CMR-9519 Fixing KMS replacement of cache when KMS API is down. (#1983)

common-app-lib/src/cmr/common_app/services/kms_fetcher.clj

@@ -13,20 +13,17 @@
                      {...}]}
          :providers [...]}"
   (:require
-    [clojure.string :as str]
-    [cmr.common-app.services.kms-lookup :as kms-lookup]
-    [cmr.common.cache :as cache]
-    [cmr.common.cache.deflating-cache :as deflating-cache]
-    [cmr.common.cache.fallback-cache :as fallback-cache]
-    [cmr.common.cache.single-thread-lookup-cache :as stl-cache]
-    [cmr.common.config :refer [defconfig]]
-    [cmr.common.jobs :refer [def-stateful-job]]
-    [cmr.common.log :as log :refer [debug info warn error]]
-    [cmr.common.services.errors :as errors]
-    [cmr.common.util :as util]
-    [cmr.redis-utils.redis-cache :as redis-cache]
-    [cmr.transmit.cache.consistent-cache :as consistent-cache]
-    [cmr.transmit.kms :as kms]))
+   [cmr.common-app.services.kms-lookup :as kms-lookup]
+   [cmr.common.cache :as cache]
+   [cmr.common.cache.deflating-cache :as deflating-cache]
+   [cmr.common.cache.fallback-cache :as fallback-cache]
+   [cmr.common.cache.single-thread-lookup-cache :as stl-cache]
+   [cmr.common.config :refer [defconfig]]
+   [cmr.common.jobs :refer [def-stateful-job]]
+   [cmr.common.log :as log :refer [debug info warn error]]
+   [cmr.redis-utils.redis-cache :as redis-cache]
+   [cmr.transmit.cache.consistent-cache :as consistent-cache]
+   [cmr.transmit.kms :as kms]))
 
 (def nested-fields-mappings
   "Mapping from field name to the list of subfield names in order from the top of the hierarchy to
@@ -78,10 +75,16 @@
   "Calls GCMD KMS endpoints to retrieve the keywords. Response is a map structured in the same way
   as used in the KMS cache."
   [context]
-  (kms-lookup/create-kms-index
-   (into {}
-         (for [keyword-scheme (keys kms/keyword-scheme->field-names)]
-           [keyword-scheme (kms/get-keywords-for-keyword-scheme context keyword-scheme)]))))
+  (let [kms-cache (cache/context->cache context kms-cache-key)
+        kms-cache-value (cache/get-value kms-cache kms-cache-key)]
+    (kms-lookup/create-kms-index
+     (into {}
+           (for [keyword-scheme (keys kms/keyword-scheme->field-names)]
+             ;; if the keyword-scheme-value is nil that means we could not get the KMS keywords
+             ;; in this case use the cached value value instead so that we dont wipe out the cache.
+             (if-let [keyword-scheme-value (kms/get-keywords-for-keyword-scheme context keyword-scheme)]
+               [keyword-scheme keyword-scheme-value]
+               [keyword-scheme (get kms-cache-value keyword-scheme)]))))))
 
 (defn get-kms-index
   "Retrieves the GCMD keywords map from the cache."

common-app-lib/test/cmr/common_app/services/kms_fetcher_test.clj

@@ -0,0 +1,28 @@
+(ns cmr.common-app.services.kms-fetcher-test
+  (:require
+   [clojure.test :refer :all]
+   [cmr.common.cache :as cache]
+   [cmr.common-app.services.kms-fetcher :as fetcher]
+   [cmr.indexer.system :as idx-sys]
+   [cmr.transmit.kms :as trans-kms]))
+
+(deftest validate-getting-kms-keywords-test
+  (let [context {:system (idx-sys/create-system)}
+        kms-cache (cache/context->cache context fetcher/kms-cache-key)
+        _  (#'fetcher/refresh-kms-cache context)
+        kms-map (cache/get-value kms-cache fetcher/kms-cache-key)]
+
+    (testing "Testing that KMS keywords such as projects exist after normal loading."
+      (is (some? (:projects kms-map))))
+
+    (testing "Test KMS keywords API returning nil for testing purposes."
+      (let [context (assoc context :testing-for-nil-keyword-scheme-value true)]
+        (is (nil? (trans-kms/get-keywords-for-keyword-scheme context :projects)))))
+
+    ;; Test to make sure that if KMS keywords API returns nil for a keyword after 
+    ;; parsing, (KMS API is down) that previous cache value is used, so that we don't
+    ;; wipe out the KMS keyword values in the cache.
+    (testing "Makes sure that KMS keywords are not wiped out."
+      (let [context (assoc context :testing-for-nil-keyword-scheme-value true)]
+        (#'fetcher/refresh-kms-cache context)
+        (is (some? (:projects (cache/get-value kms-cache fetcher/kms-cache-key))))))))

transmit-lib/src/cmr/transmit/kms.clj

@@ -205,7 +205,6 @@
    subregion-4, but KMS has already implemented it. This allows the CMR to use either the subregion-3
    or subregion-4 KMS output."
   [keyword-scheme keyword-entries]
-  (def keyword-entries keyword-entries)
   (if (= keyword-scheme :spatial-keywords)
     (map #(dissoc % :subregion-4) keyword-entries)
     keyword-entries))
@@ -301,9 +300,10 @@
    :category \"Earth Observation Satellites\" :basis \"Space-based Platforms\"} ..."
   [context keyword-scheme]
   {:pre (some? (keyword-scheme keyword-scheme->field-names))}
-  (when-not (= keyword-scheme :spatial-keywords-old)
+  (when-not (or (= keyword-scheme :spatial-keywords-old)
+                (:testing-for-nil-keyword-scheme-value context))
     (let [keywords
-           (parse-entries-from-csv keyword-scheme (get-by-keyword-scheme context keyword-scheme))]
+          (parse-entries-from-csv keyword-scheme (get-by-keyword-scheme context keyword-scheme))]
       (info (format "Found %s keywords for %s" (count (keys keywords)) (name keyword-scheme)))
       keywords)))