Make batch job runnables a list instead of single string

This way toolkit users can deploy batch jobs with multiple runnables.
This can be convenient, for example, when the user wants to install
something wih an initial "apt install" or "yum install" before running
the "real" workload.

examples/serverless-batch-mpi.yaml

@@ -150,7 +150,9 @@ deployment_groups:
     source: modules/scheduler/batch-job-template
     use: [network1, sharefs]
     settings:
-      runnable: . /share/wrfv3/submit_wrfv3.sh;
+      runnables:
+      - id: run WRF
+        script: . /share/wrfv3/submit_wrfv3.sh;
       machine_type: c2-standard-60
       task_count: 2
       mpi_mode: true

examples/serverless-batch.yaml

@@ -39,9 +39,11 @@ deployment_groups:
     source: modules/scheduler/batch-job-template
     use: [network1, appfs]
     settings:
-      runnable: |
-        mkdir -p /sw/$BATCH_JOB_UID
-        echo "Hello World from task $BATCH_TASK_INDEX" > /sw/$BATCH_JOB_UID/$BATCH_TASK_INDEX.txt
+      runnables:
+      - id: step 1
+        script: |
+          mkdir -p /sw/$BATCH_JOB_UID
+          echo "Hello World from task $BATCH_TASK_INDEX" > /sw/$BATCH_JOB_UID/$BATCH_TASK_INDEX.txt
       machine_type: n2-standard-4
       task_count: 8
       task_count_per_node: 4

modules/scheduler/batch-job-template/main.tf

@@ -28,7 +28,7 @@ locals {
     "${path.module}/templates/batch-job-base.yaml.tftpl",
     {
       synchronized       = var.mpi_mode
-      runnable           = var.runnable
+      runnables          = var.runnables
       task_count         = var.task_count
       tasks_per_node     = local.tasks_per_node
       require_hosts_file = var.mpi_mode

modules/scheduler/batch-job-template/templates/batch-job-base.yaml.tftpl

@@ -5,12 +5,14 @@ taskGroups:
         - barrier:
             name: "wait-for-node-startup"
         %{~ endif ~}
+        %{~ for runnable in runnables ~}
         - script:
-            text: ${indent(12, chomp(yamlencode(runnable)))}
+            text: ${indent(12, chomp(yamlencode(runnable.script)))}
         %{~ if synchronized ~}
         - barrier:
-            name: "wait-for-workload-to-complete"
+            name: "wait-for-script-to-complete"
         %{~ endif ~}
+        %{~ endfor ~}
         %{~ if length(nfs_volumes) > 0 ~}
         volumes:
         %{~ for index, vol in nfs_volumes ~}

modules/scheduler/batch-job-template/variables.tf

@@ -91,10 +91,16 @@ variable "log_policy" {
   }
 }
 
-variable "runnable" {
-  description = "A string to be executed as the main workload of the Google Cloud Batch job. This will be used to populate the generated template."
-  type        = string
-  default     = "## Add your workload here"
+variable "runnables" {
+  description = "A list of shell scripts to be executed in sequence as the main workload of the Google Cloud Batch job. These will be used to populate the generated template."
+  type = list(object({
+    script = string
+  }))
+  default = [
+    {
+      script: "## Add your workload here"
+    }
+  ]
 }
 
 variable "instance_template" {