feat(app): add endpoint to verify docker image availability (#990)

Co-authored-by: Tasko Olevski <tasko.olevski@sdsc.ethz.ch>

renku_notebooks/__init__.py

@@ -36,6 +36,7 @@
     VersionResponse,
 )
 from .api.notebooks import (
+    check_docker_image,
     user_servers,
     user_server,
     launch_notebook,
@@ -160,6 +161,7 @@ def register_swagger(app):
         spec.path(view=server_logs)
         spec.path(view=autosave_info)
         spec.path(view=delete_autosave)
+        spec.path(view=check_docker_image)
     # Register security scheme
     security_scheme = {
         "type": "openIdConnect",

renku_notebooks/api/notebooks.py

@@ -23,6 +23,12 @@
 from webargs import fields
 from webargs.flaskparser import use_args
 
+from renku_notebooks.util.check_image import (
+    get_docker_token,
+    image_exists,
+    parse_image_name,
+)
+
 from .. import config
 from .auth import authenticated
 from .schemas import (
@@ -462,3 +468,47 @@ def delete_autosave(user, namespace_project, autosave_name):
         )
     autosave.delete()
     return make_response("", 204)
+
+
+@bp.route("images", methods=["GET"])
+@use_args({"image_url": fields.String(required=True)}, as_kwargs=True, location="query")
+@authenticated
+def check_docker_image(user, image_url):
+    """
+    Return the availability of the docker image.
+
+    ---
+    get:
+      description: Docker image availability.
+      parameters:
+        - in: query
+          schema:
+            type: string
+          required: true
+          name: image_url
+          description: The Docker image URL (tag included) that should be fetched.
+      responses:
+        200:
+          description: The Docker image is available.
+        404:
+          description: The Docker image is not available.
+      tags:
+        - images
+    """
+    parsed_image = parse_image_name(image_url)
+    if parsed_image is None:
+        return (
+            jsonify(
+                {
+                    "message": f"The image {image_url} cannot be parsed, "
+                    "ensure you are providing a valid Docker image name.",
+                }
+            ),
+            422,
+        )
+    token, _ = get_docker_token(**parsed_image, user=user)
+    image_exists_result = image_exists(**parsed_image, token=token)
+    if image_exists_result:
+        return "", 200
+    else:
+        return "", 404

tests/integration/test_image_check_endpoint.py

@@ -0,0 +1,17 @@
+import pytest
+import requests
+
+
+@pytest.mark.parametrize(
+    "image_url,expected_status_code",
+    [("nginx", 200), (":::?-+^", 422), ("image/does_not_exist:9999999999999.99999.9999", 404)],
+)
+def test_image_check_endpoint(
+    image_url,
+    expected_status_code,
+    headers,
+    base_url,
+):
+    url = f"{base_url}/images"
+    res = requests.get(url, headers=headers, params={"image_url": image_url})
+    assert res.status_code == expected_status_code