Add bare-bones dependency caching functions

src/dependency-caching.ts

@@ -0,0 +1,145 @@
+import * as os from "os";
+import { join } from "path";
+
+import * as actionsCache from "@actions/cache";
+import * as glob from "@actions/glob";
+
+import { getTotalCacheSize } from "./caching-utils";
+import { Config } from "./config-utils";
+import { Language } from "./languages";
+import { Logger } from "./logging";
+import { getRequiredEnvParam } from "./util";
+
+interface CacheConfig {
+  paths: string[];
+  hash: string[];
+}
+
+const CODEQL_DEPENDENCY_CACHE_PREFIX = "codeql-dependencies";
+const CODEQL_DEPENDENCY_CACHE_VERSION = 1;
+
+const CODEQL_DEFAULT_CACHE_CONFIG: { [language: string]: CacheConfig } = {
+  java: {
+    paths: [
+      // Maven
+      join(os.homedir(), ".m2", "repository"),
+      // Gradle
+      join(os.homedir(), ".gradle", "caches"),
+    ],
+    hash: [
+      // Maven
+      "**/pom.xml",
+      // Gradle
+      "**/*.gradle*",
+      "**/gradle-wrapper.properties",
+      "buildSrc/**/Versions.kt",
+      "buildSrc/**/Dependencies.kt",
+      "gradle/*.versions.toml",
+      "**/versions.properties",
+    ],
+  },
+};
+
+/**
+ * Attempts to restore dependency caches for the languages being analyzed.
+ *
+ * @param languages The languages being analyzed.
+ * @param logger A logger to record some informational messages to.
+ * @returns A list of languages for which dependency caches were restored.
+ */
+export async function downloadDependencyCaches(
+  languages: Language[],
+  logger: Logger,
+): Promise<Language[]> {
+  const restoredCaches: Language[] = [];
+
+  for (const language of languages) {
+    const cacheConfig = CODEQL_DEFAULT_CACHE_CONFIG[language];
+
+    if (cacheConfig === undefined) {
+      logger.info(
+        `Skipping download of dependency cache for ${language} as we have no caching configuration for it.`,
+      );
+      continue;
+    }
+
+    const primaryKey = await cacheKey(language, cacheConfig);
+    const restoreKeys: string[] = [await cachePrefix(language)];
+
+    logger.info(
+      `Downloading cache for ${language} with key ${primaryKey} and restore keys ${restoreKeys.join(
+        ", ",
+      )}`,
+    );
+
+    const hitKey = await actionsCache.restoreCache(
+      cacheConfig.paths,
+      primaryKey,
+      restoreKeys,
+    );
+
+    if (hitKey !== undefined) {
+      logger.info(`Cache hit on key ${hitKey} for ${language}.`);
+      restoredCaches.push(language);
+    }
+  }
+
+  return restoredCaches;
+}
+
+/**
+ * Attempts to store caches for the languages that were analyzed.
+ *
+ * @param config The configuration for this workflow.
+ * @param logger A logger to record some informational messages to.
+ */
+export async function uploadDependencyCaches(config: Config, logger: Logger) {
+  for (const language of config.languages) {
+    const cacheConfig = CODEQL_DEFAULT_CACHE_CONFIG[language];
+
+    if (cacheConfig === undefined) {
+      logger.info(
+        `Skipping upload of dependency cache for ${language} as we have no caching configuration for it.`,
+      );
+      continue;
+    }
+
+    const globber = await glob.create(cacheConfig.hash.join("\n"));
+    const size = await getTotalCacheSize(await globber.glob(), logger);
+
+    const key = await cacheKey(language, cacheConfig);
+
+    logger.info(
+      `Uploading cache of size ${size} for ${language} with key ${key}`,
+    );
+
+    await actionsCache.saveCache(cacheConfig.paths, key);
+  }
+}
+
+/**
+ * Computes a cache key for the specified language.
+ *
+ * @param language The language being analyzed.
+ * @param cacheConfig The cache configuration for the language.
+ * @returns A cache key capturing information about the project(s) being analyzed in the specified language.
+ */
+async function cacheKey(
+  language: Language,
+  cacheConfig: CacheConfig,
+): Promise<string> {
+  const hash = await glob.hashFiles(cacheConfig.hash.join("\n"));
+  return `${await cachePrefix(language)}${hash}`;
+}
+
+/**
+ * Constructs a prefix for the cache key, comprised of a CodeQL-specific prefix, a version number that
+ * can be changed to invalidate old caches, the runner's operating system, and the specified language name.
+ *
+ * @param language The language being analyzed.
+ * @returns The prefix that identifies what a cache is for.
+ */
+async function cachePrefix(language: Language): Promise<string> {
+  const runnerOs = getRequiredEnvParam("RUNNER_OS");
+  return `${CODEQL_DEPENDENCY_CACHE_PREFIX}-${CODEQL_DEPENDENCY_CACHE_VERSION}-${runnerOs}-${language}-`;
+}