New HDD-LED applet to indicate drive r/w activity

hdd-led@tucsonst/README.md

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+# Drive Activity LED Indicator
+
+A Cinnamon desktop applet (Linux Mint) that adds a visual disk activity indicator (LED) directly to your system panel. This is a solution for laptop users or PC cases that lack a physical HDD activity LED. This applet is derived from storage-act-led@mrbartblog with some changes in how diskstats is parsed, look of the "LED" icons, and addition of a tooltip with r/w totals and a pop-up dialog with r/w counts for each disk in system.
+
+## Description
+The applet monitors system statistics and changes its icon color whenever a read or write operation is detected. This allows the user to see in real-time if the system is performing disk read/write operations.
+
+## Technical Details (`/proc/diskstats`)
+The applet works by parsing the `/proc/diskstats` file, which contains runtime block device statistics. It specifically tracks:
+* **Field 4**: Number of reads completed.
+* **Field 8**: Number of writes completed.
+The parsing eliminates loop devices, devmapper devices, and partitions which would cause double counting since these are summed up at the disk level.
+
+By comparing the current r/w values with the previous ones every **100ms**, the applet determines the current state:
+
+
+* ![LEDs off](files/hdd-led@tucsonst/icons/idle.svg) **Idle** - (both LEDs black/off) No changes in stats.
+* ![Green LED on](files/hdd-led@tucsonst/icons/read.svg) **Read** - (green LED on, red LED off) Increase in read count.
+* ![Red LED on](files/hdd-led@tucsonst/icons/write.svg) **Write** - (green LED off, red LED on) Increase in write count.
+* ![Both LEDs on](files/hdd-led@tucsonst/icons/both.svg) **Both** - (both LEDs on) Simultaneous increase in both read and write counts.
+
+## Requirements
+* **zenity**: This applet utilizes zenity to produce the drive activity pop-up dialog. Most standard Linux distributions, including Linux Mint, come with it pre-installed. 
+
+## Configuration
+Currently the applet sums the r/w counts of all disks in the system to determine r/w activity. A future enhancement would be to allow the user to select which disk devices to monitor.
+
+The refresh/measurement interval is set to **100ms**. This value can be changed directly in the `applet.js` code. However, in the author's opinion, 100ms provides a very accurate representation of how a physical LED built into a computer would behave – longer would be too slow, and shorter would be hard for the human eye to track.
+
+## Source & License
+This software is provided "as-is". 
+

