Added info about the differences with GitHub, and allow passing through GITHUB_TOKEN

README.md

@@ -30,7 +30,7 @@ Options:
   -h, --help         output usage information
 ```
 
-### Passing secrets
+### Supplying values for secrets
 
 You can set the value of [secrets](https://developer.github.com/actions/creating-workflows/storing-secrets/) defined in your workflow by passing them as environment variables, e.g.:
 
@@ -38,6 +38,14 @@ You can set the value of [secrets](https://developer.github.com/actions/creating
 MY_SECRET_TOKEN=yo-mamma gha
 ```
 
+### Differences with GitHub Actions
+
+Although this way of locally running GitHub Actions is very close to how they
+will work when actually running them on GitHub, there are a few small differences:
+
+* In the GitHub environment, the `GITHUB_TOKEN` is passed to all actions by default. This is not the case in the local environment, but can be achieved by creating a [personal token](https://github.com/settings/tokens/new?scopes=repo&description=GHA) and supplying it as a secret (see above).
+* The `/github/home` volume in the container is tied to your local directory `/tmp/gh-home`. In GitHub, this directory is container-specific, whereas this script shares it between all containers.
+
 
 ## Development
 
@@ -50,7 +58,3 @@ to add:
 - [ ] Add support for local Docker images: [`./path/to/dir`](https://developer.github.com/actions/creating-workflows/workflow-configuration-options/#using-a-dockerfile-image-in-an-action)
 - [ ] Add support for Docker Hub images: [`docker://{image}:{tag}`](https://developer.github.com/actions/creating-workflows/workflow-configuration-options/#using-a-dockerfile-image-in-an-action)
 - [ ] Add support for custom hosted Docker images: [`docker://{host}/{image}:{tag}`](https://developer.github.com/actions/creating-workflows/workflow-configuration-options/#using-a-dockerfile-image-in-an-action)
-
-Some improvements are also possible in other areas:
-
-- [ ] Add support for default [`GITHUB_TOKEN`](https://developer.github.com/actions/creating-workflows/storing-secrets/#github-token-secret) env var

lib/utils.js

@@ -130,6 +130,10 @@ const runAction = (actionTitle, actions, event, verbose) => {
     })
   }
 
+  if ('GITHUB_TOKEN' in process.env && !('GITHUB_TOKEN' in action.env)) {
+    action.env.GITHUB_TOKEN = process.env.GITHUB_TOKEN
+  }
+
   const uses = action.uses
   const imageName = resolveRunner(uses, verbose)
   let args = []