[AIRFLOW-6245] Add custom waiters for AWS batch jobs

UPDATING.md

@@ -253,11 +253,31 @@ Migrated are:
 | airflow.contrib.hooks.aws_sns_hook.AwsSnsHook                   | airflow.providers.amazon.aws.hooks.sns.AwsSnsHook        |
 | airflow.contrib.operators.aws_athena_operator.AWSAthenaOperator | airflow.providers.amazon.aws.operators.athena.AWSAthenaOperator |
 | airflow.contrib.operators.awsbatch.AWSBatchOperator | airflow.providers.amazon.aws.operators.batch.AwsBatchOperator |
+| airflow.contrib.operators.awsbatch.BatchProtocol | airflow.providers.amazon.aws.hooks.batch_client.AwsBatchProtocol |
+| private attrs and methods on AWSBatchOperator | airflow.providers.amazon.aws.hooks.batch_client.AwsBatchClient |
+| n/a | airflow.providers.amazon.aws.hooks.batch_waiters.AwsBatchWaiters |
 | airflow.contrib.operators.aws_sqs_publish_operator.SQSPublishOperator | airflow.providers.amazon.aws.operators.sqs.SQSPublishOperator |
 | airflow.contrib.operators.aws_sns_publish_operator.SnsPublishOperator | airflow.providers.amazon.aws.operators.sns.SnsPublishOperator |
 | airflow.contrib.sensors.aws_athena_sensor.AthenaSensor       | airflow.providers.amazon.aws.sensors.athena.AthenaSensor        |
 | airflow.contrib.sensors.aws_sqs_sensor.SQSSensor             | airflow.providers.amazon.aws.sensors.sqs.SQSSensor        |
 
+### AWS Batch Operator
+
+The `AwsBatchOperator` was refactored to extract an `AwsBatchClient` (and inherit from it).  The
+changes are mostly backwards compatible and clarify the public API for these classes; some
+private methods on `AwsBatchOperator` for polling a job status were relocated and renamed
+to surface new public methods on `AwsBatchClient` (and via inheritance on `AwsBatchOperator`).  A
+couple of job attributes are renamed on an instance of `AwsBatchOperator`; these were mostly
+used like private attributes but they were surfaced in the public API, so any use of them needs
+to be updated as follows:
+- `AwsBatchOperator().jobId` -> `AwsBatchOperator().job_id`
+- `AwsBatchOperator().jobName` -> `AwsBatchOperator().job_name`
+
+The `AwsBatchOperator` gets a new option to define a custom model for waiting on job status changes.
+The `AwsBatchOperator` can use a new `waiters` parameter, an instance of `AwsBatchWaiters`, to
+specify that custom job waiters will be used to monitor a batch job.  See the latest API
+documentation for details.
+
 ### Additional arguments passed to BaseOperator cause an exception
 
 Previous versions of Airflow took additional arguments and displayed a message on the console. When the

airflow/contrib/operators/awsbatch_operator.py

@@ -18,14 +18,25 @@
 # under the License.
 #
 
-"""This module is deprecated. Please use `airflow.providers.amazon.aws.operators.batch`."""
+"""This module is deprecated. Please use:
+
+  - `airflow.providers.amazon.aws.operators.batch`
+  - `airflow.providers.amazon.aws.hooks.batch_client`
+  - `airflow.providers.amazon.aws.hooks.batch_waiters`
+"""
 
 import warnings
 
+from typing_extensions import Protocol, runtime_checkable
+
+from airflow.providers.amazon.aws.hooks.batch_client import AwsBatchProtocol
 from airflow.providers.amazon.aws.operators.batch import AwsBatchOperator
 
 warnings.warn(
-    "This module is deprecated. Please use `airflow.providers.amazon.aws.operators.batch`.",
+    "This module is deprecated. "
+    "Please use `airflow.providers.amazon.aws.operators.batch`, "
+    "`airflow.providers.amazon.aws.hooks.batch_client`, and "
+    "`airflow.providers.amazon.aws.hooks.batch_waiters`",
     DeprecationWarning,
     stacklevel=2,
 )
@@ -44,3 +55,20 @@ def __init__(self, *args, **kwargs):
             stacklevel=2,
         )
         super().__init__(*args, **kwargs)
+
+
+@runtime_checkable
+class BatchProtocol(AwsBatchProtocol, Protocol):
+    """
+    This class is deprecated. Please use `airflow.providers.amazon.aws.hooks.batch_client.AwsBatchProtocol`.
+    """
+
+    # A Protocol cannot be instantiated
+
+    def __new__(cls, *args, **kwargs):
+        warnings.warn(
+            """This class is deprecated.
+            Please use `airflow.providers.amazon.aws.hooks.batch_client.AwsBatchProtocol`.""",
+            DeprecationWarning,
+            stacklevel=2,
+        )