hdd-led@tucsonst/files/hdd-led@tucsonst/applet.js

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+const UUID = "hdd-led@tucsonst";
+
+// Cinnamon-Spices applet to simulate a HDD activity LED on the system panel.
+// tucsonst - S. Tillman
+
+const Applet = imports.ui.applet;
+const Mainloop = imports.mainloop;
+const GLib = imports.gi.GLib;
+const Gio = imports.gi.Gio;
+const decoder = new TextDecoder("utf-8");
+const Util = imports.misc.util;
+
+const UPDATE_RATE_MS = 100;         // 100ms update time setting
+const TOOLTIP = _("Drive activity\n");
+const DISKSTATS = "/proc/diskstats";
+const DEVICE = _("Device");
+const READS  = _("Reads");
+const WRITES = _("Writes");
+const TOTALS = _("Totals");
+
+
+class HDDLEDapplet extends Applet.TextIconApplet {
+   constructor(metadata, orientation, panelHeight, instance_id) {
+       super(orientation, panelHeight, instance_id);
+
+        Gio._promisify(Gio.File.prototype, 'load_contents_async', 'load_contents_finish');        
+        this.set_applet_tooltip(TOOLTIP);
+        this.statinfo = TOOLTIP;
+        this.last_reads = 0;
+        this.last_writes = 0;
+        this.rows = 3; //rows of drive status for dialog box
+        this.set_applet_icon_name("idle");
+        this._update_loop();
+    }
+
+    async _getFileContent(file) {
+        try {
+            // Returns an array: [contents, etag]
+            const [contents] = await file.load_contents_async(null);
+
+            // 'contents' is a Uint8Array; convert it to a string if needed
+            const text = decoder.decode(contents);
+            return text; 
+        } catch (e) {
+            logError(e, 'Failed to load file');
+            return "";
+        }
+    }
+
+    async _get_disk_stats() {
+        let total_r = 0;
+        let total_w = 0;
+        let devstats = "";
+
+        let file = Gio.file_new_for_path(DISKSTATS);
+
+        let content = await this._getFileContent(file);
+        if (content == "") return {r: 0, W: 0, ds: ""};  //file read was unsuccessful 
+
+        let devname = "loop"; //skip the loop devices assuming these are first entries in diskstats
+        let devmap = "dm-"; //dev mapper prefix
+        devstats = `"--column=${DEVICE} --column=${READS} --column=${WRITES} "`;
+        let lines = content.split('\n');
+        this.rows = 0;
+
+        for (let line of lines) {
+            let parts = line.trim().split(/\s+/);
+            if (parts.length >= 7 && !(parts[2].startsWith(devname) 
+            || parts[2].startsWith(devmap))) { //Only count the disks, skipping partitions and dev mappers
+                total_r += parseInt(parts[3]);
+                total_w += parseInt(parts[7]);
+                devname = parts[2].trim();
+                devstats += `"${devname} " "${parts[3]} " "${parts[7]} "`
+                this.rows += 1;
+            }
+        }
+        return { r: total_r, w: total_w, ds: devstats };
+
+    }
+
+
+    async _update_loop() {
+        this.stats = await this._get_disk_stats();
+        let has_read = this.stats.r > this.last_reads;
+        let has_write = this.stats.w > this.last_writes;
+
+        if (has_read && has_write) {
+            this.set_applet_icon_name("both");
+        } else if (has_read) {
+            this.set_applet_icon_name("read");
+        } else if (has_write) {
+            this.set_applet_icon_name("write");
+        } else {
+            this.set_applet_icon_name("idle");
+        }
+        this.last_reads = this.stats.r;
+        this.last_writes = this.stats.w;
+        let statstip = "";
+        if (this.stats.ds != "") {
+        statstip = TOOLTIP + `${READS}: ${this.stats.r}\n${WRITES}: ${this.stats.w}`;
+        this.statinfo = `${this.stats.ds} "${TOTALS} " "${this.stats.r} " "${this.stats.w} "`
+        }
+        else {
+            statstip = TOOLTIP + _("Error processing ") + DISKSTATS;
+            this.statinfo = _("Error processing ") + DISKSTATS;
+        }
+        this.set_applet_tooltip(statstip);
+        this._timer_id = Mainloop.timeout_add(UPDATE_RATE_MS, () => {
+            this._update_loop();
+            return false;
+        });
+    }
+
+    on_applet_removed_from_panel() {
+        if (this._timer_id) {
+            Mainloop.source_remove(this._timer_id);
+        }
+    }
+
+    on_applet_clicked() {
+        let height = (this.rows+3) * 20 + 120; //rows of output x pixels/row + margin
+        const width = 3 * 15 * 10 // columns x avg chars/column x pixels/char
+        let cmd = "";
+        if (this.statinfo.startsWith(_("Error"))) {
+            cmd = `zenity --error --title=${UUID} --text="${this.statinfo}"`; 
+        }
+        else {
+            cmd = `zenity --list --title=${UUID} --height=${height} --width=${width} --text="Drive Activity" "${this.statinfo}"`;
+        }
+        Util.spawnCommandLine(cmd) ;
+    }
+
+}
+
+function main(metadata, orientation, panelHeight, instance_id) {
+    return new HDDLEDapplet(metadata, orientation, panelHeight, instance_id);
+}

hdd-led@tucsonst/files/hdd-led@tucsonst/credits.txt

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+This applet is based on storage-act-led@mrbartblog
+