Support Post sart up script on runtime templates (#15934)

Author: bcreddy-gcp

mmv1/products/colab/RuntimeTemplate.yaml

@@ -209,3 +209,20 @@ properties:
                             If a variable cannot be resolved, the reference in the input string will be unchanged.
                             The $(VAR_NAME) syntax can be escaped with a double $$, ie: $$(VAR_NAME). Escaped
                             references will never be expanded, regardless of whether the variable exists or not.'
+      - name: 'postStartupScriptConfig'
+        type: NestedObject
+        description: 'Post startup script config.'
+        properties:
+          - name: 'postStartupScript'
+            type: String
+            description: 'Post startup script to run after runtime is started.'
+          - name: 'postStartupScriptUrl'
+            type: String
+            description: 'Post startup script url to download. Example: https://bucket/script.sh.'
+          - name: 'postStartupScriptBehavior'
+            type: Enum
+            description: 'Post startup script behavior that defines download and execution behavior.'
+            enum_values:
+              - 'RUN_ONCE'
+              - 'RUN_EVERY_START'
+              - 'DOWNLOAD_AND_RUN_EVERY_START'

mmv1/templates/terraform/examples/colab_runtime_template_full.tf.tmpl

@@ -53,4 +53,17 @@ resource "google_colab_runtime_template" "{{$.PrimaryResourceId}}" {
   encryption_spec {
     kms_key_name = "{{index $.Vars "key_name"}}"
   }
+
+  software_config {
+    env {
+      name    = "TEST"
+      value   = 1
+    }
+
+    post_startup_script_config {
+      post_startup_script = "echo 'hello world'"
+      post_startup_script_url = "gs://colab-enterprise-pss-secure/secure_pss.sh"
+      post_startup_script_behavior = "RUN_ONCE"
+    }
+  }
 }