Move imagepullsecrets sample to samples/core (#1767)

* Remove redundant import.

* Simplify sample_test.yaml by using withItem syntax.

* Simplify sample_test.yaml by using withItem syntax.

* Change dict to str in withItems.

* Add image pull secret sample.

* Move imagepullsecret sample from test dir to sample dir. Waiting on corresponding unit test infra refactoring.

* Update the location of imagepullsecrets so that it can serve as an example.

* Add minimal comments documenting usage.

sdk/python/tests/compiler/testdata/imagepullsecret.py → samples/core/imagepullsecrets/imagepullsecrets.py

@@ -11,7 +11,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+"""Toy example demonstrating how to specify imagepullsecrets to access protected
+container registry.
+"""
 
 import kfp.dsl as dsl
 from kubernetes import client as k8s_client
@@ -47,4 +49,6 @@ def save_most_frequent_word(message: str):
   counter = GetFrequentWordOp(
           name='get-Frequent',
           message=message)
-  dsl.get_pipeline_conf().set_image_pull_secrets([k8s_client.V1ObjectReference(name="secretA")])
+  # Call set_image_pull_secrets after get_pipeline_conf().
+  dsl.get_pipeline_conf()\
+    .set_image_pull_secrets([k8s_client.V1ObjectReference(name="secretA")])

sdk/python/tests/compiler/compiler_tests.py

@@ -339,9 +339,9 @@ def test_py_retry(self):
     """Test retry functionality."""
     self._test_py_compile_yaml('retry')
 
-  def test_py_image_pull_secret(self):
+  def test_py_image_pull_secrets(self):
     """Test pipeline imagepullsecret."""
-    self._test_py_compile_yaml('imagepullsecret')
+    self._test_sample_py_compile_yaml('imagepullsecrets')
 
   def test_py_timeout(self):
     """Test pipeline timeout."""