introduce a new sharedKey option

fixes #6

README.md

@@ -21,6 +21,9 @@ sensible defaults.
 : `key`
 An optional key that is added to the automatic cache key.
 
+: `sharedKey`
+An additional key that is stable over multiple jobs.
+
 : `working-directory`
 The working directory the action operates in, is case the cargo project is not
 located in the repo root.

action.yml

@@ -5,6 +5,9 @@ inputs:
   key:
     description: "An additional key for the cache"
     required: false
+  sharedKey:
+    description: "An additional cache key that is stable over multiple jobs"
+    required: false
   working-directory:
     description: "The working directory this action should operate in"
     required: false

src/common.ts

@@ -49,14 +49,19 @@ export async function getCacheConfig(): Promise<CacheConfig> {
 
   let key = `v0-rust-`;
 
-  let inputKey = core.getInput("key");
-  if (inputKey) {
-    key += `${inputKey}-`;
-  }
+  const sharedKey = core.getInput("sharedKey");
+  if (sharedKey) {
+    key += `${sharedKey}-`;
+  } else {
+    const inputKey = core.getInput("key");
+    if (inputKey) {
+      key += `${inputKey}-`;
+    }
 
-  const job = process.env.GITHUB_JOB;
-  if (job) {
-    key += `${job}-`;
+    const job = process.env.GITHUB_JOB;
+    if (job) {
+      key += `${job}-`;
+    }
   }
 
   key += await getRustKey();