remove expires arg and update readme

README.md

@@ -1,4 +1,27 @@
-# cached-docker-build-action
+# Cached Docker Build
 
+This Github Action stores and retrieves a Docker image from Github's cache.
+It ueses the official [actions/cache](https://github.com/actions/toolkit/tree/main/packages/cache) library.
+
+
+## Github Action Inputs
+
+| Variable                         | Description                                                                 |
+|----------------------------------|-----------------------------------------------------------------------------|
+| `args`                           | ***Required*** Arguments passed to `docker build` command                   |
+| `cache_key`                      | ***Required*** Key used for caching                                         |
+
+
+## Example Usage
+
+```
+uses: mattes/cached-docker-build-action@v1
+with:
+  args: --pull --file Dockerfile --tag my-image:tag .
+  cache_key: ${{ hashFiles('**/lockfiles') }}
+```
+
+## Future work
+
+  * Implement `expires` flag, blocked by [Clear cache #2](https://github.com/actions/cache/issues/2).
 
---pull		Always attempt to pull a newer version of the image

action.yml

@@ -12,10 +12,6 @@ inputs:
   cache_key:
     description: "Cache key"
     required: true
-  expires:
-    description: "Set expiration for cache (example '12 hours' or '3 days', ...)"
-
-# ${{runner.temp}} directory is guaranteed to be empty at the start of each job, even on self-hosted runners.
 
 runs:
   using: "node12"

index.js

@@ -12,7 +12,6 @@ const duration = require('parse-duration');
   // read and validate inputs
   const dockerBuildArgs = process.env["INPUT_ARGS"] || ""
   const cacheKey = process.env["INPUT_CACHE_KEY"] || ""
-  const expiresStr = process.env["INPUT_EXPIRES"] || ""
   const runnerTemp = process.env['RUNNER_TEMP'] || ""
 
   if (runnerTemp == "") {
@@ -32,7 +31,7 @@ const duration = require('parse-duration');
     return
   }
 
-  const primaryKey = sha256(`${cacheKey} ${dockerBuildArgs} ${expiresStr}`)
+  const primaryKey = sha256(`${cacheKey} ${dockerBuildArgs}`)
   const cachePath = path.join(runnerTemp, "cached-docker-build", primaryKey)
   let cacheHit = false
 
@@ -52,49 +51,25 @@ const duration = require('parse-duration');
     }
   }
 
-  // load docker image if it was cached and not expired
+  // load docker image if it was cached
   if (cacheHit) {
-    let expires = 0;
-    try {
-      expires = Number(fs.readFileSync(path.join(cachePath, ".meta.expires")));
-    } catch (err) {}
-
-    if (expires > 0 && Date.now() >= expires) {
-      core.info("Cache is expired")
-    } else {
-      exec(`docker load -i ${path.join(cachePath, "image.tar")}`, false);
-      core.info(`${dockerBuildTags.join(", ")} successfully loaded from cache`)
-      return
-    }
+    exec(`docker load -i ${path.join(cachePath, "image.tar")}`, false);
+    core.info(`${dockerBuildTags.join(", ")} successfully loaded from cache`)
+    return
   }
 
   // docker build/save and store meta data in cache path
   exec(`docker build ${dockerBuildArgs}`, true);
   exec(`mkdir -p ${cachePath}`, false);
   exec(`docker save -o ${path.join(cachePath, "image.tar")} ${dockerBuildTags.join(" ")}`, false);
 
-  // parse expiresStr into timestamp
-  let expires = 0
-  if (expiresStr != "") {
-    expires = Date.now() + duration(expiresStr, "ms")
-  }
-
-  if (expires > 0) {
-    fs.writeFileSync(path.join(cachePath, ".meta.expires"), expires)
-  }
-
   // save cache
   try {
     await cache.saveCache([cachePath], primaryKey);
   } catch (error) {
     core.error(error.message);
   }
 
-  if (expires > 0) {
-    let expiresDate = new Date(expires)
-    core.info(`Cache expires ${expiresDate.toUTCString()}`)
-  }
-
 })();