().split("\n")
+            extra_headers = [
+                expander.expand_var(h) for h in extra_sbatch_headers
+            ]
+            headers = headers + extra_headers
+        except ExpanderError:
+            pass
         header_str = "\n".join(headers)
         content = rf"""
 {header_str}