Adds a configuration option to fact retrievers to define lifecycle for facts the retriever persists. Possible values are either 'items-to-live' or 'time-to-live'. The former will only n number of items in to the database for each fact per entity. The latter will remove all facts that are older than the TTL value.

Possible values:
* { itl: 5 } // Deletes all facts for the retriever/entity pair, apart from the last five
* { ttl: 1209600000 } // (2 weeks) Deletes all facts older than 2 weeks for the retriever/entity pair
* { ttl: { weeks: 2 } } // Deletes all facts older than 2 weeks for the retriever/entity pair

Signed-off-by: Jussi Hallila <jussi@hallila.com>

plugins/tech-insights-node/src/facts.ts

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { DateTime } from 'luxon';
+import { DateTime, DurationLike } from 'luxon';
 import { Config } from '@backstage/config';
 import { PluginEndpointDiscovery } from '@backstage/backend-common';
 import { Logger } from 'winston';
@@ -190,6 +190,36 @@ export interface FactRetriever {
     | Record<string, string | symbol | (string | symbol)[]>;
 }
 
+/**
+ * @public
+ *
+ * A Luxon duration like object for time to live value
+ *
+ * @example
+ * \{ ttl: 1209600000 \}
+ * \{ ttl: \{ weeks: 4 \} \}
+ *
+ **/
+export type TTL = { ttl: DurationLike };
+
+/**
+ * @public
+ *
+ * A number for items to live value
+ *
+ * @example
+ * \{ itl: 10 \}
+ *
+ **/
+export type ITL = { itl: number };
+
+/**
+ * @public
+ *
+ * A fact lifecycle definition. Determines which strategy to use to purge expired facts from the database.
+ */
+export type FactLifecycle = TTL | ITL;
+
 /**
  * @public
  *
@@ -216,4 +246,11 @@ export type FactRetrieverRegistration = {
    *
    */
   cadence?: string;
+
+  /**
+   * Fact lifecycle definition
+   *
+   * If defined this value will be used to determine expired items which will deleted when this fact retriever is run
+   */
+  lifecycle?: FactLifecycle;
 };

plugins/tech-insights-node/src/persistence.ts

@@ -18,6 +18,7 @@ import {
   TechInsightFact,
   FlatTechInsightFact,
   FactSchemaDefinition,
+  FactLifecycle,
 } from './facts';
 import { DateTime } from 'luxon';
 
@@ -35,8 +36,13 @@ export interface TechInsightsStore {
    *
    * @param id - Unique identifier of the fact retriever these facts relate to
    * @param facts - A collection of TechInsightFacts
+   * @param lifecycle - (Optional) Fact lifecycle object indicating the expiration logic for these items
    */
-  insertFacts(id: string, facts: TechInsightFact[]): Promise<void>;
+  insertFacts(
+    id: string,
+    facts: TechInsightFact[],
+    lifecycle?: FactLifecycle,
+  ): Promise<void>;
 
   /**
    * @param ids - A collection of fact row identifiers