1 files changed, 79 insertions, 0 deletions
diff --git a/src/server/persistence_daemon.ts b/src/server/persistence_daemon.ts
new file mode 100644
index 000000000..388440b49
--- /dev/null
+++ b/src/server/persistence_daemon.ts
@@ -0,0 +1,79 @@
+import * as request from "request-promise";
+import { command_line, log_execution } from "./ActionUtilities";
+import { red, yellow, cyan, green } from "colors";
+import * as nodemailer from "nodemailer";
+import { MailOptions } from "nodemailer/lib/json-transport";
+
+const { LOCATION } = process.env;
+const recipient = "samuel_wilkins@brown.edu";
+let restarting = false;
+
+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 = `${LOCATION}:1050/serverHeartbeat`;
+    // if this is on our remote server, the server must be run in release mode
+    const suffix = LOCATION.includes("localhost") ? "" : "-release";
+    setInterval(async () => {
+        let response: any;
+        let error: any;
+        try {
+            response = await request.get(heartbeat);
+        } catch (e) {
+            error = e;
+        } finally {
+            if (!response && !restarting) {
+                restarting = true;
+                console.log(yellow("Detected a server crash!"));
+                await log_execution({
+                    startMessage: "Sending crash notification email",
+                    endMessage: ({ error, result }) => {
+                        const success = error === null && result === true;
+                        return (success ? `Notification successfully sent to ` : `Failed to notify `) + recipient;
+                    },
+                    action: async () => notify(error || "Hmm, no error to report..."),
+                    color: cyan
+                });
+                console.log(await log_execution({
+                    startMessage: "Initiating server restart",
+                    endMessage: "Server successfully restarted",
+                    action: async () => command_line(`npm run start${suffix}`, "../../"),
+                    color: green
+                }));
+                restarting = false;
+            }
+        }
+    }, 1000 * 90);
+}
+
+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) => resolve(dispatchError === null));
+    });
+}
+
+listen();
+\ No newline at end of file