cloud: Add kcidb_cache_redirect function

cloud

@@ -1474,6 +1474,17 @@ function cloud_functions_deploy() {
                           --max-instances=1 \
                           --timeout 540
 
+    cloud_function_deploy "$project" "${prefix}cache_redirect" \
+                          "$source" \
+                          --entry-point kcidb_cache_redirect \
+                          --env-vars-file "$env_yaml_file" \
+                          --runtime python37 \
+                          --trigger-http \
+                          --allow-unauthenticated \
+                          --memory 256MB \
+                          --max-instances=1 \
+                          --timeout 540
+
     cloud_function_deploy "$project" "${prefix}load_queue" \
                           "$source" \
                           --entry-point kcidb_load_queue \

main.py

@@ -5,6 +5,8 @@
 import datetime
 import logging
 import smtplib
+from urllib.parse import unquote
+import functions_framework
 import kcidb
 
 # Name of the Google Cloud project we're deployed in
@@ -357,3 +359,48 @@ def kcidb_cache_urls(event, context):
     # Cache each URL
     for url in pubsub_message.splitlines():
         cache.store(url)
+
+
+@functions_framework.http
+def kcidb_cache_redirect(request):
+    """
+    Handle the cache redirection for incoming HTTP GET requests.
+
+    This function takes an HTTP request and processes it for
+    cache redirection. If the request is a GET request,
+    it extracts the URL from the request, checks if the URL exists
+    in the cache, and performs a redirect if necessary.
+
+    Args:
+        request (object): The HTTP request object.
+
+    Returns:
+        tuple: A tuple containing the response body, status code,
+        and headers epresenting the redirect response.
+    """
+    if request.method == 'GET':
+        url_to_fetch = unquote(request.query_string.decode("ascii"))
+        LOGGER.debug("URL %s", url_to_fetch)
+
+        if not url_to_fetch:
+            # If the URL is empty, return a 400 (Bad Request) error
+            response_body = "Put a valid URL to query from \
+                the caching system."
+            return (response_body, 400, {})
+
+        # Check if the URL is in the cache
+        cache_client = get_cache_client()
+        cache = cache_client.map(url_to_fetch)
+        if cache:
+            LOGGER.debug("Redirecting to the cache at %s", cache)
+            # Redirect to the cached URL if it exists
+            return ("", 302, {"Location": cache})
+
+        # If the URL is not in the cache or not provided,
+        # redirect to the original URL
+        LOGGER.debug("Redirecting to the origin at %s", url_to_fetch)
+        return ("", 302, {"Location": url_to_fetch})
+
+    # If the request method is not GET, return 405 (Method Not Allowed) error
+    response_body = "Method not allowed."
+    return (response_body, 405, {'Allow': 'GET'})

requirements.txt

@@ -6,6 +6,7 @@ google-cloud-firestore
 google-cloud-storage
 google-cloud-secret-manager
 psycopg2
+functions-framework
 importlib_metadata
 jsonschema[format]
 requests

setup.py

@@ -46,6 +46,7 @@
         "google-cloud-bigquery",
         "google-cloud-pubsub",
         "google-cloud-storage",
+        "functions-framework",
         "google-cloud-firestore",
         "google-cloud-secret-manager",
         "psycopg2",