Merge pull request #2 from jannekem/check_return_code

Add error handling

Author: jannekem

.github/workflows/check-build.yaml

@@ -0,0 +1,15 @@
+name: Check build
+
+on: push
+
+jobs:
+  check-build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: "14"
+      - run: npm install
+      - run: npm run build
+      - run: git diff --exit-code

README.md

@@ -29,3 +29,45 @@ jobs:
             for f in os.listdir():
                 print(f)
 ```
+
+## Handling errors
+
+By default, the action will fail if it encounters any errors when trying to run your script. You can override this with the `fail-on-error` input.
+
+The action sets three outputs:
+
+- `stdout` contains any text that your program prints to the console
+- `stderr` contains any text that is routed to STDERR, such as exception messages
+- `error` is a string with either `"true"` or `"false"` depending on if errors were present or not, use this to check for errors when you opt not to fail the step
+
+Look at the following snippet to see how the error handling works in practice:
+
+```yaml
+name: Run Script
+
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - uses: jannekem/run-python-script-action@v1
+        id: script
+        with:
+          fail-on-error: false
+          script: |
+            print("Doing something that will fail")
+            a = []
+            a[10]
+      - name: Print errors
+        if: steps.script.outputs.error == 'true'
+        run: |
+          printenv "SCRIPT_STDOUT"
+          printenv "SCRIPT_STDERR"
+        env:
+          SCRIPT_STDOUT: ${{ steps.script.outputs.stdout }}
+          SCRIPT_STDERR: ${{ steps.script.outputs.stderr }} 
+```

action.yml

@@ -4,6 +4,17 @@ inputs:
   script:
     description: "Python script"
     required: true
+  fail-on-error:
+    description: "Fail step if the return code from running the script is non-zero"
+    required: false
+    default: true
+outputs:
+  stdout:
+    description: "Program stdout"
+  stderr:
+    description: "Program stderr"
+  error:
+    description: "A string of 'true' or 'false' that tells if there were errors, use in conjunction with the fail-on-error input"
 runs:
   using: "node12"
   main: "dist/index.js"

dist/index.js

@@ -4,11 +4,37 @@ const fs = require('fs');
 const tmp = require('tmp');
 
 async function run() {
+    const script = core.getInput("script");
+    const failOnError = core.getInput("fail-on-error") === "true";
+
+    let stdout = "";
+    let stderr = "";
+    let errorStatus = "false";
+    const options = {};
+    options.listeners = {
+        stdout: (data) => {
+            stdout += data.toString();
+        },
+        stderr: (data) => {
+            stderr += data.toString();
+        }
+    };
+
     tmp.setGracefulCleanup();
-    const script = core.getInput('script');
     const filename = tmp.tmpNameSync({postfix: '.py'});
     fs.writeFileSync(filename, script);
-    exec.exec('python', [filename])
+    try {
+        await exec.exec('python', [filename], options);
+    } catch (error) {
+        errorStatus = "true";
+        if (failOnError) {
+            core.setFailed(error);
+        }
+    } finally {
+        core.setOutput("stdout", stdout);
+        core.setOutput("stderr", stderr);
+        core.setOutput("error", errorStatus);
+    }
 }
 
 run();