Better Pi shutdown handling in Web Interface (#522)

* Add shutdown method

* Use shutdown method

* Use proto shutdown commands; remove old shell commands

* Add explicit monitor_rascsi shutdown

* Better method name

* Add code comment

* Fix bug

src/web/pi_cmds.py

@@ -22,22 +22,6 @@ def systemd_service(service, action):
             }
 
 
-def reboot_pi():
-    """
-    Reboots the Pi system
-    """
-    subprocess.Popen(["sudo", "reboot"])
-    return True
-
-
-def shutdown_pi():
-    """
-    Shuts down the Pi system
-    """
-    subprocess.Popen(["sudo", "shutdown", "-h", "now"])
-    return True
-
-
 def running_env():
     """
     Returns (str) git and (str) env

src/web/ractl_cmds.py

@@ -3,6 +3,7 @@ Module for commands sent to the RaSCSI backend service.
 """
 
 from settings import REMOVABLE_DEVICE_TYPES
+from pi_cmds import systemd_service
 from socket_cmds import send_pb_command
 import rascsi_interface_pb2 as proto
 
@@ -354,3 +355,26 @@ def set_log_level(log_level):
     result = proto.PbResult()
     result.ParseFromString(data)
     return {"status": result.status, "msg": result.msg}
+
+
+def shutdown_pi(mode):
+    """
+    Sends a SHUT_DOWN command to the server.
+    Takes (str) mode as an argument.
+    Returns (bool) status and (str) msg.
+    """
+    # This section proactively stops the monitor_rascsi systemd service, if running
+    # Otherwise, the monitor_rascsi script's interrupt handler won't take effect
+    monitor_service = "monitor_rascsi.service"
+    monitor_status = systemd_service(monitor_service, "show")
+    if "ActiveState=active" in monitor_status["msg"]:
+        systemd_service(monitor_service, "stop")
+
+    command = proto.PbCommand()
+    command.operation = proto.PbOperation.SHUT_DOWN
+    command.params["mode"] = str(mode)
+
+    data = send_pb_command(command.SerializeToString())
+    result = proto.PbResult()
+    result.ParseFromString(data)
+    return {"status": result.status, "msg": result.msg}

src/web/templates/base.html

@@ -29,6 +29,11 @@
         document.getElementById("flash").innerHTML = "<div class='message'>" + Notification + " This process may take a while, and will continue in the background if you navigate away from this page.</div>";
         window.scrollTo(0,0);
     }
+
+    var shutdownNotify = function(Notification) {
+        document.getElementById("flash").innerHTML = "<div class='message'>" + Notification + " The Web Interface will become unresponsive momentarily. Reload this page after the Pi has started up again.</div>";
+        window.scrollTo(0,0);
+    }
 </script>
 
 <script type="application/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/dropzone/5.9.3/min/dropzone.min.js">

src/web/templates/index.html

@@ -618,19 +618,19 @@
         Raspberry Pi Operations
     </summary>
     <ul>
-        <li>Issue reboot or shutdown commands to the Raspberr Pi.</li>
+        <li>Issue reboot or shutdown commands to the Raspberry Pi.</li>
         <li>You can also restart the RaSCSI backend service here.</li>
     </ul>
 </details>
 <table style="border: none">
     <tr style="border: none">
         <td style="border: none; vertical-align:top;">
-            <form action="/pi/reboot" method="post" onsubmit="return confirm('Reboot Pi?')">
+            <form action="/pi/reboot" method="post" onclick="if (confirm('Reboot the Raspberry Pi?')) shutdownNotify('Rebooting the Raspberry Pi...'); else event.preventDefault();">
                 <input type="submit" value="Reboot Raspberry Pi">
             </form>
         </td>
         <td style="border: none; vertical-align:top;">
-            <form action="/pi/shutdown" method="post" onsubmit="return confirm('Shutdown Pi?')">
+            <form action="/pi/shutdown" method="post" onclick="if (confirm('Shut down the Raspberry Pi?')) shutdownNotify('Shutting down the Raspberry Pi...'); else event.preventDefault();">
                 <input type="submit" value="Shut Down Raspberry Pi">
             </form>
         </td>

src/web/web.py

@@ -37,8 +37,6 @@ from file_cmds import (
     read_drive_properties,
 )
 from pi_cmds import (
-    shutdown_pi,
-    reboot_pi,
     running_env,
     systemd_service,
     running_proc,
@@ -60,6 +58,7 @@ from ractl_cmds import (
     get_device_types,
     reserve_scsi_ids,
     set_log_level,
+    shutdown_pi,
 )
 from device_utils import (
     sort_and_format_devices,
@@ -662,16 +661,6 @@ def unreserve_id():
     flash(process["msg"], "error")
     return redirect(url_for("index"))
 
-@APP.route("/pi/reboot", methods=["POST"])
-@login_required
-def restart():
-    """
-    Restarts the Pi
-    """
-    reboot_pi()
-    return redirect(url_for("index"))
-
-
 @APP.route("/rascsi/restart", methods=["POST"])
 @login_required
 def rascsi_restart():
@@ -705,13 +694,23 @@ def rascsi_restart():
     return redirect(url_for("index"))
 
 
+@APP.route("/pi/reboot", methods=["POST"])
+@login_required
+def restart():
+    """
+    Restarts the Pi
+    """
+    shutdown_pi("reboot")
+    return redirect(url_for("index"))
+
+
 @APP.route("/pi/shutdown", methods=["POST"])
 @login_required
 def shutdown():
     """
     Shuts down the Pi
     """
-    shutdown_pi()
+    shutdown_pi("system")
     return redirect(url_for("index"))