Fixes cc-archive#487(image index availability check)

CONTRIBUTING.md

@@ -32,7 +32,7 @@ Before you start writing code, make sure there is an issue open. Pull requests w
 
 If you want to get started contributing code to this project but don't know exactly what to work on, we compiled a good list of issues labeled as [Good first issues](https://github.com/creativecommons/cccatalog-frontend/labels/good%20first%20issue) which are small in scope and not so complex to solve. There is also issues labeld as [Help wanted](https://github.com/creativecommons/cccatalog-frontend/labels/help%20wanted) which can be a bit more complex but are good examples of thigns we are currently accepting help from the community.
 
-Any code modifications will have to be accompanied by the appropriate unit tests. This will be checked and verified during code review. Once the Pull Reques is opened, our CI server will run the unit test suite and run a code linter to verify that the code follows the coding guidelines.
+Any code modifications will have to be accompanied by the appropriate unit tests. This will be checked and verified during code review. Once the Pull Request is opened, our CI server will run the unit test suite and run a code linter to verify that the code follows the coding guidelines.
 
 If you want to run the unit tests and linter on your machine, run the following commands:
 

CONTRIBUTORS.md

@@ -3,6 +3,8 @@ cccatalog-api contributors (sorted alphabetically by last name)
 
 * **[Liza Daley](https://github.com/lizadaly)**
   * Built CC Search prototype, bits of which live on in this repository to this day
+* **[Princewill Onyenanu](https://github.com/madewithkode)**
+  * Implemented Elasticsearch `image` index availability check on `/healthcheck` view
 * **[Alden Page](https://github.com/aldenstpage)**
   * Author and maintainer of current implementation
 * **[Paulo Rosário](https://github.com/paulofilip3)**

cccatalog-api/cccatalog/api/views/site_views.py

@@ -7,7 +7,7 @@
 from rest_framework.reverse import reverse
 from rest_framework.views import APIView
 from rest_framework import serializers
-from cccatalog.api.controllers.search_controller import get_providers
+from cccatalog.api.controllers.search_controller import get_providers, es
 from cccatalog.api.serializers.oauth2_serializers import\
     OAuth2RegistrationSerializer, OAuth2RegistrationSuccessful, OAuth2KeyInfo
 from drf_yasg.utils import swagger_auto_schema
@@ -17,17 +17,22 @@
 from cccatalog.api.utils.oauth2_helper import get_token_info
 from cccatalog.settings import THUMBNAIL_PROXY_URL, THUMBNAIL_WIDTH_PX
 from django.core.cache import cache
+from django.views.decorators.cache import cache_page
+from django.utils.decorators import method_decorator
 from django.http import HttpResponse
 
 IDENTIFIER = 'provider_identifier'
 NAME = 'provider_name'
 FILTER = 'filter_content'
 URL = 'domain_name'
+HEALTH_CACHE_TTL = 10
 
 
+@method_decorator(cache_page(10), name='get')
 class HealthCheck(APIView):
     """
-    Returns a `200 OK` response if the server is running.
+    Returns a `200 OK` response if the server is running and `image` 
+    index exists and a `500 Internal Server Error` if either of the condition fails.
 
     This endpoint is used in production to ensure that the server should receive
     traffic. If no response is provided, the server is deregistered from the
@@ -36,8 +41,14 @@ class HealthCheck(APIView):
     swagger_schema = None
 
     def get(self, request, format=None):
-        return Response('', status=200)
-
+        es_conn = es
+        image_index_exists = es_conn.indices.exists(index=["image"])
+        if image_index_exists:
+            return Response('', status=200)
+        else:
+            log.error('The health check failed because the cluster image index is either unhealthy or non-existent')
+            return Response('', status=500)
+
 
 class AboutImageResponse(serializers.Serializer):
     """ The full image search response. """

cccatalog-api/cccatalog/settings.py

@@ -155,6 +155,7 @@
     }
 }
 
+
 # Produce CC-hosted thumbnails dynamically through a proxy.
 PROXY_THUMBS = bool(os.environ.get('PROXY_THUMBS', True))
 THUMBNAIL_PROXY_URL = os.environ.get(

cccatalog-api/cccatalog/urls.py

@@ -29,6 +29,7 @@
 from drf_yasg import openapi
 import rest_framework.permissions
 
+
 description = """
 *This is the documentation for version 1.0 of the Creative Commons API.
 Visit https://api.creativecommons.engineering/v0/ to view the legacy