Add CachingKind enum to control whether to restore or store caches

src/caching-utils.ts

@@ -1,5 +1,9 @@
+import * as core from "@actions/core";
+
+import { getOptionalInput, isDefaultSetup } from "./actions-util";
+import { EnvVar } from "./environment";
 import { Logger } from "./logging";
-import { tryGetFolderBytes } from "./util";
+import { isHostedRunner, tryGetFolderBytes } from "./util";
 
 /**
  * Returns the total size of all the specified paths.
@@ -16,3 +20,70 @@ export async function getTotalCacheSize(
   );
   return sizes.map((a) => a || 0).reduce((a, b) => a + b, 0);
 }
+
+/* Enumerates caching modes. */
+export enum CachingKind {
+  /** Do not restore or store any caches. */
+  None = "none",
+  /** Store caches, but do not restore any existing ones. */
+  Store = "store",
+  /** Restore existing caches, but do not store any new ones. */
+  Restore = "restore",
+  /** Restore existing caches, and store new ones. */
+  Full = "full",
+}
+
+/** Returns a value indicating whether new caches should be stored, based on `kind`. */
+export function shouldStoreCache(kind: CachingKind): boolean {
+  return kind === CachingKind.Full || kind === CachingKind.Store;
+}
+
+/** Returns a value indicating whether existing caches should be restored, based on `kind`. */
+export function shouldRestoreCache(kind: CachingKind): boolean {
+  return kind === CachingKind.Full || kind === CachingKind.Restore;
+}
+
+/**
+ * Parses the `upload` input into an `UploadKind`, converting unspecified and deprecated upload
+ * inputs appropriately.
+ */
+export function getCachingKind(input: string | undefined): CachingKind {
+  switch (input) {
+    case undefined:
+    case "none":
+    case "off":
+    case "false":
+      return CachingKind.None;
+    case "full":
+    case "on":
+    case "true":
+      return CachingKind.Full;
+    case "store":
+      return CachingKind.Store;
+    case "restore":
+      return CachingKind.Restore;
+    default:
+      core.warning(
+        `Unrecognized 'dependency-caching' input: ${input}. Defaulting to 'none'.`,
+      );
+      return CachingKind.None;
+  }
+}
+
+/** Determines whether dependency caching is enabled. */
+export function getDependencyCachingEnabled(): CachingKind {
+  // If the workflow specified something always respect that
+  const dependencyCaching =
+    getOptionalInput("dependency-caching") ||
+    process.env[EnvVar.DEPENDENCY_CACHING];
+  if (dependencyCaching !== undefined) return getCachingKind(dependencyCaching);
+
+  // On self-hosted runners which may have dependencies installed centrally, disable caching by default
+  if (!isHostedRunner()) return CachingKind.None;
+
+  // Disable in advanced workflows by default.
+  if (!isDefaultSetup()) return CachingKind.None;
+
+  // On hosted runners, enable dependency caching by default
+  return CachingKind.Full;
+}