tensorboard web-app: Create Tensorboard web-app backend (kubeflow/kubeflow#5180)

* Create Tensorboard web-app backend

Create the code for the Tensorboard web-app backend which
includes routes for GET, POST and DELETE requests.

The backend is created with Python/Flask, so it also uses
the common code from 'kubeflow.kubeflow.crud_backend'.

* Add 'get_age(k8s_object)' function to 'crud_backend' common code

It would be useful for all web apps of the 'crud-web-apps' folder
to return age information to their frontends.

As a result, 'get_age(k8s_object)' was added to the common code,
so that all web apps can use it.

components/crud-web-apps/common/backend/kubeflow/kubeflow/crud_backend/helpers.py

@@ -101,3 +101,18 @@ def get_uptime(then):
                 age = str(mins) + " mins"
 
     return age + " ago"
+
+
+def get_age(k8s_object):
+    """
+    k8s_object: k8s custom resource | dictionary
+
+    Return a dictionary that contains the creationTimestamp (timestamp) of the
+    given k8s object and the amount of time that has passed from that timestamp
+    (uptime).
+    """
+    return {
+        "uptime": get_uptime(
+            k8s_object["metadata"]["creationTimestamp"]),
+        "timestamp": k8s_object["metadata"]["creationTimestamp"],
+    }

components/crud-web-apps/tensorboards/backend/Makefile

@@ -0,0 +1,9 @@
+install-deps:
+	cd ../../common/backend && pip install -e .
+
+run:
+	gunicorn -w 3 --bind 0.0.0.0:5000 --access-logfile - entrypoint:_app
+
+run-dev:
+	BACKEND_MODE=dev \
+	python entrypoint.py

components/crud-web-apps/tensorboards/backend/app/__init__.py

@@ -0,0 +1,17 @@
+import kubeflow.kubeflow.crud_backend as base
+from kubeflow.kubeflow.crud_backend import config, logging
+
+from .routes import bp as routes_bp
+
+log = logging.getLogger(__name__)
+
+
+def create_app(
+    name=__name__, static_folder="static", config_class=config.Config
+):
+    app = base.create_app(name, static_folder, config_class)
+
+    # Register the app's blueprints
+    app.register_blueprint(routes_bp)
+
+    return app

components/crud-web-apps/tensorboards/backend/app/routes/__init__.py

@@ -0,0 +1,5 @@
+from flask import Blueprint
+
+bp = Blueprint("base_routes", __name__)
+
+from . import get, post, delete # noqa E402, F401

components/crud-web-apps/tensorboards/backend/app/routes/delete.py

@@ -0,0 +1,28 @@
+from kubeflow.kubeflow.crud_backend import api, logging
+
+from . import bp
+
+log = logging.getLogger(__name__)
+
+
+@bp.route(
+    "/api/namespaces/<namespace>/tensorboards/<tensorboard>",
+    methods=["DELETE"],
+)
+def delete_tensorboard(tensorboard, namespace):
+
+    log.info("About to delete Tensorboard %s/%s", tensorboard, namespace)
+    api.delete_custom_rsrc(
+        "tensorboard.kubeflow.org",
+        "v1alpha1",
+        "tensorboards",
+        tensorboard,
+        namespace,
+    )
+    log.info(
+        "DELETE request was sent to the API Server for Tensorboard: %s/%s",
+        tensorboard,
+        namespace,
+    )
+
+    return api.success_response("message", "Tensorboard deleted successfully.")

components/crud-web-apps/tensorboards/backend/app/routes/get.py

@@ -0,0 +1,20 @@
+from kubeflow.kubeflow.crud_backend import api, logging
+
+from .. import utils
+from . import bp
+
+log = logging.getLogger(__name__)
+
+
+@bp.route("/api/namespaces/<namespace>/tensorboards")
+def get_tensorboards(namespace):
+
+    tensorboards = api.list_custom_rsrc(
+        "tensorboard.kubeflow.org", "v1alpha1", "tensorboards", namespace
+    )
+    content = [
+        utils.parse_tensorboard(tensorboard)
+        for tensorboard in tensorboards["items"]
+    ]
+
+    return api.success_response("tensorboards", content)

components/crud-web-apps/tensorboards/backend/app/routes/post.py

@@ -0,0 +1,38 @@
+from flask import request
+from kubeflow.kubeflow.crud_backend import (
+    api,
+    decorators,
+    logging,
+)
+
+from .. import utils
+from . import bp
+
+log = logging.getLogger(__name__)
+
+
+@bp.route("/api/namespaces/<namespace>/tensorboards", methods=["POST"])
+@decorators.request_is_json_type
+@decorators.required_body_params("name", "logspath")
+def post_tensorboard(namespace):
+
+    body = request.get_json()
+    log.info("Got body: ", body)
+
+    name = body["name"]
+
+    tensorboard = utils.get_tensorboard_dict(namespace, body)
+
+    log.info("About to create Tensorboard: %s", tensorboard)
+    api.create_custom_rsrc(
+        "tensorboard.kubeflow.org",
+        "v1alpha1",
+        "tensorboards",
+        tensorboard,
+        namespace,
+    )
+    log.info(
+        "Successfully created Tensorboard %s in namespace %s", name, namespace
+    )
+
+    return api.success_response("message", "Tensorboard created successfully.")

components/crud-web-apps/tensorboards/backend/app/utils.py

@@ -0,0 +1,31 @@
+from kubeflow.kubeflow.crud_backend import helpers
+
+
+def parse_tensorboard(tensorboard):
+    """
+    Process the Tensorboard object and format it as the UI expects it.
+    """
+
+    parsed_tensorboard = {
+        "name": tensorboard["metadata"]["name"],
+        "namespace": tensorboard["metadata"]["namespace"],
+        "logspath": tensorboard["spec"]["logspath"],
+        "age": helpers.get_age(tensorboard),
+    }
+
+    return parsed_tensorboard
+
+
+def get_tensorboard_dict(namespace, body):
+    """
+    Create Tensorboard object from request body and format it as a Python dict.
+    """
+
+    tensorboard = {
+        "apiVersion": "tensorboard.kubeflow.org/v1alpha1",
+        "kind": "Tensorboard",
+        "metadata": {"name": body["name"], "namespace": namespace, },
+        "spec": {"logspath": body["logspath"], },
+    }
+
+    return tensorboard

components/crud-web-apps/tensorboards/backend/entrypoint.py

@@ -0,0 +1,20 @@
+import os
+
+from kubeflow.kubeflow.crud_backend import config, logging
+import app
+
+log = logging.getLogger(__name__)
+
+APP_NAME = os.environ.get("APP_NAME", "Tensorboard Web App")
+BACKEND_MODE = os.environ.get("BACKEND_MODE", "prod")  # 'prod' or 'dev'
+
+# Load the Dev config based on BACKEND_MODE env var
+if BACKEND_MODE == "dev":
+    cfg = config.DevConfig
+else:
+    cfg = config.Config
+
+_app = app.create_app(name=APP_NAME, config_class=cfg)
+
+if __name__ == "__main__":
+    _app.run()