Preliminary work to pause/resume missions

app.py

@@ -66,6 +66,16 @@ def launch_mission():
     mission.parse_mission(mission_code)
     return ""
 
+@app.route('/pause_mission')
+def pause_mission():
+    mission.pause_mission()
+    return ""
+
+@app.route('/resume_mission')
+def resume_mission():
+    mission.resume_mission()
+    return ""
+
 # So that we can load DroneBlocks in an iframe
 static_file_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'droneblocks/dist')
 @app.route('/droneblocks/<path:path>', methods=['GET'])
@@ -89,7 +99,7 @@ def droneblocks(path):
     udp.start_listening()
 
     # Create the mission handler
-    mission = Mission(udp, camera)
+    mission = Mission(udp, camera, drone)
 
     # Handle Tello's state information
     telemetry = Telemetry(drone)

lib/drone.py

@@ -8,6 +8,7 @@ def __init__(self, is_aruco_tracking_enabled=False):
         self.is_aruco_tracking_enabled = is_aruco_tracking_enabled
         self.is_recording_video = False
         self.is_running_droneblocks_mission = False
+        self.is_paused = False
         self.pitch = None
         self.roll = None
         self.yaw = None

lib/mission.py

@@ -2,20 +2,33 @@
 
 class Mission():
 
-    def __init__(self, udp, camera):
+    def __init__(self, udp, camera, drone):
         self.udp = udp
         self.camera = camera
+        self.drone = drone
         self.test_command_string = "takeoff|fly_forward,20,in|yaw_right,90|land"
+        self.current_command_index = 0
+        self.is_mission_paused = False
+        self.resumed_mission = ""# This will contain the commands to resume the mission
 
 
     def parse_mission(self, mission_code):
 
         # Clear out any previous commands
         self.udp.clear_response()
 
+        # Reset the paused mission varables
+        self.current_command_index = 0
+        self.is_mission_paused = False
+        self.resumed_mission = ""
+
         # Split the mission into a command list
         commands = mission_code.split("|")
 
+        # Used so we can update pause/resume UI button
+        self.drone.is_running_droneblocks_mission = True
+        self.drone.is_paused = False
+
         # Remove any empty strings from the list. This can happen in cases where there is a mission without a takeoff block
         while ("" in commands):
             commands.remove("")
@@ -79,8 +92,9 @@ def parse_mission(self, mission_code):
 
                 delay = command.split(",")[1]
 
-                print("Delaying for ", delay, " seconds")
+                print("Hovering for ", delay, " seconds")
                 sleep(int(delay))
+                print("Done hovering")
                 command_to_execute = "command"
 
             elif "yaw_right" in command:
@@ -136,14 +150,42 @@ def parse_mission(self, mission_code):
             response = self.udp.get_response()
 
             if response == "ok":
-                print("finished executing command: " + command_to_execute + " with response: " + response)
+                print("Finished executing command: " + command_to_execute + " with response: " + response)
+
+                # Increment the command counter (used for pausing and resuming missions)
+                self.current_command_index = self.current_command_index + 1
+
                 # Delay 1 second before issuing the next command
                 sleep(1)
+
+                # If mission is paused let's break out of the command loop
+                if self.is_mission_paused:
+
+                    # Used to update the status so we can change the UI button to "Resume"
+                    self.drone.is_paused = True
+
+                    # Store the resumed mission in the string format so we can resume later
+                    self.resumed_mission = "|".join(commands[self.current_command_index:])
+                    print("Mission is paused. We'll resume mission with: " + self.resumed_mission)
+                    break
+
             else:
                 print("Here we could implement some retry logic or maybe even land. Response was " + response)
 
+        # Let's not trigger this code in cases where the mission is paused
+        if self.is_mission_paused is False:
+            print("Mission is complete!")
+            self.drone.is_running_droneblocks_mission = False
+
+    # Allow the user to pause the mission
+    # The mission will complete the current command being executed and then pause
+    def pause_mission(self):
+        self.is_mission_paused = True
+
+    # Pick up where we left off
+    def resume_mission(self):
+        self.parse_mission(self.resumed_mission)
 
-        print("Mission is complete")
 
 
     # Tello only flies in units of cm so we need to convert from in to cm

lib/udp.py

@@ -28,6 +28,7 @@ def recv():
                 try:
                     self.tello_response, _ = self.sock.recvfrom(128)
                     self.tello_response = self.tello_response.decode(encoding="utf-8")
+                    print("udp receive got a response: " + self.tello_response)
                 except Exception as e:
                     self.tello_response = None
                     print("Error receiving: " + str(e))

static/css/app.css

@@ -15,4 +15,11 @@
 
 .border {
     border: 1px solid #ff0000;
+}
+
+#pause {
+    position: absolute;
+    bottom: 50px;
+    left: 50%;
+    visibility: hidden;
 }

static/js/app.js

@@ -147,6 +147,20 @@ $(document).ready(function() {
                 $("#roll").text(response.roll + "°");
                 $("#pitch").text(response.pitch + "°");
                 $("#yaw").text(response.yaw + "°");
+
+                // Display pause button
+                if (response.is_running_droneblocks_mission) {
+
+                    if (response.is_paused) {
+                        $("#pause").html("Resume Mission");
+                    } else {
+                        $("#pause").html("Pause Mission");
+                        $("#pause").css("visibility", "visible");
+                    }
+
+                } else {
+                    $("#pause").css("visibility", "hidden");
+                }
             }
         });
     }, 500);
@@ -173,6 +187,18 @@ $(document).ready(function() {
         }
     });
 
+    // Handle pausing mission
+    $("#pause").click(function() {
+        let button_text = $(this).text();
+
+        if (button_text == "Pause Mission") {
+            $.get("/pause_mission", function(data){});
+        } else {
+            $.get("/resume_mission", function(data){});
+        }
+
+    });
+
 });
 
 // Called when a control command is being issued

templates/index.html

@@ -138,8 +138,9 @@
 
         </div>
 
-        <div class="uk-width-3-5">
+        <div class="uk-width-3-5" style="position: relative">
             <iframe src="/droneblocks/tello.html" width="100%" height="100%" id="droneblocks_iframe"></iframe>
+            <button class="uk-button uk-button-danger uk-button-small" type="button" id="pause">Pause Mission</button>
         </div>
     </div>
     <script src="../static/js/app.js"></script>