Trigger backup from main database process.

Sqlite backups from the same database connection are much more efficient!
Externally triggered backups restart every time the database changes during
a backup, or need to lock the database exclusively for a long time.

We periodically look for a "backup.request" file, and if it exists
will write a backup. We write to "backup.tmp" first, and when finished
rename the file to "backup.db".

A crontab job can touch the "backup.request" file and then wait for the
"backup.db" file to appear.

1 files changed, 25 insertions, 0 deletions

diff --git a/server.js b/server.js
index af2fc65..859a409 100644
--- a/server.js
+++ b/server.js
@@ -2447,3 +2447,28 @@ app.get('/user-stats/:who_name', function (req, res) {
 		return res.status(404).send("Invalid user name.")
 	}
 })
+
+function backup_run() {
+	let start = Date.now()
+	console.log("BACKUP STARTED")
+	db.backup("backup.tmp")
+		.then(() => {
+			fs.renameSync("backup.tmp", "backup.db")
+			console.log("BACKUP FINISHED", Date.now() - start + "ms")
+		})
+		.catch((err) => {
+			console.log("BACKUP FAILED", err)
+		})
+}
+
+function backup_heartbeat() {
+	try {
+		fs.accessSync("backup.request", fs.constants.R_OK)
+		fs.unlinkSync("backup.request")
+		backup_run()
+	} catch (err) {
+		// no file exists!
+	}
+}
+
+setInterval(backup_heartbeat, 60 * 1000)