From 4fee8f59e33b8928b3cb8dbfddf2286948b7ed55 Mon Sep 17 00:00:00 2001
From: Milos Protic <protic023@gmail.com>
Date: Mon, 16 May 2022 15:13:57 +0200
Subject: [PATCH] fixed tech-insights API endpoint to return the proper latest
 value

Signed-off-by: Milos Protic <protic023@gmail.com>
---
 .changeset/beige-apricots-enjoy.md            |  5 ++
 .../persistence/TechInsightsDatabase.test.ts  | 77 +++++++++++++++++++
 .../persistence/TechInsightsDatabase.ts       |  8 +-
 3 files changed, 87 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/beige-apricots-enjoy.md

diff --git a/.changeset/beige-apricots-enjoy.md b/.changeset/beige-apricots-enjoy.md
new file mode 100644
index 0000000000..bd1f932454
--- /dev/null
+++ b/.changeset/beige-apricots-enjoy.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-tech-insights-backend': patch
+---
+
+Updated tech-insights fetch/latest endpoint to return the actual latest row based on the timestamp
diff --git a/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.test.ts b/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.test.ts
index c69432d070..e7e8819c66 100644
--- a/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.test.ts
+++ b/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.test.ts
@@ -115,6 +115,56 @@ const additionalFacts = [
   },
 ];
 
+const sameFactsDiffDateSchema = {
+  id: 'same-fact-diff-date-test',
+  version: '0.0.1-test',
+  entityFilter: JSON.stringify([{ kind: 'service' }]),
+  schema: JSON.stringify({
+    testStringFact: {
+      type: 'string',
+      description: 'Test fact with a string type',
+    },
+  }),
+};
+
+const sameFactsDiffDateNow = DateTime.now().toISO();
+const sameFactsDiffDateNearFuture = DateTime.now()
+  .plus(Duration.fromMillis(555))
+  .toISO();
+const sameFactsDiffDateFuture = DateTime.now()
+  .plus(Duration.fromMillis(1000))
+  .toISO();
+
+const multipleSameFacts = [
+  {
+    timestamp: sameFactsDiffDateNow,
+    id: sameFactsDiffDateSchema.id,
+    version: '0.0.1-test',
+    entity: 'a:a/a',
+    facts: JSON.stringify({
+      testNumberFact: 1,
+    }),
+  },
+  {
+    timestamp: sameFactsDiffDateNearFuture,
+    id: sameFactsDiffDateSchema.id,
+    version: '0.0.1-test',
+    entity: 'a:a/a',
+    facts: JSON.stringify({
+      testNumberFact: 2,
+    }),
+  },
+  {
+    timestamp: sameFactsDiffDateFuture,
+    id: 'multiple-same-facts',
+    version: '0.0.1-test',
+    entity: 'a:a/a',
+    facts: JSON.stringify({
+      testNumberFact: 3,
+    }),
+  },
+];
+
 describe('Tech Insights database', () => {
   const databases = TestDatabases.create();
   let store: TechInsightsStore;
@@ -215,6 +265,33 @@ describe('Tech Insights database', () => {
     expect(returnedFact['test-fact']).toMatchObject(baseAssertionFact);
   });
 
+  it('should return latest fact with multiple entries', async () => {
+    await testDbClient.batchInsert('fact_schemas', [sameFactsDiffDateSchema]);
+    await testDbClient.batchInsert(
+      'facts',
+      multipleSameFacts.map(fact => ({
+        ...fact,
+        id: sameFactsDiffDateSchema.id,
+      })),
+    );
+
+    const returnedFacts = await store.getLatestFactsByIds(
+      ['test-fact', sameFactsDiffDateSchema.id],
+      'a:a/a',
+    );
+
+    expect(returnedFacts['test-fact']).toMatchObject({
+      ...baseAssertionFact,
+    });
+
+    expect(returnedFacts[sameFactsDiffDateSchema.id]).toMatchObject({
+      ...baseAssertionFact,
+      id: sameFactsDiffDateSchema.id,
+      timestamp: DateTime.fromISO(sameFactsDiffDateFuture),
+      facts: { testNumberFact: 3 },
+    });
+  });
+
   it('should return latest facts for multiple ids', async () => {
     await testDbClient.batchInsert('fact_schemas', [secondSchema]);
     await testDbClient.batchInsert(
diff --git a/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.ts b/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.ts
index 3507e280a1..c6751e864a 100644
--- a/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.ts
+++ b/plugins/tech-insights-backend/src/service/persistence/TechInsightsDatabase.ts
@@ -131,14 +131,16 @@ export class TechInsightsDatabase implements TechInsightsStore {
       .and.whereIn('id', ids)
       .join(
         this.db('facts')
-          .max('timestamp')
+          .max('timestamp as maxTimestamp')
           .column('id as subId')
           .where({ entity: entityTriplet })
           .and.whereIn('id', ids)
           .groupBy('id')
           .as('subQ'),
-        'facts.id',
-        'subQ.subId',
+        {
+          'facts.id': 'subQ.subId',
+          'facts.timestamp': 'subQ.maxTimestamp',
+        },
       );
     return this.dbFactRowsToTechInsightFacts(results);
   }