feat: validate workflow schema

.github/scripts/validate-workflow-schema.js

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+// Dependencies
+const core = require('@actions/core');
+const Ajv = require('ajv');
+const yaml = require('js-yaml');
+const fs = require('fs');
+const axios = require('axios').default;
+
+function validateYmlSchema(filename, validator){
+    // Read the schema and workflow file synchronously
+    const file = fs.readFileSync(filename, 'utf8');
+    try{
+        const target = yaml.load(file);
+        const valid = validator(target);
+        // Return the status and log for each workflow file validated
+        if (!valid) {
+            return {
+                'status' : false,
+                'log': validator.errors
+            }          
+        } else {
+            return {
+                'status' : true,
+                'log': 'Validation successful'
+            }
+        }
+    }
+    catch(err){
+        return {
+            'status' : false,
+            'log': err
+        }
+    } 
+}
+
+module.exports = async (allFiles) => {
+    const response = await axios.get('https://json.schemastore.org/github-workflow.json',{responseType: 'application/json'});
+    const schema = response.data;
+    const ajv = new Ajv({ strict: false, allErrors: true });
+    const validator = ajv.compile(schema);
+    const allLogs = {}
+    allFiles = allFiles.split(' ');
+    for(file of allFiles){
+        let log = validateYmlSchema(file, validator);
+        if(!log['status']){
+            allLogs[file] = log['log']
+        }
+    }
+    // Workflow fails if an error is detected in any file
+    if(Object.keys(allLogs).length > 0){
+        for(file in allLogs){
+            console.log("ERROR IN FILE " + file)
+            console.log(allLogs[file]);
+        }
+        core.setFailed('There are errors in the workflow files');
+    } else {
+        console.log('No errors detected in the yml/yaml files');
+    }
+}

.github/workflows/sample.yml

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+name: Erroneous yml file
+  This is a sample file that throws errors
+  Sample yml that throws errors

.github/workflows/validate-workflow-schema.yml

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+name: GitHub Workflows Schema Validation
+
+on:
+  pull_request: 
+    paths:
+        - '.github/workflows/*.yml'
+        - '.github/workflows/*.yaml'
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Validate workflow schema
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 
+
+      - name: Get changed files
+        id: changed-files
+        uses: tj-actions/changed-files@a59f800cbb60ed483623848e31be67659a2940f8 #version https://github.com/tj-actions/changed-files/releases/tag/v18.7
+        with:
+          path: .github/workflows 
+          files: |
+            .github/workflows/*.yml
+            .github/workflows/*.yaml
+
+      - name: Install dependencies
+        run: |
+            npm install [email protected]
+            npm install [email protected]
+            npm install [email protected]
+            npm install @actions/[email protected]
+
+      - name: Run script to validate schema
+        uses: actions/github-script@v6
+        with:
+          script: |
+            let files = `${{ steps.changed-files.outputs.all_changed_files }}`
+            const script = require('.github/scripts/validate-workflow-schema.js');
+            script(files);

sample.yml

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+name: Sample yml
+Sample yml file will not be tested