Create a script to make updating application resources easier. (kubef…

…low#596)

* This is a replacement for
  https://github.com/kubeflow/manifests/blob/master/hack/update-instance-labels.sh

* We don't want to assume all applications are at the same version
* This script makes it easier to set a different version for a specific
  application.

py/kubeflow/testing/tools/applications.py

@@ -0,0 +1,79 @@
+"""A CLI for updating YAML files defining application CRs.
+
+This tool makes it easier to update and maintain the Application CRs
+for each application.
+"""
+
+import fire
+import logging
+import os
+import yaml
+
+class AppManager:
+  @staticmethod
+  def update(version, directory=None):
+    """Update the application resources to the specified version.
+
+    Args:
+      version: The version to set
+      directory: (Optional). Directory to run in defaults to current directory.
+    """
+
+    if not directory:
+      directory = os.getcwd()
+
+    logging.info(f"Looking for application.yaml files in {directory}")
+
+    for base, _, files in os.walk(directory):
+      for f in files:
+        if f != "application.yaml":
+          continue
+
+        path = os.path.join(base, f)
+
+        logging.info(f"Processing {path}")
+
+        with open(path) as hf:
+          app = yaml.load(hf)
+
+        labels = app["spec"]["selector"]["matchLabels"]
+        app_name = labels.get("app.kubernetes.io/name", "")
+
+        labels["app.kubernetes.io/version"] = version
+        labels["app.kubernetes.io/instance"] = (
+          f"{app_name}-{version}")
+
+        with open(path, "w") as hf:
+          yaml.dump(app, hf)
+
+        # We also need to modify the kustomization file to add the labels
+        kustomization_path = os.path.join(base, "kustomization.yaml")
+
+        if not os.path.exists(kustomization_path):
+          logging.warning(f"kustomizatin file: {kustomization_path} doesn't "
+                          f"exist")
+
+        with open(kustomization_path) as hf:
+          kustomize = yaml.load(hf)
+
+        if "commonLabels" not in kustomize:
+          kustomize["commonLabels"] = {}
+
+        kustomize["commonLabels"]["app.kubernetes.io/version"] = version
+        kustomize["commonLabels"]["app.kubernetes.io/instance"] = (
+          f"{app_name}-{version}")
+
+        logging.info(f"Updating {kustomization_path}")
+
+        with open(kustomization_path, "w") as hf:
+          yaml.dump(kustomize, hf)
+
+if __name__ == "__main__":
+
+  logging.basicConfig(level=logging.INFO,
+                      format=('%(levelname)s|%(asctime)s'
+                              '|%(message)s|%(pathname)s|%(lineno)d|'),
+                      datefmt='%Y-%m-%dT%H:%M:%S',
+                      )
+
+  fire.Fire(AppManager)