Add basic in-memory caching

elastic · Nov 9, 2023 · 57245aa · 57245aa
1 parent 68f4d4b
commit 57245aa
Show file tree

Hide file tree

Showing 3 changed files with 30 additions and 15 deletions.
diff --git a/x-pack/plugins/fleet/server/routes/agent/handlers.ts b/x-pack/plugins/fleet/server/routes/agent/handlers.ts
@@ -357,14 +357,7 @@ export const getAvailableVersionsHandler: RequestHandler = async (context, reque
     const availableVersions = await AgentService.getAvailableVersions();
     const body: GetAvailableVersionsResponse = { items: availableVersions };
 
-    // This endpoint is cached to avoid reaching out to disk and the live product versions API
-    // for every single request
-    const CACHE_DURATION_SECONDS = 60 * 60 * 2; // 2 hours
-
-    return response.ok({
-      body,
-      headers: { 'cache-control': `max-age=${CACHE_DURATION_SECONDS}` },
-    });
+    return response.ok({ body });
   } catch (error) {
     return defaultFleetErrorHandler({ error, response });
   }

diff --git a/x-pack/plugins/fleet/server/services/agents/versions.test.ts b/x-pack/plugins/fleet/server/services/agents/versions.test.ts
@@ -46,7 +46,7 @@ describe('getAvailableVersions', () => {
     mockedReadFile.mockResolvedValue(`["8.1.0", "8.0.0", "7.17.0", "7.16.0"]`);
     mockedFetch.mockResolvedValueOnce(emptyResponse);
 
-    const res = await getAvailableVersions({ includeCurrentVersion: true });
+    const res = await getAvailableVersions({ includeCurrentVersion: true, ignoreCache: true });
 
     expect(res).toEqual(['300.0.0', '8.1.0', '8.0.0', '7.17.0']);
   });
@@ -56,7 +56,7 @@ describe('getAvailableVersions', () => {
     mockedReadFile.mockResolvedValue(`["8.1.0", "8.0.0", "7.17.0", "7.16.0"]`);
     mockedFetch.mockResolvedValueOnce(emptyResponse);
 
-    const res = await getAvailableVersions({ includeCurrentVersion: true });
+    const res = await getAvailableVersions({ includeCurrentVersion: true, ignoreCache: true });
     expect(res).toEqual(['300.0.0-SNAPSHOT', '8.1.0', '8.0.0', '7.17.0']);
   });
 
@@ -70,7 +70,7 @@ describe('getAvailableVersions', () => {
     mockedReadFile.mockResolvedValue(`["8.1.0", "8.0.0", "7.17.0", "7.16.0"]`);
     mockedFetch.mockResolvedValueOnce(emptyResponse);
 
-    const res = await getAvailableVersions();
+    const res = await getAvailableVersions({ ignoreCache: true });
 
     expect(res).toEqual(['8.1.0', '8.0.0', '7.17.0']);
   });
@@ -80,7 +80,7 @@ describe('getAvailableVersions', () => {
     mockedReadFile.mockResolvedValue(`["8.1.0", "8.0.0", "7.17.0", "7.16.0"]`);
     mockedFetch.mockResolvedValueOnce(emptyResponse);
 
-    const res = await getAvailableVersions({ includeCurrentVersion: false });
+    const res = await getAvailableVersions({ includeCurrentVersion: false, ignoreCache: true });
 
     expect(res).toEqual(['8.1.0', '8.0.0', '7.17.0']);
   });
@@ -95,7 +95,7 @@ describe('getAvailableVersions', () => {
     mockedReadFile.mockRejectedValue({ code: 'ENOENT' });
     mockedFetch.mockResolvedValueOnce(emptyResponse);
 
-    const res = await getAvailableVersions();
+    const res = await getAvailableVersions({ ignoreCache: true });
 
     expect(res).toEqual(['300.0.0']);
   });
@@ -126,7 +126,7 @@ describe('getAvailableVersions', () => {
       ),
     } as any);
 
-    const res = await getAvailableVersions();
+    const res = await getAvailableVersions({ ignoreCache: true });
 
     // Should sort, uniquify and filter out versions < 7.17
     expect(res).toEqual(['8.10.0', '8.9.2', '8.1.0', '8.0.0', '7.17.0']);

diff --git a/x-pack/plugins/fleet/server/services/agents/versions.ts b/x-pack/plugins/fleet/server/services/agents/versions.ts
@@ -25,6 +25,11 @@ const AGENT_VERSION_BUILD_FILE = 'x-pack/plugins/fleet/target/agent_versions_lis
 // Endpoint maintained by the web-team and hosted on the elastic website
 const PRODUCT_VERSIONS_URL = 'https://www.elastic.co/api/product_versions';
 
+// Cache available versions in memory for 1 hour
+const CACHE_DURATION = 1000 * 60 * 60;
+let CACHED_AVAILABLE_VERSIONS: string[] | undefined;
+let LAST_FETCHED: number | undefined;
+
 export const getLatestAvailableVersion = async (
   includeCurrentVersion?: boolean
 ): Promise<string> => {
@@ -35,12 +40,26 @@ export const getLatestAvailableVersion = async (
 
 export const getAvailableVersions = async ({
   includeCurrentVersion,
+  ignoreCache = false, // This is only here to allow us to ignore the cache in tests
 }: {
   includeCurrentVersion?: boolean;
+  ignoreCache?: boolean;
 } = {}): Promise<string[]> => {
   const logger = appContextService.getLogger();
-  const config = appContextService.getConfig();
 
+  if (LAST_FETCHED && !ignoreCache) {
+    const msSinceLastFetched = Date.now() - (LAST_FETCHED || 0);
+
+    if (msSinceLastFetched < CACHE_DURATION && CACHED_AVAILABLE_VERSIONS !== undefined) {
+      logger.debug(`Cache is valid, returning cached available versions`);
+
+      return CACHED_AVAILABLE_VERSIONS;
+    }
+
+    logger.debug('Cache has expired, fetching available versions from disk + API');
+  }
+
+  const config = appContextService.getConfig();
   const kibanaVersion = appContextService.getKibanaVersion();
 
   let availableVersions: string[] = [];
@@ -81,6 +100,9 @@ export const getAvailableVersions = async ({
     availableVersions = [kibanaVersion];
   }
 
+  CACHED_AVAILABLE_VERSIONS = availableVersions;
+  LAST_FETCHED = Date.now();
+
   return availableVersions;
 };