feat(sdk): add pipeline job placholders for scheduled runs (#8447)

* add pipeline job placeholders

* simplify example code in docs

* add _PLACEHOLDER suffix to variable names

sdk/python/kfp/dsl/__init__.py

@@ -86,7 +86,7 @@
     Example:
       ::
 
-        @dsl.pipeline(name='my-pipeline')
+        @dsl.pipeline
         def my_pipeline():
             print_op(
                 msg='Job name:',
@@ -100,7 +100,7 @@ def my_pipeline():
     Example:
       ::
 
-        @dsl.pipeline(name='my-pipeline')
+        @dsl.pipeline
         def my_pipeline():
             print_op(
                 msg='Job resource name:',
@@ -114,7 +114,7 @@ def my_pipeline():
     Example:
       ::
 
-        @dsl.pipeline(name='my-pipeline')
+        @dsl.pipeline
         def my_pipeline():
             print_op(
                 msg='Job ID:',
@@ -128,7 +128,7 @@ def my_pipeline():
     Example:
       ::
 
-        @dsl.pipeline(name='my-pipeline')
+        @dsl.pipeline
         def my_pipeline():
             print_op(
                 msg='Task name:',
@@ -142,13 +142,40 @@ def my_pipeline():
     Example:
       ::
 
-        @dsl.pipeline(name='my-pipeline')
+        @dsl.pipeline
         def my_pipeline():
             print_op(
                 msg='Task ID:',
                 value=dsl.PIPELINE_TASK_ID_PLACEHOLDER,
             )
 """
+PIPELINE_JOB_CREATE_TIME_UTC_PLACEHOLDER = '{{$.pipeline_job_create_time_utc}}'
+"""A placeholder used to obtain the time that a pipeline job was created.
+
+    Example:
+      ::
+
+        @dsl.pipeline
+        def my_pipeline():
+            print_op(
+                msg='Job created at:',
+                value=dsl.PIPELINE_JOB_CREATE_TIME_UTC,
+            )
+"""
+PIPELINE_JOB_SCHEDULE_TIME_UTC_PLACEHOLDER = '{{$.pipeline_job_schedule_time_utc}}'
+"""A placeholder used to obtain the time for which a pipeline job is scheduled.
+
+    Example:
+      ::
+
+        @dsl.pipeline
+        def my_pipeline():
+            print_op(
+                msg='Job scheduled at:',
+                value=dsl.PIPELINE_JOB_SCHEDULE_TIME_UTC,
+            )
+"""
+
 T = TypeVar('T')
 Input = Annotated[T, InputAnnotation]
 """Type generic used to represent an input artifact of type ``T``, where ``T`` is an artifact class.
@@ -170,7 +197,7 @@ def artifact_producer(model: Output[Artifact]):
     def artifact_consumer(model: Input[Artifact]):
         print(model)
 
-    @dsl.pipeline(name='my-pipeline')
+    @dsl.pipeline
     def my_pipeline():
         producer_task = artifact_producer()
         artifact_consumer(model=producer_task.output)
@@ -196,7 +223,7 @@ def artifact_producer(model: Output[Artifact]):
     def artifact_consumer(model: Input[Artifact]):
         print(model)
 
-    @dsl.pipeline(name='my-pipeline')
+    @dsl.pipeline
     def my_pipeline():
         producer_task = artifact_producer()
         artifact_consumer(model=producer_task.output)