1 files changed, 92 insertions, 0 deletions
diff --git a/src/server/daemon/persistence_daemon.ts b/src/server/daemon/persistence_daemon.ts
new file mode 100644
index 000000000..3eb17a9b4
--- /dev/null
+++ b/src/server/daemon/persistence_daemon.ts
@@ -0,0 +1,92 @@
+import * as request from "request-promise";
+import { log_execution, spawn_detached_process } from "../ActionUtilities";
+import { red, yellow, cyan, green } from "colors";
+import * as nodemailer from "nodemailer";
+import { MailOptions } from "nodemailer/lib/json-transport";
+import { writeFileSync } from "fs";
+import { resolve } from 'path';
+
+const LOCATION = "http://localhost";
+const recipient = "samuel_wilkins@brown.edu";
+let restarting = false;
+
+writeFileSync(resolve(__dirname, "./current_pid.txt"), process.pid);
+
+function timestamp() {
+    return `@ ${new Date().toISOString()}`;
+}
+
+async function listen() {
+    if (!LOCATION) {
+        console.log(red("No location specified for persistence daemon. Please include as a command line environment variable or in a .env file."));
+        process.exit(0);
+    }
+    const heartbeat = `${LOCATION}:1050/serverHeartbeat`;
+    // if this is on our remote server, the server must be run in release mode
+    // const suffix = LOCATION.includes("localhost") ? "" : "-release";
+    setInterval(async () => {
+        let error: any;
+        try {
+            await request.get(heartbeat);
+        } catch (e) {
+            error = e;
+        } finally {
+            if (error) {
+                if (!restarting) {
+                    restarting = true;
+                    console.log(yellow("Detected a server crash!"));
+                    await log_execution({
+                        startMessage: "Sending crash notification email",
+                        endMessage: ({ error, result }) => {
+                            const success = error === null && result === true;
+                            return (success ? `Notification successfully sent to ` : `Failed to notify `) + recipient;
+                        },
+                        action: async () => notify(error || "Hmm, no error to report..."),
+                        color: cyan
+                    });
+                    console.log(await log_execution({
+                        startMessage: "Initiating server restart",
+                        endMessage: "Server successfully restarted",
+                        action: () => spawn_detached_process(`npm run start-spawn`),
+                        color: green
+                    }));
+                    restarting = false;
+                } else {
+                    console.log(yellow(`Callback ignored because restarting already initiated ${timestamp()}`));
+                }
+            } else {
+                console.log(green(`No issues detected ${timestamp()}`));
+            }
+        }
+    }, 1000 * 10);
+}
+
+function emailText(error: any) {
+    return [
+        `Hey ${recipient.split("@")[0]},`,
+        "You, as a Dash Administrator, are being notified of a server crash event. Here's what we know:",
+        `Location: ${LOCATION}\nError: ${error}`,
+        "The server should already be restarting itself, but if you're concerned, use the Remote Desktop Connection to monitor progress."
+    ].join("\n\n");
+}
+
+async function notify(error: any) {
+    const smtpTransport = nodemailer.createTransport({
+        service: 'Gmail',
+        auth: {
+            user: 'brownptcdash@gmail.com',
+            pass: 'browngfx1'
+        }
+    });
+    const mailOptions = {
+        to: recipient,
+        from: 'brownptcdash@gmail.com',
+        subject: 'Dash Server Crash',
+        text: emailText(error)
+    } as MailOptions;
+    return new Promise<boolean>(resolve => {
+        smtpTransport.sendMail(mailOptions, (dispatchError: Error | null) => { console.log(dispatchError); resolve(dispatchError === null); });
+    });
+}
+
+listen();
+\ No newline at end of file