Validate event type during restore

src/constants.ts

@@ -12,3 +12,9 @@ export namespace State {
     export const CacheKey = "CACHE_KEY";
     export const CacheResult = "CACHE_RESULT";
 }
+
+export namespace Events {
+    export const Key = "GITHUB_EVENT_NAME";
+    export const Push = "push";
+    export const PullRequest = "pull_request";
+}

src/restore.ts

@@ -11,6 +11,12 @@ import * as utils from "./utils/actionUtils";
 async function run() {
     try {
         // Validate inputs, this can cause task failure
+        if (!utils.isValidEvent()) {
+            core.setFailed(
+                `Event Validation Error: The event type ${process.env["GITHUB_EVENT_NAME"]} is not supported. Only \`push\` and \`pull_request\` events are supported at this time.`
+            );
+        }
+
         let cachePath = utils.resolvePath(
             core.getInput(Inputs.Path, { required: true })
         );

src/utils/actionUtils.ts

@@ -5,7 +5,7 @@ import * as os from "os";
 import * as path from "path";
 import * as uuidV4 from "uuid/v4";
 
-import { Outputs, State } from "../constants";
+import { Events, Outputs, State } from "../constants";
 import { ArtifactCacheEntry } from "../contracts";
 
 // From https://github.com/actions/toolkit/blob/master/packages/tool-cache/src/tool-cache.ts#L23
@@ -84,3 +84,11 @@ export function resolvePath(filePath: string): string {
 
     return path.resolve(filePath);
 }
+
+// Currently the cache token is only authorized for push and pull_request events
+// All other events will fail when reading and saving the cache
+// See GitHub Context https://help.github.com/actions/automating-your-workflow-with-github-actions/contexts-and-expression-syntax-for-github-actions#github-context
+export function isValidEvent(): boolean {
+    const githubEvent = process.env[Events.Key] || "";
+    return githubEvent === Events.Push || githubEvent === Events.PullRequest;
+}