Add initial action files

action.yml

@@ -0,0 +1,30 @@
+name: 'Slack errors'
+description: 'Send build errors summary message to Slack'
+inputs:
+  slack-webhook-url:
+    description: 'Slack webhook URL'
+    required: true
+    default: ''
+  branch-name:
+    description: 'Branch name'
+    required: true
+    default: ''
+  commit-sha:
+    description: 'Run commit SHA'
+    required: true
+    default: ''
+  commit-owner:
+    description: 'Owner of commit'
+    required: true
+    default: ''
+  repo-name:
+    description: 'Repository name'
+    required: true
+    default: ''
+  run-id:
+    description: 'Build run ID'
+    required: true
+    default: ''
+runs:
+  using: 'node12'
+  main: 'index.js'

index.js

@@ -0,0 +1,113 @@
+const core = require('@actions/core');
+const fs = require('fs');
+const glob = require("glob");
+const https = require('https');
+
+const branchName = core.getInput('branch-name');
+const commitOwner = core.getInput('commit-owner');
+const commitSha = core.getInput('commit-sha');
+const repoName = core.getInput('repo-name');
+const runId = core.getInput('run-id');
+const slackWebhookUrl = core.getInput('slack-webhook-url');
+
+function prepareErrorOutput() {
+  return new Promise((resolve, reject) => {
+    glob("job-*.txt", {nonull: true}, function (err, files) {
+      if (err) { reject("Unable to parse files") };
+
+      // If there is only one matching file, it is the 'initiate-error-tracking' file
+      // No other matching files indicates the build ran without issue
+      if (files.length === 1) { resolve("") };
+
+      fullErrors = ""
+      for (let i=0; i<files.length; i++) {
+        try {
+          fullErrors += fs.readFileSync(files[i], 'utf8')
+        } catch (err) {
+          reject("Failed to read", err);
+        }
+      }
+      resolve(fullErrors);
+    })
+  })
+}
+
+function errorNotification (errors) {
+  return {"blocks":[
+    {
+        "type":"header",
+        "text":{
+          "type":"plain_text",
+          "text":`CI build failed for commit ${commitSha.substring(0,9)} on ${branchName.replace("refs/heads/", "")}`
+        }
+    },
+    {
+        "type":"section",
+        "text":{
+          "type":"mrkdwn",
+          "text":`— _Author: ${commitOwner}_  <https://github.com/${repoName}/actions/runs/${runId}|View build>`
+        }
+    },
+    {
+        "type":"section",
+        "text":{
+          "type":"mrkdwn",
+          "text":`\n ${errors}`
+        }
+    }
+  ]}
+};
+
+async function makePostRequest(webhookUrl, messageBody) {
+  return new Promise((resolve, reject) => {
+    const options = {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json'
+      }
+    }
+
+    const req = https.request(webhookUrl, options, res => {
+      let response = '';
+      res.on('data', d => {
+        response += d;
+      });
+      res.on('end', () => {
+        resolve(response);
+      });
+    });
+
+    req.on('error', err => {
+      reject(err)
+    })
+
+    req.write(JSON.stringify(messageBody));
+    req.end();
+  });
+};
+
+async function sendSlackNotification(message) {
+  try {
+    await makePostRequest(slackWebhookUrl, message);
+    console.log("Errors successfully reported to Slack")
+  } catch (err) {
+    console.error('There was a error reportig to Slack', err);
+  }
+};
+
+async function prepareAndSendNotification() {
+  const buildErrors = await prepareErrorOutput()
+
+  if (buildErrors === "") {
+    console.log("Slack message not sent, no build errors to report")
+  } else {
+    const slackMessage = errorNotification(buildErrors)
+    await sendSlackNotification(slackMessage);
+  }
+}
+
+try {
+  prepareAndSendNotification();
+} catch (err) {
+  core.setFailed(err.message);
+}