From 38276bbbff6b32fe7e29ebcb8c318de6316c09b4 Mon Sep 17 00:00:00 2001
From: Sebastian Malton <sebastian@malton.name>
Date: Wed, 20 Oct 2021 08:50:52 -0400
Subject: [PATCH] Update helm cache if files have been modified (#3973)

---
 src/common/utils/sort-compare.ts    |   2 +-
 src/main/helm/helm-chart-manager.ts | 104 ++++++++++++++++++----------
 2 files changed, 67 insertions(+), 39 deletions(-)

diff --git a/src/common/utils/sort-compare.ts b/src/common/utils/sort-compare.ts
index 799c47f957..7167761151 100644
--- a/src/common/utils/sort-compare.ts
+++ b/src/common/utils/sort-compare.ts
@@ -111,5 +111,5 @@ export function sortCharts(charts: RawHelmChart[]) {
 
   return chartsWithVersion
     .sort(sortCompareChartVersions)
-    .map(chart => (delete chart.__version, chart));
+    .map(chart => (delete chart.__version, chart as RawHelmChart));
 }
diff --git a/src/main/helm/helm-chart-manager.ts b/src/main/helm/helm-chart-manager.ts
index e99554dcd0..b7afb6ff3d 100644
--- a/src/main/helm/helm-chart-manager.ts
+++ b/src/main/helm/helm-chart-manager.ts
@@ -24,10 +24,15 @@ import v8 from "v8";
 import * as yaml from "js-yaml";
 import type { HelmRepo } from "./helm-repo-manager";
 import logger from "../logger";
-import { promiseExec } from "../promise-exec";
+import { promiseExecFile } from "../promise-exec";
 import { helmCli } from "./helm-cli";
 import type { RepoHelmChartList } from "../../common/k8s-api/endpoints/helm-charts.api";
-import { sortCharts } from "../../common/utils";
+import { iter, sortCharts } from "../../common/utils";
+
+interface ChartCacheEntry {
+  data: Buffer,
+  mtimeMs: number,
+}
 
 export interface HelmCacheFile {
   apiVersion: string;
@@ -35,7 +40,7 @@ export interface HelmCacheFile {
 }
 
 export class HelmChartManager {
-  static #cache = new Map<string, Buffer>();
+  static #cache = new Map<string, ChartCacheEntry>();
 
   private constructor(protected repo: HelmRepo) {}
 
@@ -59,16 +64,17 @@ export class HelmChartManager {
     }
   }
 
-  private async executeCommand(action: string, name: string, version?: string) {
+  private async executeCommand(args: string[], name: string, version?: string) {
     const helm = await helmCli.binaryPath();
-    const cmd = [`"${helm}" ${action} ${this.repo.name}/${name}`];
+
+    args.push(`${this.repo.name}/${name}`);
 
     if (version) {
-      cmd.push("--version", version);
+      args.push("--version", version);
     }
 
     try {
-      const { stdout } = await promiseExec(cmd.join(" "));
+      const { stdout } = await promiseExecFile(helm, args);
 
       return stdout;
     } catch (error) {
@@ -77,47 +83,69 @@ export class HelmChartManager {
   }
 
   public async getReadme(name: string, version?: string) {
-    return this.executeCommand("show readme", name, version);
+    return this.executeCommand(["show", "readme"], name, version);
   }
 
   public async getValues(name: string, version?: string) {
-    return this.executeCommand("show values", name, version);
+    return this.executeCommand(["show", "values"], name, version);
+  }
+
+  protected async updateYamlCache() {
+    const cacheFile = await fs.promises.readFile(this.repo.cacheFilePath, "utf-8");
+    const cacheFileStats = await fs.promises.stat(this.repo.cacheFilePath);
+    const data = yaml.load(cacheFile) as string | number | HelmCacheFile;
+
+    if (!data || typeof data !== "object" || typeof data.entries !== "object") {
+      throw Object.assign(new TypeError("Helm Cache file does not parse correctly"), { file: this.repo.cacheFilePath, data });
+    }
+
+    const normalized = normalizeHelmCharts(this.repo.name, data.entries);
+
+    HelmChartManager.#cache.set(this.repo.name, {
+      data: v8.serialize(normalized),
+      mtimeMs: cacheFileStats.mtimeMs,
+    });
   }
 
   protected async cachedYaml(): Promise<RepoHelmChartList> {
     if (!HelmChartManager.#cache.has(this.repo.name)) {
-      const cacheFile = await fs.promises.readFile(this.repo.cacheFilePath, "utf-8");
-      const data = yaml.load(cacheFile) as string | number | HelmCacheFile;
+      await this.updateYamlCache();
+    } else {
+      const newStats = await fs.promises.stat(this.repo.cacheFilePath);
+      const cacheEntry = HelmChartManager.#cache.get(this.repo.name);
 
-      if (typeof data !== "object" || !data) {
-        return {};
+      if (cacheEntry.mtimeMs < newStats.mtimeMs) {
+        await this.updateYamlCache();
       }
-
-      /**
-       * Do some initial preprocessing on the data, so as to avoid needing to do it later
-       * 1. Set the repo name
-       * 2. Normalize the created date
-       * 3. Filter out deprecated items
-       */
-
-      const normalized = Object.fromEntries(
-        Object.entries(data.entries)
-          .map(([name, charts]) => [
-            name,
-            sortCharts(
-              charts.map(chart => ({
-                ...chart,
-                created: Date.parse(chart.created).toString(),
-                repo: this.repo.name,
-              })),
-            ),
-          ] as const)
-          .filter(([, charts]) => !charts.every(chart => chart.deprecated))
-      );
-
-      HelmChartManager.#cache.set(this.repo.name, v8.serialize(normalized));
     }
 
-    return v8.deserialize(HelmChartManager.#cache.get(this.repo.name));
+    return v8.deserialize(HelmChartManager.#cache.get(this.repo.name).data);
   }
 }
+
+/**
+ * Do some initial preprocessing on the data, so as to avoid needing to do it later
+ * 1. Set the repo name
+ * 2. Normalize the created date
+ * 3. Filter out charts that only have deprecated entries
+ */
+function normalizeHelmCharts(repoName: string, entries: RepoHelmChartList): RepoHelmChartList {
+  return Object.fromEntries(
+    iter.filter(
+      iter.map(
+        Object.entries(entries),
+        ([name, charts]) => [
+          name,
+          sortCharts(
+            charts.map(chart => ({
+              ...chart,
+              created: Date.parse(chart.created).toString(),
+              repo: repoName,
+            })),
+          ),
+        ] as const
+      ),
+      ([, charts]) => !charts.every(chart => chart.deprecated),
+    )
+  );
+}